Is this possible? They drill a hole and chamfer it on the rod journal face of cranks for V8's. Does anyone do that for our cranks or has tried it? It improves oiling in that area, supposedly. It's a pretty standard thing on V8's...

Is it hollow in there? If someone local wanted to find out, I've got a few crap cranks laying around.

About the only person I know of I would trust to do this correctly is a guy named Castillo (Castillo's Crankshafts) in SoCal; he's one of the best, and he would know how to do it correctly. It's not just the galleys, it's the timing of the holes in relation to the piston position / TDC / 90* ATDC, and whether or not the oil will aerate.

Alot to think about, and I'm not educated enough to do it. :lol:

S.

Out on the cutting edge again I see, or at least the rotating one. :)

I've only talked to Ron at Axis about it. The holes he drills are "timed" to give the rod bearing oil 20* BTDC just as the journal is to be fully extended. Ron has a guy there in St. Louis how has developed a jig to do the drilling. As far as I know, the drilling that is done is based on the Spec C crank. I never asked Ron directly.

All my crankshaft reading lead me to believe that drilling could help, but not that it would help. I'm sure someone out there has some theory that is backed by empirical research, but I've not met them yet. It's a multi-demensional problem that I would think very hard to model, but I'll bet someone like Castillo could shed some light.

If the oil is going to exit the journal face, it has to get there first. I would seriously doubt that the casting supporting the rod journals is hollow:

a. if the channels were made in the casting process, why don't they use them now? how would you balance something like that for a production car cost effectively?

b. to bore the holes down the journal supporting structures would require a machine that would bore slowly to keep heat down and also keep the bit tracking inside the support. this would result in atleast 5 borings and 4 plugged holes per journal. If the bit exited any place other than the main shaft of the crank, you would hear the fat lady sing.

in summary with 100% confidence, expect it to cost more than a crank made that way in the first place.

Ron from Axis does drill hles into his crankshafts. this is how he gets his motors to spin higher RPMs. i have seen the holes drilled on my own crankshaft. it is very nicely done and chamfered.

More holes means more oil is needed to be flowed meaning you will need to raise your oil pressure or volume to support the modification to the crank.

They're not that big dude. Just one hole per journal at less than 1/4in. diameter. Your talking MAYBE a 1/4 cup of oil for volume.

I was just pointing out the dynamics of oil, no disrespect meant. Try this, blow through one straw and then blow through 2. You will find that it's easier to blow through 2 at a time.

Now try this: Fill your mouth with water and squirt the water through a single straw. Measure how far you can squirt it. Now do the same with 2 straws but this time think about the extra effort you have to use to get the water to squirt the same distance.

Now think about a second hole in the crank again. I am not saying it's a bad thing, I'm saying you need to raise the oil pressure to account for it. One method of doing this is the extra shims in the oil pump. I've posted pictures and information on how to do this in the past, here are the pictures again.

http://www.mickandsarah.com/wrx/misc/oil-pump-mod-0001.jpg

http://www.mickandsarah.com/wrx/misc/oil-pump-mod-0002.jpg

You really don't need to raise the oil pressure, you need to raise the oil flow.

Either way, I think that holes that let off to bearings would create a neglidgable loss in pressure because they have to push through a gap that is so small (between crank and bearing).

You really don't need to raise the oil pressure, you need to raise the oil flow.

Either way, I think that holes that let off to bearings would create a neglidgable loss in pressure because they have to push through a gap that is so small (between crank and bearing).

Pick on the Red Haired kid why don't you :)

I've been working with a long time race block builder and am constantly surprised at what they do in a *real* race block to improve oiling. I don't class my block as a race block. You are correct the issue would be volume. I raised my oil pressure to force a higher pressure float layer. The oil is being pushed through the small crank to bearing surface. The key is to keep the crank floating on the oil....

I have a Axis drilled and balanced crankshaft in my EJ257. I also have a modded 2.2 oil pump to keep up with the extra oil flow. Yes, i have taken my engine to 8000rpm many times with no problems. Have about 9000 miles on the engine so far and still runs great!! This is by far the smoothest running engine i have driven....about JDM smooth!!

V8 guys aren't the only ones doing this. We do this on all the Porsche cranks that we use in race builds or high performance street rods we build in our shop. On the Subaru side, it isn't just the spec C cranks that get it. I have seen a v4 STi crank that had it as well, while my v1 STi crank does not have it. It seems it's something Subaru learned over time. I am currently shopping for an Ej22T block as a builder, and it's one of the things I have on the list to make it reliable and ready to rev...

Good to see such a response on this subject. What other kinds of machining "tricks" might there be that you guys are willing to let out of the bag? Can I do this to my EJ257 crank without much issues? I always kinda wondered how you upped the oil pressure in our blocks. Would I need an STI specific pump if I built up my USDM N/A 2.5L? Rick isn't wanting to push the blowers that hard, so I'm still considering an n/a build running on this alcohol fuel and some spray. I'm pretty positive I can crack 12's up here and not beat on the car in the process. I just wanna whip on STI's with an n/a car :P.

Fast and smooth is one of the things I'm looking for. Improving reliability at those high revs is very high on my list. The revs will be kept reasonable at 7500-ish, tops. A broad and flat torque curve is my goal. Something that is very useable for auto crossing where I'll be spending most of my time truthfully in 2nd gear. Being on and off the throttle in rapid successions, how does that affect intertial loads on my rotating assembly? Comparing it to a blower setup, I'm thinking of how the shearing forces and vibrations affect things. I hear most rod and bearing failures on trailing throttle at higher rpms, or immediately after such events. Improving oiling and oil control is high on my list, but I'm not quite sure how to get there since I don't work in a machine shop all day.

You really don't need to raise the oil pressure, you need to raise the oil flow.

Either way, I think that holes that let off to bearings would create a neglidgable loss in pressure because they have to push through a gap that is so small (between crank and bearing).



This is exactly right.. it is about volume at that point.
If you added higher compression pistons to an engine, you would have to tune the car different.
If you change something in your oil system, you must also account for this.

all this talk about oil... i wonder if anyone has done a basic 3 stage dry sump system?

*no intention of jacking this thread*

Threadjack welcome...

I plan in installing high compression pistons in my N/A build if I go that route. Because of my altitude and the fuel I can go up to 14:1. 13:1 seem like a safe back-off point though. How does high compression affect oil pressure requirements? 02Toyo...were you just making a comparison and I misunderstood?

What other kinds of machining "tricks" might there be that you guys are willing to let out of the bag?

Sure. Email me. n2xlr8n@comcast.net

I'm not willing to post it in my Webshots album, but I'll give it to anyone interested in experimenting. It's never been done on a Subaru, to my knowledge.

S.

Are oil pumps positive displacement pumps, or near-so? What exactly does shimming the pump do? (and I don't mean "raises pressure", what does it fundamentally do that raises pressure? why does it work, etc?)

Are oil pumps positive displacement pumps, or near-so? What exactly does shimming the pump do? (and I don't mean "raises pressure", what does it fundamentally do that raises pressure? why does it work, etc?)


Changes the amount of oil bypassed, I imagine.

S.

all this talk about oil... i wonder if anyone has done a basic 3 stage dry sump system?

*no intention of jacking this thread*


Yes and this solves the problems with the Subarus oiling system.

Yes and this solves the problems with the Subarus oiling system.

so have you done this, or know someone who has? i would definetly like to see some install pics if you have any.

Are oil pumps positive displacement pumps, or near-so?

Yes, they're positive displacement.

More holes means more oil is needed to be flowed meaning you will need to raise your oil pressure or volume to support the modification to the crank.

This is correct. Any of Ron @ Axis' blocks that have his cross-drilled cranks include an upgrade oil pump (shimed EJ22T oil pump). There is obviously a reason for this.

-Matt

So would it make sense to use a lighter viscosity oil once you increase the pressure in order to increase flow and bring the pressure back down a little bit?

I don't buy the oil pressure argument at least for oiling the crank. A few centrifugal force calculations and you'll see the oil is being flung out of the rod journals and no pressure is going to maintain it. I think it's got to be drilled to synch the oil pick-up with the flinging to keep a continous film of oil on the bearings.

Shimming works just like a fuel pressure regulator, the smaller apeture that shimming creates makes pressure behind it proportional to the size of the opening.

I'd ask Ron why he shims the pump. I'm not sure it's for the crank's benefit. The path of the oil through the engine may come into play and a reduced flow/volume with shimming could be beneficial. For instance if you push all the oil into the heads, there's nothing there for the crank, pistons, etc. I don't know, but Ron would.

I was just pointing out the dynamics of oil, no disrespect meant. Try this, blow through one straw and then blow through 2. You will find that it's easier to blow through 2 at a time.

Now try this: Fill your mouth with water and squirt the water through a single straw. Measure how far you can squirt it. Now do the same with 2 straws but this time think about the extra effort you have to use to get the water to squirt the same distance.

Now think about a second hole in the crank again. I am not saying it's a bad thing, I'm saying you need to raise the oil pressure to account for it. One method of doing this is the extra shims in the oil pump. I've posted pictures and information on how to do this in the past, here are the pictures again.

http://www.mickandsarah.com/wrx/misc/oil-pump-mod-0001.jpg

http://www.mickandsarah.com/wrx/misc/oil-pump-mod-0002.jpg

Ron recommends this as well. unless you go with a dry sump system or better oil pump.

im not seeing where the "shimming" is. do you shim the little allen nut and spring thingy?

~Josh~

Yes and this solves the problems with the Subarus oiling system.

In regards to the dry sump set-up do you have first hand experience with this? If so would you like to share what info do you have?

The little washer looking thingies are the shims. They "shim" a spring loaded pintle (you can see the spring in pic 1). By shimming the spring pushes the valve closed harder.

The shim is to raise the by-pass relief valve pressure. The oil pump is a positive displacement pump, so at a given rpm it always moves the same amount of oil. Oil above and beyond what the bearings will actually accept, is bypassed by the relief valve.

For what its worth, most aftermarket crankshaft manufactures are no longer cross drilling racing cranks as is has not proven itself a useful modification to keep the engines alive. It was first used in low rpm high load diesel engines, and for a time was considered "the hot setup". Current wisdom is that it takes oil away from the rods, and adds an additional weak point for crank failure.

Its more important to "detail" the engines oil supply system in my opinion.

At high rpm, it takes pressure to drive the oil into the mains because your fighting centrifugal force which is trying to throw the oil back out of the main journal.

This is one of the reasons folks have started to run "honda" size main journals (in addition to lower bearing friction due to lower surface speeds)

At high rpm, oil pressures can become low enough in the center of the crank shaft main journal to cause gas dissolved in the oil to form bubbles, these can then block flow of liquid oil out to the rod journals. To prevent this form of bubble generation you must maintain high enough system oil pressures to prevent bubble generation at high rpms. Anything that tends to drop oil pressure inside the journal at high rpm is counterproductive.

http://www.engin.umd.umich.edu./research/undergraduate/reports/REUReport3-ConRodLubeFlow-2004.doc.pdf

http://www.tytlabs.co.jp/english/review/rev383epdf/e383_044suzuki.pdf

http://www.rehermorrison.com/techTalk/51.htm

The subaru 2.0 L wrx crank is already a cross drilled design. The main journal has an oil passage that passes all the way across the journal, as does the rod journal. These are connected by a passage drilled to pass through the center of the rod journal passage to the center of the main journal passage.

So at high rpm the oil pressure must be suffecient to push oil against centrifugal force into the center of the main journal. That is an oil column 30 mm long. If any of you physics/engineer types want to tackle figuring out the oil pressure due to centrifugal force at the journal at 8000 rpm it would be useful to the discussion.

FWIW

Larry

I'm guessing that we're talking about a pseudo oil-squirter that lets oil out of the crankshaft to shoot towards the piston/wrist-pin? Obviously we're not talking about lubricating the area where the rod connects to the crank, since that already has such a hole.

:confused:

Obviously we're not talking about lubricating the area where the rod connects to the crank, since that already has such a hole.

No we are not talking about the wrist pin.
Yes we are talking about oil to the rod and main bearing journals, not the wristpin which is oiled by oil sling off the crank.

Larry

No we are not talking about the wrist pin.
Yes we are talking about oil to the rod and main bearing journals, not the wristpin which is oiled by oil sling off the crank.

Larry

And the oil scraped off the cylinder wall by the the oil rings too. :)

S.

No we are not talking about the wrist pin.
Yes we are talking about oil to the rod and main bearing journals, not the wristpin which is oiled by oil sling off the crank.

Larry

Sooooo ... don't the rod journals already have an oil-line running from the crankshaft to them as seen here: http://img.photobucket.com/albums/v14/SaabTuner/EJ_crankshaft_drawing.jpg

Are we talking about adding another hole? Sorry for being lost here. :o

And the oil scraped off the cylinder wall by the the oil rings too. :)

S.

Which comes from oil being slung off the crank into the cyllinder walls. :P :D

don't the rod journals already have an oil-line running from the crankshaft to them

Yes they do --- the problem is how that oil feed is supplied with oil. Each of the journals are already cross drilled so as far as the original question for this thread it is a moot point. You can't add cross drilling if it already exists.

The question is now is cross drilling a good thing to do, and the pro's say no not for a high rpm engine. It works great right up to the point that high rpm centrifugal force cuts off effective oil flow to the rod bearings.

The problem with cross drilled journals of the design used in the subaru is where the oil feed intesects the oil passage in the main journal. As drilled on the 2.0 L wrx crank the oil feed hole goes from the center of the rod journal to the center of the main journal passage. That means that before the oil can even enter the oil feed passage to the connecting rod journal, it must move against centrifugal force into the center of the main journal. At high RPM that centrifugal force creates enough reverse pressure to nearly stop all oil feed to the rod journal.

Lets grab some numbers out of the air. The Stock subaru oil pump has its pressure relief valve set at 71 psi for the high pressure relief. Based on the long standing rule of thumb that you need 10 psi for each 1000 rpm of crank speed, that means the oil system is not suitable for extended time above 7000 rpm.

[ edit correction ] 71 psi is the relief pressure on the non-turbo engines, turbo engines relief valve is set at 85 psi, so the oil pressure is just adequate for 8000 rpm, with a non-cross drilled crank, but stock bearing clearances may not be loose enough. Many domestic race engine builders will not run bearing clearences tighter than 3.5 thousands of an inch to keep their 8000-9000+ rpm engines alive. [end edit]

Lets say at 8000 rpm you have that pressure valve limited system pressure at 71 psi and the centrifugal force trying to throw the oil out of the main bearing cross drilled passage is creating 40 psi of pressure (just an educated guess), your real flow is what you would get at a system pressure of 31 psi at low rpm. Now add to that the fact that in a cross drilled passage you have centrifugal force trying to pull the oil out both sides of the passage, so you end up putting a strong suction on the oil near the center of the bearing journal. At high oil temps and with just a bit of air absorbed in the oil, all of a sudden you have gasses coming out of solution in the oil at the center of the crank journal so what little flow you have to the rod journal now has bubbles in it.

Any slight hickup in oil supply pressure due to sucking a bit of air at the oil pan pickup during a hard turn or launch and bang you just lost all oil pressure to the rods at the worst possible time (ie high rpm).

On the conventional drilling, ( the so-called V passage in the ref article) the oil passage from the rod journal to the main journal intersects the main oil feed very near the surface of the journal so it has to fight much less centrifugal force to get into the passage leading to the rod. Its not a huge improvement but enough to significantly reduce the likelyhood of generating bubbles in the oil.

Since the subaru has 360 degree grooved mains (behind the bearing shell) in the block, cross drilling is sort of meaningless anyway as oil is fed to the bearing at each oil feed hole in the bearing.

Larry

Sooooo ... don't the rod journals already have an oil-line running from the crankshaft to them as seen here: http://img.photobucket.com/albums/v14/SaabTuner/EJ_crankshaft_drawing.jpg

Are we talking about adding another hole? Sorry for being lost here. :o
That's the way they are drilled. And yes a second hole/tube.

Along the centerline (axis) of the crank the centrifugal force is zero (or nearly). As the radius increases so does the outward force. As the speed of the crank increases (RPM) the force with which oil is being flung increases exponentially. (Sit at the center of a merry-go-round and you are not flung outward, you just spin-->see also spining of tops and gyroscopes)

Now, oil enters (under oil pressure) the one hole of the main journal at the centerline (or near it) and gets flung (scientific term) out toward the rod journal. This is happening constantly (i.e. nothing to do with the engine's cycle).

We do have spun rod bearings so something wrong is happening.

The fear is that with just one hole, the rate of oil entering the main journal (under oil pressure) will not equal the rate of oiling leaving the tube that connects the main and rod journals (can you say vacuum in the oiling tube-->cavatation). When oil leaves faster than it is fed into the tube, due to high centirfugal force, starvation at the rod bearing is a possibility.

The addition of a second hole (that flings more oil to the rods) will at least help. It provides a second path for oil to move from the main journal to the rod journal. To some degree the fling can be controlled to provide oil at a certain position in the pistons cycle by the position of the hole on the rod journal (even though the centrifugal flow/force is constant, at least there can be oil flung when it's needed the most).

As far as I understand the term "cross-drilling". Our rod journals are not cross-drilled.

Centrifugal Force=mass*rotation^2*radius
I can't remember the units or I calculate a psi for a oil droplet at the rod bearing. The main thing to observe is that as rotation speed increases, the force increases by it's square. The difference between 7000 RPM and 8000 RPM is huge!!

My cliff notes (please correct if wrong!):

Additional cross drilling is not good for high RPM due to centrifugal force on the crank/rod/oil causing reduced oil pressure at the bearing.
More oil pressure is required to maintain oil pressure at bearings at high RPM due to previously mentioned centrifugal force.
Stock drilled crank + shimmed oil pump + high RPM FTW! ;)

As far as I understand the term "cross-drilled" our crankshaft journals are not, and the drilling modification of our cranks offered by several vendors are not cross-drilled either.

As far as I understand the term "cross-drilled" our crankshaft journals are not, and the drilling modification of our cranks offered by several vendors are not cross-drilled either.

Both the main journals and the rod journals are drilled all the way through ( across the diameter of the journal) That is the definition of crossdrilled. If you stick a rod in the oil feed hole on the main journal it comes out the opposite side of the journal, not out the rod journal as it would on some cranks.

This web page has a picture of a subaru crank. http://www.drive.subaru.com/SubaruDrive-Sum02/Piston-Cranky.asp

Closer look at the cross drilled journals in a broken crankshaft.
http://www.demeis.com/images/mcrankcrack.jpg

The oil feed holes you see are drilled through and through the journals, across the diameter of the journal. If you look closely at the ends of the rod journals you will see a small depression this is the plugged end of the connecting passage that passes through the "center" of both cross drills in the rod journals and the main journals.


As you can see here, the main journals are fed 360 degrees behind the bearing shell.

http://www.demeis.com/images/mspunjourn.jpg

This web page shows conventionally drilled crankshaft where the oil feed galley to the rod journal comes directly off the surface of the main journal.

http://www.mustangandfords.com/howto/29178/

Some engines plug one end of the cross drilled journal with a soft plug, some Porsche 912's and some Alfas do that. If the soft plug comes out the oil pressure drops about 5 psi. In MGA's the soft plug is a restrictor (has a small hole in it) to force more oil into the rod galley than out the other side of the main bearing.
Larry

Yes mains are cross-drilled but not the rod journals. It's the passage from the mains to the rod journals that is the trouble spot. I've never heard of a spun main bearing, at least not from high RPM.

Yes mains are cross-drilled but not the rod journals.

Hmmm then why can I look all the way through the hole that goes through the rod journal of the crankshaft I have sitting beside me ? ;)

Both the mains and the rod journals are cross drilled.

As you say the mains are not the problem, the problem is inadequate flow to the rod journal. By having a cross drilled main, you have two paths for the oil, one to the rod journal passage and the other out the opposite side of the main. This "leak" reduces oil flow to the rod, so the main has plenty of oil but at high rpm the rod journal is throwing off oil faster than it can be re-supplied by the main oil feed. If the oil gets just a hint of air in it, the rod runs out of oil as it slings the oil out and pulls that air out of the center of the main bearing journal cross drill passage.

The solution might be as simple as what MGA did and put a soft plug in one side of the main journal cross drill passage.

http://www.ai5.net/~speed_tech@ai5.net/crossdrilled_wrx_crank.jpg

Larry

Well that settles it. They are cross drilled. I don't remember that, but the rods were on the crank when Axis returned it.

Well that settles it. They are cross drilled. I don't remember that, but the rods were on the crank when Axis returned it.
bboy, you have a 2.5l and Hotrod is talking about a 2.0l.
is the 2.5l cross drilled? obviously the 2.0l is.
just wanted to make sure everyone was on the same page.

bboy, you have a 2.5l and Hotrod is talking about a 2.0l.
is the 2.5l cross drilled? obviously the 2.0l is.
just wanted to make sure everyone was on the same page.

EJ257 is the same. :)

S.

If anyone have one of the JDM crankshafts laying around? I would love to see the changes they made in the oil supply drillings. I understand it was different but have never seen one up close and personal.

Larry

so have you done this, or know someone who has? i would definetly like to see some install pics if you have any.

Ive done a 3 stage in the past, dont have any pictures.. sorry.
Currently im in the process of putting together a more extensive 5 stage, which I can take pictures of. Ill keep you updated, this is an ongoing project.

If any pin is crossdrilled like the picture above wouldnt that not be good? crankshaft spinning at X-rpm's which way is the oil sposed to flow, or does it kind of fight itself back and forth?

Not sure what your asking, the cross drill is intended to give the oil 2 different paths to get to the oil galley that runs up the the crank throw to the rod. The the oil comes out both holes on the rod journal.

Cross drilling works great up to the critical rpm where the centrifugal force in the cross drilled hole is generating as much pressure as the oil pump, then oil flow pretty much shuts off to the rod. It pulls a hard enough vacuum on the center of the cross drill to cause dissolved gases to come out of solution in the oil and the only oil getting to the rod is foam. If the "event" only lasts for a second or so, the oil film does not completely break down but does allow some contact between the bearing and the rod journal. If it lasts a fraction of a second too long, you spin a bearing and toss a rod through the side of the block.

I found a couple of interesting pictures folks might want to look at, go to Cobbs web site and look at their engine components section

http://cobbtuning.com/wrx/engine-internals.html#rods

-- look closely at their new billet crankshaft, it is NOT cross drilled at the main journals or rods. The crank is carefully postioned so you cannot see how it is drilled, but you can clearly see it is not cross drilled.
(sometimes what you cannot see is as useful as what you can ;) )

If you go to rallispec's site:
http://www.rallispec.com/

Check out their RST-0105 EJ20 (Phase II) STi crank for the 2.0L engine you can see that the oil holes in the mains are not the same as the USDM 2.0 L cranks. It appears to me that they converted the oil drill pattern to the V drill mentioned in the tech paper I posted a few threads ago, but the picture resolution is poor enough that there is a bit of doubt regarding the actual lay out. It is clear that the JDM STi 2.0 L crank is not cross drilled at the mains like the USDM engine but will reserver comment until I get to see one up close and personal.

The Graham Good Racing crankshaft appears it "may" be crossdrilled on the mains but the oil drillings to the rods are clearly re-timed, from the OEM positon.

Ron at Axis power racing does not show a picture of a naked crank on his website ( perfectly reasonable given time he has spent on R&D to come up with his drill layout)

Crawford shows a picture of his cranks but they do not show any useful view of the mains and crank throws other than he uses a one sided oil relief on the main oil feed hole instead of the OEM double relief on the USDM crank.

Likewise the Cosworth crank is also clearly not cross drilled ( or photo retouched to hide the oil drillings as the best photo I've seen of it appears not to have any oil drillings visable from the view provided )

It is clear that everyone who makes big power on these engines is dropping the cross drill USDM OEM design in favor of other drilling patterns. That should tell you something about how to solve rod oiling problems on the WRX.

Larry

Pretty interesting stuff. At what RPM does one need to start worrying about the rod oiling issue? (I'm just curious, I'm stuck with a 6500rpm redline and don't foresee changing that anytime soon).

Pat Olsen
'97 Legacy 2.5GT sedan

response to an old question ---

The key rpm depends on several things, the crank pin diameter ( bigger crank journals reach critical flow at lower rpms). The supply pressure and quality of the oil, and oil supply ( any included air bubbles, ability of the oil to dissolve gases etc.)

On the big block V-8's which typically have slightly larger crank journals than the Subaru, I understand around 8000 - 9000 rpm is where they typically run into problems depending on bearing oil clearence etc, there is no single number.

Larry

do we know for sure that the mains on the JDM 2.0l crank are NOT cross drilled?

do we know for sure that the mains on the JDM 2.0l crank are NOT cross drilled?

They also have all journals cross drilled. I have a 2.0 and 2.5 lying about and they are the same.
The cross drilling of the rod journals is not an issue as they only let oil OUT. It sjust the main journals that have the problem. After all the rod journal is a long way off the centerline of the crank so the centrifugal force acts in its favour.

We were recently able to see the drilling modification of the crankshaft. Basically a third hole is added that unites with the two cross-drilled holes in the rod journals. This hole seems to correspond to near TDC of the piston's travel.

It's unclear that a third opening on the rod journal necessarily leads to more oiling of the rod bearings, but it does provide another path for oil to enter the journal-bearing space.

The need is to have oil entering the rod jounal as quickly as it is leaving. With a cross-drilled crank (like the Subaru) oil will leave the journal as the crank increases its rotational speed, being flung away from the crank. If most of the oil is being flung off of the crank, then a third oiling hole will only make a difference if it is the path of least resistance--something that this drilling modification seems to try and attempt.

Cross-drilled cranks are not the best solution for high speed engines, but to correct the problem posed by suby cranks would require re-engineering of the oiling path thru the crank and that is very expensive.

As far as we know Porsche's very similar crank is not cross-drilled.

Something to think about, the main shuts oil off to pins 1,2,3 at TDC on all 2.5's and non sti 2.0lts.

Mains that supply 1,2,3 pins, the main bearings are not full groove.

Pin oil holes are in the wrong spot too.

All 2.0lt STI engine have 4 oil holes in the mians, 2.0lt wrx, (non sti and 2.5lt engine only have 2 oil holes)

We were recently able to see the drilling modification of the crankshaft. Basically a third hole is added that unites with the two cross-drilled holes in the rod journals. This hole seems to correspond to near TDC of the piston's travel.

It's unclear that a third opening on the rod journal necessarily leads to more oiling of the rod bearings, but it does provide another path for oil to enter the journal-bearing space.

The need is to have oil entering the rod jounal as quickly as it is leaving. With a cross-drilled crank (like the Subaru) oil will leave the journal as the crank increases its rotational speed, being flung away from the crank. If most of the oil is being flung off of the crank, then a third oiling hole will only make a difference if it is the path of least resistance--something that this drilling modification seems to try and attempt.

Cross-drilled cranks are not the best solution for high speed engines, but to correct the problem posed by suby cranks would require re-engineering of the oiling path thru the crank and that is very expensive.

As far as we know Porsche's very similar crank is not cross-drilled.

I agree with you 100%, "cross-drilling" is not the solution.. this is why.

If the oil pump cannot provide enough volume and pressure to overcome the cintrifugal force that pulls oil away from the rod journals (the rod journals oil supply is connected to the main journals oil supply at a location that is not optimal).. Then rod journals are starved of oil.

This cintrifugal force increases with RPM.

So the solution would be to have a correctly designed oil pump for the high RPM application, along with a correctly designed crankshaft for proper oiling.

Both of our billet crankshafts are designed to fix this problem.

- J.

I agree with you 100%, "cross-drilling" is not the solution.. this is why.

If the oil pump cannot provide enough volume and pressure to overcome the cintrifugal force that pulls oil away from the rod journals (the rod journals oil supply is connected to the main journals oil supply at a location that is not optimal).. Then rod journals are starved of oil.

This cintrifugal force increases with RPM.

So the solution would be to have a correctly designed oil pump for the high RPM application, along with a correctly designed crankshaft for proper oiling.

Both of our billet crankshafts are designed to fix this problem.

- J.

if i did not understand cars i would think you were just plugging your crankshafts. you are saying the high volume oil pump with the right crankshaft
would fix the problem. the last sentence of your comment is saying just your crankshafts will correct any oiling issues. ;)

I think I'm going to play with some drilling designs when building my shortblock...man I wish the school would finish our spintron already...

Something to think about, the main shuts oil off to pins 1,2,3 at TDC on all 2.5's and non sti 2.0lts.

Mains that supply 1,2,3 pins, the main bearings are not full groove.

Pin oil holes are in the wrong spot too.

All 2.0lt STI engine have 4 oil holes in the mians, 2.0lt wrx, (non sti and 2.5lt engine only have 2 oil holes)

Hang on a minute.
The rear bearing which is also the crank thrust bearing is full groove. The first and centre mains are not full groove and they do shut off at TDC. I'm not sure why they decided to run a full groove at the rear?

The pin hole's could be better placed but that is not a source of the problem as they only let oil out.

All cranks have full cross drilled journals. There is no difference between sti or 2.5l engine. I know that for sure as I have a number of 2.0 and 2.5L cranks.

And on the subject of drilling an extra hole. This method does not resolve the initial problem of oil starvation. The extra hole is still drilled to the center of the journal. In order to correct for the cross drilling downfall the oil passage must be angle drilled and not pass through the center of the main. Search for for some performance chev crank pics and you will see.
The extra hole is a band aid fix not a solution.

if i did not understand cars i would think you were just plugging your crankshafts. you are saying the high volume oil pump with the right crankshaft
would fix the problem. the last sentence of your comment is saying just your crankshafts will correct any oiling issues. ;)

I just like to share my development and knowledge with the community.
Not sure if you have been following the following thread
http://forums.nasioc.com/forums/showthread.php?t=1062626
They have been getting more in depth on the same topic.
I plan to take pictures and give more details soon.


- Jeremy.

Hang on a minute.
The rear bearing which is also the crank thrust bearing is full groove. The first and centre mains are not full groove and they do shut off at TDC. I'm not sure why they decided to run a full groove at the rear?

The pin hole's could be better placed but that is not a source of the problem as they only let oil out.

All cranks have full cross drilled journals. There is no difference between sti or 2.5l engine. I know that for sure as I have a number of 2.0 and 2.5L cranks.

And on the subject of drilling an extra hole. This method does not resolve the initial problem of oil starvation. The extra hole is still drilled to the center of the journal. In order to correct for the cross drilling downfall the oil passage must be angle drilled and not pass through the center of the main. Search for for some performance chev crank pics and you will see.
The extra hole is a band aid fix not a solution.

You must be looking at the wrong model STI, from 02 JDM and even Aust spec STI has 4 oil holes in the mains, the 2.5 and 2.0lt wrx doesn't.

Has anyone done the sums to see what the pressure is of the oil trying to exit the oil holes at 8000rpm?

Seem time to pull some books out and see if it is quantifiable

You must be looking at the wrong model STI, from 02 JDM and even Aust spec STI has 4 oil holes in the mains, the 2.5 and 2.0lt wrx doesn't.


This is news to me! .
Could someone please post a pic of this

Are you saying only the 2.5L sti has the 4 holes or is it also the 2.0L?

read it again, from 02 JDM and aust spec STI, (that would be 2.0lts) have 4 oil holes in the mains, the 2.5 STI and 2.0lt wrx does not.

some info,
www.msengineering.com.au

bump from the dead to see if anyone has anything new to bring to the table

Bump for more info . So let me get this straight if you plug one of the holes in the main bearings you should be able to supply enough oil to the rod bearing allowing you to safely rev higher ?

about the centrifugal acceleration problem...if you were to plug of the crossdrilled holes on the the main then you would have a radius of the main bearing for one centripal force and then you would the radius from the center of the main to the center (then the cross drilled section) of the rod journal...I would imagine the larger force and acceleration slinging oil away from the main would actually draw oil through...time to actually do some calculations and then test :D

The only way to overcome the centrifugal force is to move oiling point closer to the axis of rotation which means smaller main journals or a whole new oiling system.

Blocking a main journal hole will just lead to less oil entering the crank.

about the centrifugal acceleration problem...if you were to plug of the crossdrilled holes on the the main then you would have a radius of the main bearing for one centripal force and then you would the radius from the center of the main to the center (then the cross drilled section) of the rod journal...I would imagine the larger force and acceleration slinging oil away from the main would actually draw oil through...time to actually do some calculations and then test :D

Why do people have this impression that you can "pull" a fluid, or even suck it? That isn't at all how it works.

What actually happens when you suck on a straw is that ambient air pressure, which is now slightly higher than the pressure in your mouth, pushes the liquid through the straw.

The centrifuge effect will only amount to an "effective" 14.7 psi of oil pressure, at MOST. (probably much less, especially if the crankcase is already under partial vacuum) The oil will then cavitate.

What actually happens when you suck on a straw is that ambient air pressure, which is now slightly higher than the pressure in your mouth, pushes the liquid through the straw.


true but that wouldn't be the case...I should have put sling/slung...
it wouldn't be soo much a straw as a hose:
take a hose, one end with low (or slight negative) pressure feeding it (simulating delta P of the oil at the feed and main) and then you sling the hose around in a circle. Would the force acting on the water/oil in the hose not then pull the oil past the low pressure/negative pressure?...my only worry with this would be that the oil would aerate.
just trying to make the oil go from "low" pressure to "lower" pressure. low is relative.

like I said, I need to run some numbers as this is purely a thought in my head and nothing on paper.

Would the force acting on the water/oil in the hose not then pull the oil past the low pressure/negative pressure?

No, it wouldn't: if you spin a hose with a liquid in vacuum, the liquid in the center of the axis of rotation doesn't even move.

just trying to make the oil go from "low" pressure to "lower" pressure. low is relative.

Low pressure is not relative. We have absolute pressure measurements for a reason. You can't suck a straw in a vacuum.

If the oil, at any point, reaches the center of the crankshaft before going to the rod journals, once the "sucking" force of the oil going to the rod journal reaches 14.7 psi or so, no amount of centripital acceleration, or physical alterations after that point, will increase the flow.

(also, sorry for being blunt, I'm in a bad mood)

(also, sorry for being blunt, I'm in a bad mood)

no biggy, I'm on an extreme lack of sleep and just slapped myself :huh:

not thinking of basic fluid's...:o

The only way to overcome the centrifugal force is to move oiling point closer to the axis of rotation ...

Not necessarily. You just have to keep the oil from being accelerated so soon. The centrifugal "force" is only created by centripetal acceleration, which doesn't exist if the oil isn't rotating.

If the oil path flows in the reverse of the journal rotation, the moving oil won't be spinning as quickly as the journal itself and thus won't experience as much force.

no biggy, I'm on an extreme lack of sleep and just slapped myself :huh:

not thinking of basic fluid's...:o

Oh man, trust me, I know how that goes. I hate days like that! You have my sympathy.

Oh man, trust me, I know how that goes. I hate days like that! You have my sympathy.

yeah, its what 18 credit hours (only 15 after this :D), two jobs and formula sae will do to you :p


so back to coming up with solutions...
new crank with designed oil passages, new oil pump design, dry sump, or...

Not necessarily. You just have to keep the oil from being accelerated so soon. The centrifugal "force" is only created by centripetal acceleration, which doesn't exist if the oil isn't rotating.

If the oil path flows in the reverse of the journal rotation, the moving oil won't be spinning as quickly as the journal itself and thus won't experience as much force.
Have you seen our cranks? The oil has to travel backwards (journal surface toward the axis of rotation) and then back out (away from axis) to the rod journals. The oil is spinning as soon as it enters the crank, and it is being acted on by a centifugal force proportional to the mass of the oil and the RPM of the crank. It requires 80-90 psi just to oil the rods at redline.

Have you seen our cranks? The oil has to travel backwards (journal surface toward the axis of rotation) and then back out (away from axis) to the rod journals.

Don't suppose it looks like this:

http://img.photobucket.com/albums/v14/SaabTuner/EJ_crankshaft_drawing.jpg

So with the 10 psi per 1000 HP figure... and an STI oil pump relief valve set at around 85, I'm good for at least 8k redline?..How much does "shimming" the pump raise the relief to ?

http://img.photobucket.com/albums/v14/SaabTuner/EJ_crankshaft_drawing.jpg

I don't understand this issue where people are saying that the centripedal force must be overcome in order to oil the rods. Others are saying that one of the holes may need to be blocked to stop the oil from flowing out the other hole at the main.

Looking at the physics the path is longer to the rod than to the center of the crank via the main. So will spinning it faster starve the rod for oil? I can see a higher possibility of cavitation yes but the faster you spin it the more the inertia from the longer rod passage will suck.

Also, 2 holes in the main are expected to be subjected to approx the same amount of pressure from the supply channel. I can't see how this would in any way cause the oil to shoot out the other side since both sides should be subjected to the same amount of pressure.

Someone observed that an aftermarket drilled crank had a 3rd hole out the TDC side. To me this makes a lot of sense since the oil will be subjected to more centrifical force (passage is further from the centre of rotation) and it does not need to turn the 90 corner to exit on each side of the rod bearing.

I think someone with too much time on their hands would need to install a crank in a bare block with all the other oil passages blocked, then spin it up to 10,000 rpm and see what happens to the oil supply at different oil pressure levels.

If anything I could see this design starving cylinders 2 and 3 because 1 main feeds 2 rods.

-Michael

The issue is directly due to the "sucking" force you mention (although some on the forum will dispute the use of that term).

You can only pull so hard on a liquid before the fluid column "breaks" this occurs when the suction force on the fluid gets close to the vapor pressure of the fluid, and either boils the fluid, or causes dissolved gasses to come out of solution and make the oil foam. For example you cannot lift water more than about 32 ft with suction (depending on temperature of the water and friction losses in the piping) as the water column will break and the water will flash to vapor under the high suction.

In a cross drilled crank, at high rpm ( usually near 8000 rpm) the oil in the center of the cross drill is under a very low pressure as the centrifugal force trying to throw the oil out of the journal balances the the pressure supplied at the bearing by the system oil pressure. When these forces match oil flow effectively stops. Any bubbles in the oil will expand as they get to the center of the journal, filing that oil channel with foaming oil. At the same time from this low pressure area in the center of the main journal you have the rod drilling which is having the oil pulled up toward the rod journal. This "suction force" to use your term lowers the pressure in the oil enough that it begins to form bubbles of dissolved gasses. This aerated oil has much lower film strength than liquid oil. The net effect is that oiling effectivness to the rod drops substantially. Any high load at this time, like an over rev on down shift or a sharp throttle lift from high rpm, will lead to connecting rod failure as the rod bearing tries to seize an twists off the rod big end, or spins the bearing in the rod.

Larry

The issue is directly due to the "sucking" force you mention (although some on the forum will dispute the use of that term).

You can only pull so hard on a liquid before the fluid column "breaks" this occurs when the suction force on the fluid gets close to the vapor pressure of the fluid, and either boils the fluid, or causes dissolved gasses to come out of solution and make the oil foam. For example you cannot lift water more than about 32 ft with suction (depending on temperature of the water and friction losses in the piping) as the water column will break and the water will flash to vapor under the high suction.

In a cross drilled crank, at high rpm ( usually near 8000 rpm) the oil in the center of the cross drill is under a very low pressure as the centrifugal force trying to throw the oil out of the journal balances the the pressure supplied at the bearing by the system oil pressure. When these forces match oil flow effectively stops. Any bubbles in the oil will expand as they get to the center of the journal, filing that oil channel with foaming oil. At the same time from this low pressure area in the center of the main journal you have the rod drilling which is having the oil pulled up toward the rod journal. This "suction force" to use your term lowers the pressure in the oil enough that it begins to form bubbles of dissolved gasses. This aerated oil has much lower film strength than liquid oil. The net effect is that oiling effectivness to the rod drops substantially. Any high load at this time, like an over rev on down shift or a sharp throttle lift from high rpm, will lead to connecting rod failure as the rod bearing tries to seize an twists off the rod big end, or spins the bearing in the rod.
I think you pretty much explained the problem dead on

The explanation from hotrod above is spot on!
I have been researching the cross drill design and what he says is correct.

I think we have pretty much analysed what is wrong what we need now is some sort of reasonable solution to it.
I dont mean suggestions like fit a dry sump or a setup that costs as much as the bottom end but a reasonable suggestion. Maybe we can investigate getting the crank drilled differently to enhance high rpm oiling. Not only by drilling another hole into the existing cross drilled hole as this doesn't really address the problem but a new passage that doesnt intersect the center of the journal.
Anyone know what other 4 cylinder cranks are using for oiling systems? They all have a 180 degree throw between journals. Take for example a honda inline 4 cyl. They rev heaps thats to the cam system. What are they running?

Lets try to find a practical solution that doesnt mean we have to run extreme oil pressure or dry sumps.

my favorite solution on the crankside is the "v" supply shown in the suzuki paper that was linked earlier in the thread...
aside from that I'm already working on the pump issue. Too bad it costs so much for a poor college kid (only 1 more semester!!) to do out of pocket.

Hi guys,
Here is a picture of our billet subaru crank with improved rod journal oiling.
This is our solution for high power engines. No rod bearing issues. I think
this upgrade is more important than upgrade rods up to 600hp.
Thanks, Tomi

Hi guys,
Here is a picture of our billet subaru crank with improved rod journal oiling.
This is our solution for high power engines. No rod bearing issues. I think
this upgrade is more important than upgrade rods up to 600hp.
Thanks, Tomi

Great pic (once you enlarge it).
You can clearly see the holes going into the crank on an angle. This is exactly what we've talking about.
An oiling system that attempts to reduce the effects of cetrifugal force on the oil. I have no doubts that this crank couples with a well setup standard oil pump will not have any oiling problems whatsoever.
Damn, why didnt subaru do them like this in the first place. Then we could have taken full advantage of the short stroke design and get some serious revs.

Here is another one. Hopefully you can get the idea from this one.
Thanks,
Tomi

Has anyone calculated the vacuum created by the centrifical force to determine if the vapour point of the oil is being crossed? Looking at the billet crank I think the holes look larger but I can't really see how the design itself will do anything to reduce this vacuum.

Another point is that whatever amount of oil pressure finds its way into the crank when raised by only a few psi should make a big difference in this flash boiling if it's even the root of the problem.

I think rather than sitting around as armchair engineers someone needs to do the science to prove or disprove this theory.

From the factory my EJ20K revved to 8250 before the cutoff. The rod bearings showed no sign of oil starvation after a year of kicking the hell out of it and smacking the rev limiter pretty much every day.

I did some googling for the vacuum where engine oil boils but wasn't able to find anything. Even MSDS listed it as "extremely low". So for kicks I hooked up a brake bleeder vacuum pump to a glass coke bottle and wasn't able to see any "frothing" with a drop of mobil1 5w50 at 20C and 50" of Hg. Who knows how accurate this was as it was pretty crude...

I also sent a message to redline oil asking for technical assistance in determining the vacuum point where their oil boils at normal engine operating temp.

My background is not in engineering so maybe those who are educated in this can jump in here.

-Michael

this will be a fun headache on my long list of things to do...
:lol:

I think rather than sitting around as armchair engineers someone needs to do the science to prove or disprove this theory.

You might want to look at the science in the links in my post #31. They spent a bit more time and money figuring out what is going on, than any of us can. I suspect Rehr Morrison spent a few ten's of thousands of dollars on toasted motors on the dyno to come to his conclusion. Given he is one of the premier racing engine builders in the country is a pretty good testiment to his credibility. Add to that the fact the Subaru does not use the crossdrilled design themselves in their JDM STi cranks is worth some thought too.

Larry

After being involved with serious engine r&d program for a long time, we don't use cross drilled cranks on anything.
Subarus are the only ones. (Stage1&2)
First when I got in to this subaru world, this was the first thing I wanted
to improve, and it didn't took a long to come up with this improved
crank. It's kind a pricey upgrade, but very very good one.
Tomi

Now I see what you guys mean about the non-cross-drilled cranks. You don't get one by plugging one of the holes on the main. You get one by drilling the hole from the big end to one of the sides of the main rather than intersecting in the middle.

Reading the article at http://www.tytlabs.co.jp/english/review/rev383epdf/e383_044suzuki.pdf
You can see his research shows that the "v" type oiling system is more effective. This is more of a cross between the two types. Unfortunately I can't see a reasonable cost effective way of "changing" the oiling system on a subaru crank.

For the record I checked my legacy turbo crank and it is cross-drilled. That engine is rumoured to have the highest flowing oil pump of all the subie motors. Does anyone know if it bolts on to let's say an EJ20K?

-Michael

For the record I checked my legacy turbo crank and it is cross-drilled. That engine is rumoured to have the highest flowing oil pump of all the subie motors. Does anyone know if it bolts on to let's say an EJ20K?
all suby pumps are the same...the turbo legacy too...just shimmed from the factory....or so I've been told. Never measured the gears personally.

all suby pumps are the same...the turbo legacy too...just shimmed from the factory....or so I've been told. Never measured the gears personally.

Subaru has two types of oil pumps. I checked them myself and have pulled them apart and measured them.
The difference is the EJ22 type have gears that are 10mm wide, standard oil pumps are 9mm wide. They look identical but the internals are different. This means the EJ22 pump is capable of higher volume.

After being involved with serious engine r&d program for a long time, we don't use cross drilled cranks on anything.
Subarus are the only ones. (Stage1&2)
First when I got in to this subaru world, this was the first thing I wanted
to improve, and it didn't took a long to come up with this improved
crank. It's kind a pricey upgrade, but very very good one.
Tomi

how much is pricey?

Reading the article at http://www.tytlabs.co.jp/english/review/rev383epdf/e383_044suzuki.pdf
You can see his research shows that the "v" type oiling system is more effective. This is more of a cross between the two types. Unfortunately I can't see a reasonable cost effective way of "changing" the oiling system on a subaru crank.

-Michael

Having just read this article the main thing that concerns me about the results is that they are using a bearing shell that has an oil groove only over 180degrees. This is why they get a much more favourable result with the cross drilled main journal.
Add to this they are running at low speed, only 1800 rpms.

I'm pretty sure if they went to a full grooved bearing shell and started to get the revs high enough for centrifugal forces to come into play they would get a different result.

This means the EJ22 pump is capable of higher volume.

The 2.2 also needed to feed the oil squirters which would require more oil flow volume.

Larry

Hey, check out the picture of the Cosworth billet crank.

http://www.cosworth.com/shop_item.php?productid=384

It has oil passages drilled on the 2nd and 4th main journals !!!!
Therefore you would have to drill the block and get grooved bearing shells. Surprising since the 2nd and 4th bearings are already so narrow, the groove would further reduce surface area.

Is this the same item as on the Cobb website? The design looks identical. I wonder who actually manufactures the thing?

Our 75mm or 79mm stroke billet crank is $1149, 00.
Thanks,
Tomi

Subaru has a number of different oil pumps:

7mm lastest EUDM SOHC engines
9mm all the older EUDM SOHC engines
10mm all the turbo engines and EJ25 engines (part# AA104~108, AA280)
12mm JDM dual AVCS engines

The size above refers to the width of the throchoid gears inside the pump. If the stock 10mm pump is set at 100%, then you can say the 12mm pump flows 20% more oil. These 12mm pumps are a cheap upgrade compared to the JUN, Cosworth and who-knows-what pumps. The size of the pump is stamped on the left side above the crankshaft sprocket. It's visible with the belt covers installed.

The SOHC pumps run at 5 bar oil pressure, the Turbo and DOHC pumps at 6 bar.

All pumps are interchangable.

Our 75mm or 79mm stroke billet crank is $1149, 00.
Thanks,
Tomi
well, I think you will have 2 cranks orders coming in a little down the road.


also quite interested finding the width differences in the pumps.

That's a pretty cheap billet crank (relative to others). I may have to get one of those....hm.....



also, the 12mm Jdm oil pump seems like a winner.


We need to find out what size the cosworth and Jun pumps are.

How expensive would it be to get the JDM pump....probably lots of money huh?

Our 75mm or 79mm stroke billet crank is $1149, 00.
Thanks,
Tomi


The price is certainly a lot less than the typical $3000-$3500 that crawford and Cosworth are asking, however I am yet to see any real information on these cranks.

Personally I'd like to know more such as-
Why are these so much cheaper.
What grade of steel are they made of.
What oiling system do they use (very important given our problems).
What tests are done on the material to ensure it's integrity ie;magnafluxing.
What hp do they rate at or have been tested to.
What processes have they gone through (if any) ie;nitriding, peening

A crank can cause a lot of damage if it breaks. I'd want to be more confident before using one.

Speaking of oil pumps I've hand ported a large number of honda pumps. I won't go into what I do but the changes are very minor.

I built a test bed to measure flow. With cold oil they flowed almost 20% more. Hot oil the increase was more like 8% but it gives you an idea how inefficient the pumps were.

I didn't have a way to measure the amount of power required to run the pump but I did have some trouble slowing the ported pump down to the same RPM to make accurate measurements. This told me it required less power to run.

Subaru engines are my personal interest but it would be interesting to pull a pump apart and see how efficient the flow is through the casting. I'm willing to bet it could be improved.

-Michael

Here is some details about our billet crank:
- 4340 billet
- Core hardened and nitrated
- Every crank is magnafluxed
- You can call that oiling "straight shot" (Crower trademark though...)
- Hard to say how much hp cranks can take, depends on rpm and so on,
but let's say about 1000hp easy.

I do have 3 cranks left for super cheap price ($1149), then price goes up
to $1299 thanks for strong EURO current.

This is a high quality peace, don't let the price fool you!

Thanks,
Tomi

just measured my old EJ18 pump and it is 8.84mm
need to get a used turbo oil pump to start checking out...see what room is left.

How would you even order the JDM oil pump...I mean are there JDM new parts dealers? I have only seen used JDM oem parts on the market. Seems like it would be a reasonable upgrade compared to the $1000 I have seen for some of the high volume oil pumps on the market out of Japan. While I am not really planning on reving my engine past 7.5k in my hybrid build, a little added security is always nice. Also which years and models had dual AVCS?

How would you even order the JDM oil pump...I mean are there JDM new parts dealers? I have only seen used JDM oem parts on the market. Seems like it would be a reasonable upgrade compared to the $1000 I have seen for some of the high volume oil pumps on the market out of Japan. While I am not really planning on reving my engine past 7.5k in my hybrid build, a little added security is always nice. Also which years and models had dual AVCS?

I emailed japanparts a NASIOC vendor, this:

Graham,

My name is Ryan and I am wondering if you can get an oil pump that came off of JDM engines with DUAL AVCS cams. Im not sure the specific engine....I was told any engine with DUAL AVCS. The gears are 12mm compared to our 10mm. Evidently the numbers are stamped on the cover? or something. Please reference this thread...post #99 http://forums.nasioc.com/forums/showthread.php?t=956862&page=4

We are in the market for these oil pumps, and would like to know price and availability for them...including shipping to the U.S. If you cannot get these or have any other questions, please let me know.

Thanks for your time,

Ryan

I emailed japanparts a NASIOC vendor, this:

Graham,

My name is Ryan and I am wondering if you can get an oil pump that came off of JDM engines with DUAL AVCS cams. Im not sure the specific engine....I was told any engine with DUAL AVCS. The gears are 12mm compared to our 10mm. Evidently the numbers are stamped on the cover? or something. Please reference this thread...post #99 http://forums.nasioc.com/forums/showthread.php?t=956862&page=4

We are in the market for these oil pumps, and would like to know price and availability for them...including shipping to the U.S. If you cannot get these or have any other questions, please let me know.

Thanks for your time,

Ryan

I've done the same with my importer.
I'll share what I find out.

anyone know if cobb modifies the oil passages in thier built blocks?

anyone know if cobb modifies the oil passages in thier built blocks?

Im not sure....but tomorrow i am calling Cobb because I am very interested in their stage 2 engine....possibly their stage 3 tuner series......

Cobb's price for their "tuner" series billet crank is on par with TJL's. Their website says that it is "cross-drilled"
http://cobbtuning.com/products/?id=2267

I've done the same with my importer.
I'll share what I find out.

I actually looked on their site and did not see any mentioned other than the $924 JUN high flow. I did contact JDMspec4U. They are another importer here on nasioc. I'll let you guys know what I find. This info is really coming at a good time as I am in the middle of getting all the parts for my 2.5 swap.

Add to that the fact the Subaru does not use the crossdrilled design themselves in their JDM STi cranks is worth some thought too.

Larry

You must be looking at the wrong model STI, from 02 JDM and even Aust spec STI has 4 oil holes in the mains, the 2.5 and 2.0lt wrx doesn't.

Has anyone done the sums to see what the pressure is of the oil trying to exit the oil holes at 8000rpm?



OK. I just re-read the thread. Am I missing something? larry is saying that the JDM cranks are NOT crossdrilled...meaning....a hole that goes through the mains....straitht through....thus 2 holes in the crank....180 degrees apart.

MSR is saying that it is cross drilled....twice?

confused? :confused:

All I know is I have been told by professional engine builders that the crank drilling is different in the JDM STi cranks, but have never been able to find someone who can discribe the exact difference or a good picture of them.

I think it was Rallispec used to have a picture of a JDM sti crank and it was obvious the drilling was different as you could not see the holes in the normal USDM location but I never found a picture with a good view of the journals to determine "how" it was different.

Larry

I've been reading this thread and the other thread and I was browsing through some of my pictures and came upon these. I completely forgot about them. These are pictures of a crank from an Axis Stage 3 short block.

Looks like he did some modifying of the oil holes.

I'm just adding to the conversation as I'm completely lost on what to do. Everyone in this thread is saying that we have to do something to the oiling system, but I also have a VERY reputable tuner on here that runs his STI out to 8300RPM without problems....stock oil pump, stock bearings, stock bearing clearances, Pauter rods, CP Pistons. They tore two motors down around 15,000 miles each and the bearings were still in good shape.

http://img.photobucket.com/albums/v295/SloRice/DSCN1227-2.jpg

http://img.photobucket.com/albums/v295/SloRice/DSCN1225-2.jpg

I've been reading this thread and the other thread and I was browsing through some of my pictures and came upon these. I completely forgot about them. These are pictures of a crank from an Axis Stage 3 short block.

Looks like he did some modifying of the oil holes.

I'm just adding to the conversation as I'm completely lost on what to do. Everyone in this thread is saying that we have to do something to the oiling system, but I also have a VERY reputable tuner on here that runs his STI out to 8300RPM without problems....stock oil pump, stock bearings, stock bearing clearances, Pauter rods, CP Pistons. They tore two motors down around 15,000 miles each and the bearings were still in good shape.


I have heard the rpm rumor also. But they have more money than us ;)

IN the top picture (sorry, no pun intended) but it looks as if the drilling didn't work :lol: spun rod bearing much? What was the root cause of that engine failure?

In the bottom pic, is that the main jounal on the top, has been re-drilled?

OK, I retract my statement from my last post. I just went out to the garage and looked at a stock STI crank and the oil holes in that crank look the same.

As for the first picture.....it was a completely different reason it spun a bearing, not RPM.

In the second picture, on the far right, that is the front main journal.

Also, that 8300 RPM statement in my last post came from an avid road racer, so you know it's seeing that RPM for long periods of time.

OK, I retract my statement from my last post. I just went out to the garage and looked at a stock STI crank and the oil holes in that crank look the same.


The oil holes in the stock sti crank: 2 holes on the mains, and 2 holes on the rod journals...180* apart from eachother, correct?

The pics above don't show the holes 180* apart. it looks like extra holes have been drilled in the mains and rods, no?

this was taken from the "JDM and EUR speck BONANZA" thread:



As with the JDM market, the 02 WRX crankshaft was updated, and all MY03 and greater WRXs use this new crankshaft. I personally observed that my 02 Spec C crank was double drilled, while my stock WRX crankshaft was single drilled. I suspect the double drilling may have been the change from (0x210) to (0x240). Anyone with an 04 or 05 WRX crank could confirm this.

12200AA210: MY02 WRX
12200AA240: MY02,03,04,05 WRX [UPDATED]
12200AA260: MY04,05 STI

JDM Overlap:
WRX Crankshaft is same as JDM MY01-05 WRX crankshaft, as well as the JDM MY01,02 STI crankshaft.

Well, I don't have the Axis crank available to see right now. But in a few days, I will have this crank and a stock crank side by side and we'll take a look at the differences.

I actually looked on their site and did not see any mentioned other than the $924 JUN high flow. I did contact JDMspec4U. They are another importer here on nasioc. I'll let you guys know what I find. This info is really coming at a good time as I am in the middle of getting all the parts for my 2.5 swap.

who's site? my importer doesn't have a site...:confused:

Interestingly it looks like someone was checking clearances in the top pic. Looks like plastigauge on the mains...

Here is the response I got from Redline oil:


> This problem only occurs when the motor has been
> modified and run to higher than normal RPMs. 9000+.
> I am looking for the amount of vacuum before
> cavitation occurs at a given temperature.

What you want to use is a low viscosity oil and compare low NOACK volatility numbers.

-Michael

Not sure if these have been posted before but here are a couple of pics of the 2.5L Cobb "Tuner Series" Crank. This one is set to go into my new block build, 2.2T closed deck case, Darton Sleeves, Pauter Rods, 100mm Coated CP's, ACL Race Bearings....

http://www.mickandsarah.com/wrx/Cobb-Tuner-Crank/images/img_0948.jpg

http://www.mickandsarah.com/wrx/Cobb-Tuner-Crank/images/img_0954.jpg

All Pics http://www.mickandsarah.com/wrx/Cobb-Tuner-Crank/index.html

wow, all your pics look harsh. The crankshaft journals are still covered in oil.
Clean it up and show off that polish :banana:

I need to post the pics that Brian Crower sent me of his.
Looks the same as cobb's from what I can tell...everyone seems to be doing a straight through.

cheers to all involved for a very good thread.

this was taken from the "JDM and EUR speck BONANZA" thread:


Originally Posted by PDXTuning

As with the JDM market, the 02 WRX crankshaft was updated, and all MY03 and greater WRXs use this new crankshaft. I personally observed that my 02 Spec C crank was double drilled, while my stock WRX crankshaft was single drilled. I suspect the double drilling may have been the change from (0x210) to (0x240). Anyone with an 04 or 05 WRX crank could confirm this.

12200AA210: MY02 WRX
12200AA240: MY02,03,04,05 WRX [UPDATED]
12200AA260: MY04,05 STI

JDM Overlap:
WRX Crankshaft is same as JDM MY01-05 WRX crankshaft, as well as the JDM MY01,02 STI crankshaft.



Here is a shot of a Version 7 RA Spec C crank:

http://www.sponaugle.com/nasioc/SpecC-crank1.jpg

http://www.sponaugle.com/nasioc/SpecC-crank3.jpg

As you can see, this factory crank (rated to 8300 rpm from Subaru) uses the dual drilled oil feeds on all three case surfaces.

Jeff Sponaugle

Where does the rod journal drilling intersect the two holes? Near the surface of the main journal or in the center of the main journal like the OEM cross drilled crank?

Do either of the double drilled holes go all the way through the crank journal as the cross drilled do, or do they meet more or less at 90* to each other as blind holes?

Larry

Where does the rod journal drilling intersect the two holes? Near the surface of the main journal or in the center of the main journal like the OEM cross drilled crank?

Do either of the double drilled holes go all the way through the crank journal as the cross drilled do, or do they meet more or less at 90* to each other as blind holes?

Larry

This is an OEM JDM crank, so the holes go all the way thru the journals. The rod journal holes intersect at the center, so the only real difference from this crank to the US WRX one is the extra complete thru hole drilled in each journal. (in other words, at the bearing surface there are 4 total holes instead of two).

Jeff

From these stock parts and the revision on the WRX crank I wonder what subaru knows that we don't. The extra holes, while inexpensive to drill do not combat the centrifugal force rumoured to cause aeration. They may, however provide more absolute flow to the hole that passes to the rod bearings. I can see this as an advantage on the #3 main which feeds rods 2 and 3. Can anyone say which rods are more likely to spin a bearing?

Considering it would be the same additional setup when they machine the OEM cranks it's possible that the extra holes were added to the first and last main as an extra for minimal cost even though the engineering solution only required #3 to be drilled.

-Michael

. I can see this as an advantage on the #3 main which feeds rods 2 and 3. Can anyone say which rods are more likely to spin a bearing?

Considering it would be the same additional setup when they machine the OEM cranks it's possible that the extra holes were added to the first and last main as an extra for minimal cost even though the engineering solution only required #3 to be drilled.

-Michael

The 2nd and 3rd rod journal are the most common failures, the reason being pretty obvious. Only one main journal to feed 2 rod journals. Whereas rods 1 and 4 both are supplied by their own main bearing hence getting better oil supply.

This thread is WAY over my head but I have a question. Any thoughts on what to do with a phase1, 2.5L crank? Ron at Axis will "mod" and balance but is it worth the $ I'm building a 2.35L from an ej22T and have ordered a 12mm oil pump. I plan to use the oil squirters. I will definatly have everything balanced and will gladly pay Ron to cross drill the crank for added peace of mind but is it the best thing to do?

I'm going to be building that same engine and yes I will be drilling my crank plus porting the oil pump and possibly even re-shimming it for slightly higher pressure.

I tune engines for a living so I'll definitely be more aggressive than most and if it expires it's not a huge deal. In my opinion if you're going to push an engine hard you should do every cost effective thing you can to ensure its longevity. A spun bearing is an expensive problem so I'd say definitely a good idea.

-Michael

I added an update on the other thread about the 12mm oil pumps FYI:

http://forums.nasioc.com/forums/showthread.php?p=16992686&posted=1#post16992686


Jeff

I am trying to wrap my head around this topic. The way I understand it, you'd want more holes to the #2 and #3 rod journals since they are the weakest link. It also seems like you would NOT want any more holes drilled to the other journals since they never seem to fail and adding holes there would just increase the chances of oil flowing out of them which would in turn reduce oil flow out of the #2 and #3 rod journals. Also, cleaning up the oil pump to make passages smoother to improve flow is a good idea.

What about the guy running up to 8300rpms on a stock crank oiling system on a road course?
Would simply increase flow/efficiency of the oil pump help this bearing problem tremendously?
Subaru doesn't seem to think that centripetal force is a big problem. In fact, by adding more holes to the JDM crank, they are making it easier for oil to flow to the rod journals due to centripetal force.
What is a good fix to the USDM WRX/STi crank to rev higher?

Please add/correct info.

Why is it a problem for us to drill the crank the same as the JDM 2.0l? Isn't that redline at 8k or beyond?

12mm oil pump FTW too!

well, some of us want to go well beyond 8k :devil:


those damn honda's are rubbing off

anyone know if the phase 1 and 2 cobb blocks used modified cranks?

I am trying to wrap my head around this topic. The way I understand it, you'd want more holes to the #2 and #3 rod journals since they are the weakest link. It also seems like you would NOT want any more holes drilled to the other journals since they never seem to fail and adding holes there would just increase the chances of oil flowing out of them which would in turn reduce oil flow out of the #2 and #3 rod journals. Also, cleaning up the oil pump to make passages smoother to improve flow is a good idea.

What about the guy running up to 8300rpms on a stock crank oiling system on a road course?
Would simply increase flow/efficiency of the oil pump help this bearing problem tremendously?
Subaru doesn't seem to think that centripetal force is a big problem. In fact, by adding more holes to the JDM crank, they are making it easier for oil to flow to the rod journals due to centripetal force.
What is a good fix to the USDM WRX/STi crank to rev higher?

Please add/correct info.

All the rod journals starve at high speed. The oil gets flung out of the rod journals due to centrifugal force, but oil entering the main journal holes has no centripetal force to pull it into the crank. The oil leaks past the main bearings instead of going thru the crank to the rod bearing.

The problem is the distance from teh crack axis to the main journal surface. The oil has to flow "backwards" agains the centrifugal force. It's only an inch or two, but at high RPM it's enough to cause problems.

On top of all this oiling, detonation damages the rod journals first by smashing them TDC (ouch!). Now you are even more likely to spin a bearing with even minimal oil starvation.

The rod journals are most definately cross-drilled, but the drilling mod or the Spec C crank add a third hole that connects with the cross drilled ones like a 'y'. The third hole is drilled at such an angle and placement that oil is released from the new hole just prior to TDC, right at it's worst centrifugal time period.

The cross drilled holes on the other hand are drilled so that they are perpendicular to the force vector, or put another way, tangent to the circular motion of the crank.

So what would help increase lubrication at 8500rpms more. Increasing the number of shims in the oil pump to bump up the oil pressure or drilling another thru hole through the rod journals (like a JDM non-spec-C crank).

Again, correct anything in this post that is incorrect.

time to bring it back to life...
did some smokey yunick reading on oil and he had said the best oil delievery is to cross drill the crank and block off the oil by-pass...block off so long as you have a race oil filter that won't rupture...
the cross drilling makes sense in that it keeps the bearing riding on a constantly higher pressure oil layer because of the more often oil delivery. It also retains a better wedge.
I disagree with completely blocking off the by-pass as that will lead to a loss of power once crossed the needed oil pressure.

The spec c crank in the 05 model doesn't have the under cut radius on the pins and mains, it has a radius that starts from the bearing suface to the edge, same size, just not an under cut one, they also come Nitrited, look "grey" all over.

This may sound totally strange, but how do motorbikes rev to insane levels and happily do it all day long without issue !? Power wise, some of the liter bikes are nudging 200HP/L, not dissimilar to some modified suby engines. Does this not debunk the oil breaking down/foaming at high rpm theory, or are bikes engineered differently!?

That's a pretty cheap billet crank (relative to others). I may have to get one of those....hm.....



also, the 12mm Jdm oil pump seems like a winner.


We need to find out what size the cosworth and Jun pumps are.

How expensive would it be to get the JDM pump....probably lots of money huh?

Yes, this Part costs an Arm and a Leg ;)

http://forums.nasioc.com/forums/showthread.php?t=1263180

Best

GW
Japanparts LLC
* Since 1996 *

How would you even order the JDM oil pump...I mean are there JDM new parts dealers? I have only seen used JDM oem parts on the market. Seems like it would be a reasonable upgrade compared to the $1000 I have seen for some of the high volume oil pumps on the market out of Japan. While I am not really planning on reving my engine past 7.5k in my hybrid build, a little added security is always nice. Also which years and models had dual AVCS?

Thanks to Jeff Sponaugle for his assistance with the Part numbers;

12mm Pump is: -270 Part number

http://forums.nasioc.com/forums/showthread.php?t=1263180

We're 3 doors up from a Subaru Dealership in Tokyo and have been exporting parts since 1996; Subaru parts that left our warehouse this week went to 17 Countries, including Kazakhstan, Swaziland, South Africa, Belize, Moldova, Antigua and even ... *gasp* North America....

Best

GW
Japanparts LLC

************************************************** ********

This may sound totally strange, but how do motorbikes rev to insane levels and happily do it all day long without issue !? Power wise, some of the liter bikes are nudging 200HP/L, not dissimilar to some modified suby engines. Does this not debunk the oil breaking down/foaming at high rpm theory, or are bikes engineered differently!?

the problem comes in the oil delivery...has nothing to do with the hp/l.
Also keep in mind that when those motors are made at the factory they are designed for high RPM's...subie motors, well not so much ;)

So I guess this would be considered an oil delivery problem. :mad: I was tracking the car on a road course to 7300 rpm. I just spent the last hour reading the last six pages, very interesting. I'm still trying to figure which direction to go without spending 3k plus on a crank. I'm thinking about an axis modded crank, 12mm JDM oil pump, massaged oil galleys, Moroso pan, and drain back lines from valve covers. Any other thoughts?
http://i138.photobucket.com/albums/q254/yzblazr/411-1186_IMG.jpg

Well first of all, are all the pistons like that or only this one?

Do the other rod bearings show that they lost oil pressure?

You'd have to figure out what the mechanism of failure was.
It could be oil pressure failure (which should show scoring and damage on all the rods, and other bearings), it could be isolated only to this cylinder.
It could be detonation damage pounded this bearing out and then it failed.
Lots of possibilities.

Do you have scoring on the cylinder wall, it looks like the piston siezed in the bore and the rod tried to yank out the bottom of the pin boss. That could be due to broken rings grabbing the cylinder wall.

Interesting failure for sure.

Larry

^^^ Holy mother of...!? :eek:

Like Larry said, if only the one I'm guessing det...
-Micah

Larry, first off thanks for your reply. I am a longtime engine builder for the SCCA Trans/Am series and now the Rolex Daytona Prototype series. I've seen many engine failures. "I just never thought it would happen to me" (how ironic). I was being facetious with my "I guess this would be an oil delivery problem" comment. I do believe it was. It was a 98 deg day at CMP and temps were quite high, which I'm sure didn't help. This happend after a long
3rd gear sweeping right (210deg.), 4th to 5th straight, then forth gear sweeping right. I would think a lot of oil built up in the left valve cover without good drainback and left the pan low of oil. It was either this or the inherant crank problem, except for turning only 7300 rpm. It was rod #3 that failed with #2 not far behind. No sign of detonation, all cyl walls look fine, and #1 and #4 rods look good. I still want to address the inherant crank issues, drainback, and oil capacity. I could probably build a dry sump system for less than others due to parts availability, but that seems like overkill. I've also noticed that any pumps I've seen were mounted in place of the AC unit. I don't want to lose the AC. I've always been an american v-8 person, thus still learning all this Suby stuff. Any thoughts and suggestions are definitely appreciated. Thanks to all
http://i138.photobucket.com/albums/q254/yzblazr/411-1191_IMG.jpg
http://i138.photobucket.com/albums/q254/yzblazr/411-1192_IMG.jpg

After reading this thread, I think I will be doing like the ver 7 specC crank. Double drilled (4x holes 90 degrees apart) oil feeds on all three case surfaces, on all four rod journals and the 12mm pump.

Post #126 for pictures.

What do you guys think?

This happend after a long
3rd gear sweeping right (210deg.), 4th to 5th straight, then forth gear sweeping right. I would think a lot of oil built up in the left valve cover without good drainback and left the pan low of oil.

I think you nailed it with that sentence. With your engine building racing back ground I'm sure you can read all the signs that will tell you what failed first etc.

The flat opposed engines have inherent oil drain back problems at high rpm. Heck even a V-8 has oil drain back problems at high rpm, it is easy to suck the pan dry or at least low enough to pull a slug of air with the oil pickup. I think serious engine builders should take a look at doing some detail work on the heads and oil drainback passages, and oil shedding coatings on the valve cover sides of the heads to speed oil return.

I wish there was an affordable, properly baffled, over size sump oil pan for our engine as it would make a nice intermediate step between the dry sump system, acu-sump setup, deep sump pan, stock pan.

An external oil cooler with high oil capacity and a swirl tank to get air out of the oil would be another option. I understand that oil coolers are popular in Japan on the high perf subaru's --- wonder if they know something we should? An external oil cooler is a simple way to increase your total oil supply.

The other thing I thought of, would be a semi-dry sump which fits a simple scavenge pump plumbed to the bottom of both valve covers, that pumps oil out of the valve covers into a swirl tank to get the air out and then into the pan.

That rod big end certainly got toasty hot so I think your diagnosis is right on. An improved crank would certainly help but personally I think the primary issue is oil drain back and oil management in the sump for you guys that do track days. For a stock car the oil pan is pretty good, but a big kickout on the side of the sump and an additional 1 inch depth on the sump would go a long way toward keeping the oil pickup from sucking air on a hard turn.

Larry

An external oil cooler with high oil capacity and a swirl tank to get air out of the oil would be another option. I understand that oil coolers are popular in Japan on the high perf subaru's --- wonder if they know something we should? An external oil cooler is a simple way to increase your total oil supply.

It will increase the volume of oil, so instantaneous heat loads will be less of a shock, not that this is ordinarily a problem with oil anyway. Sucking air will still be sucking air, pressure will drop regardless.

I always liked the idea of using scavenge pumps to fill an external tank that the stock oil pump pulled from, but at that point you may as well go "normal" dry sump.

I am building a street scrambler. a manx style dune buggy with a subie. My son has a hot rod STI so we are studying subie hot rodding. I don't have racing experience but I can fab and shade tree engineer. Kennedy engineering sells a short pan for this application. I bought their pan parts and two sbc chev. cheater kits from speedway motors and built a pan with three swinging gates for more volume and to prevent oil starvation on corners and launch. We are so happy to get 12mm pumps. I will never build a subie without doing as much as I can to improve oiling. I would never dream of extended 7000 rpms on any production motor without improving it. The winged bottom from Kennedy seems to hold 6 quarts buy itself and if you made it the stock depth the pan might hold more than 9 quarts. of course the pickup would need to be adjusted to be about a half inch off the bottom. I'm not sure about how far off the bottom because of the 12mm pump volume. I migged mine but it will look better tigged. Also the dip stick is brazed or silver soldered on but that won't concern stock depth modification. I don't think drainback would be a problem with this pan. Also I use a Accusump on my street blazer for 5000 rpm jaunts but it takes up a lot of space. Just study any circle track application for oiling improvements. I sure appreciate all the quality discussion this forum provides, thanks
Charlie

I am building a street scrambler. a manx style dune buggy with a subie. My son has a hot rod STI so we are studying subie hot rodding. I don't have racing experience but I can fab and shade tree engineer. Kennedy engineering sells a short pan for this application. I bought their pan parts and two sbc chev. cheater kits from speedway motors and built a pan with three swinging gates for more volume and to prevent oil starvation on corners and launch. We are so happy to get 12mm pumps. I will never build a subie without doing as much as I can to improve oiling. I would never dream of extended 7000 rpms on any production motor without improving it. The winged bottom from Kennedy seems to hold 6 quarts buy itself and if you made it the stock depth the pan might hold more than 9 quarts. of course the pickup would need to be adjusted to be about a half inch off the bottom. I'm not sure about how far off the bottom because of the 12mm pump volume. I migged mine but it will look better tigged. Also the dip stick is brazed or silver soldered on but that won't concern stock depth modification. I don't think drainback would be a problem with this pan. Also I use a Accusump on my street blazer for 5000 rpm jaunts but it takes up a lot of space. Just study any circle track application for oiling improvements. I sure appreciate all the quality discussion this forum provides, thanks
Charlie

Start your thread and show us some pictures of the pan you're building. :cool:

Also the 12mm oil pump fits perfect with the crank and all?

Im looking forward to seeing if the volume increase of the 12mm pump (since it's a bandwagon thing now) will have negative effects on road coarse racers with extended high rpm's. Just because of the drainback issue with our heads already.

Nothing like pumping all that oil into the cams...and not having it drain back for the mains/rods.

Very interesting subject... ;)

Anybody with experience on an Axis modified crankshaft?

On a newly built Axis shortbloc stage 3 (1500 miles, 300 miles for tune), we have a failure on two rod bearing (#2,#3), fortunately we stopped the engine just in time

Image at http:
img502.imageshack.us/img502/1303/rod21dl1.jpg
img354.imageshack.us/img354/4435/rod22no4.jpg
(sorry not possible to attach them :( )

We dont understand what could occur on this case :confused: (we do more hp with stock 2.5L STI crankshaft without any problem)

when you are breaking pieces out of the bearing metal like that it usually means it was a fatigue failure of the bearing (it was being pounded by detonation most likely given its location at TDC on the big end.)

Larry

Hi Larry,

Thanks for your reply ;-)
No knock, we've used a detcan and we tune with PowerFC (with stock engine knock sensor - max noise level: 9 , no peak) - pistons head are clear, no knock trace

The hole in the bearing is timed approx 18-20° after the TDC, like the additional hole of lubrication on the crankshaft when the peak cylinder pressure occur

On a tune point of view, we have 13° at the end of spool (4000) up to 23° at red line (7000), no knock, is this excessive timing (it's only poor fuel, only RON 98)? I don't think, I use this timing on another engine without any problem

I would think knock was a factor also. Knock is a HUGE killer of subie bearings.

What was your Air/Fuel ratio?

GT35R with FMIC

AFR 11:1 in end spool zone, 11.5:1 after (4000-7000) and no knock
EGT no more 910°C

GT35R with FMIC

AFR 11:1 in end spool zone, 11.5:1 after (4000-7000) and no knock
EGT no more 910°C

http://img502.imageshack.us/img502/1303/rod21dl1.jpg

http://img354.imageshack.us/img354/4435/rod22no4.jpg



there you go!!

If you had no knock than I would suspect excessive bearing clearences, that allowed the rod to pound the crank journal when it began the power stroke, over advanced timing. ( any chance your indicated timing and your real timing or different?)

Poor bearing fit in the rod so it could move around a bit.
( do you see any fretting on the back of the bearing?)

You might want to send those bearings back to the manufacture and see if their tech support people can give you a better idea what happened.

Those are the only things that I can think of off the top of my head why the bearing would delaminate like that.

Have you miked the rod journal on that throw to be sure it is round, and to spec?

Any chance you mixed rod caps between two rods so you had really weird bearing clearence in that rod?

Larry

I never really thought our stock oiling system was so poor ....

its sad to think that a simple hard left to hard right turn with some acceleration would be enough to cause the oilpan to drain enough to suck air...

so an external oil cooler is some help eh? is this more because it increases oil capacity(to have MORE oil in the pan at once) or due to the fact the return line would be draining back right near the oil pickup ?

its sad to think that a simple hard left to hard right turn with some acceleration would be enough to cause the oilpan to drain enough to suck air...


Its more complex than that, it also requires extended time holding the engine at high rpm with out any significant throttle lifts, and perhaps a bit of oil level drop due to blow by.

All engines have this problem and common passenger car engines are simply never designed to provide oiling under these conditions. Back in the 1960's this was common in Detroit V-8's used in road racing and similar situations. The SBC (small block Chevy) would pump all the oil in the valve covers at about 6000 rpm on a drag strip pass if you hung it at high rpm a bit too long.

That is why you can buy after market deep oil pans for all common performance engines.

It is just one of those problems that comes with the territory if you track your car, unless you buying a high end sports car that is designed with this sort of use in mind.

Larry

If you had no knock than I would suspect excessive bearing clearences, that allowed the rod to pound the crank journal when it began the power stroke, over advanced timing. ( any chance your indicated timing and your real timing or different?)

No, I tune very conservative at beginning, and add 1 or 2° until hearing or see knock noise...

Poor bearing fit in the rod so it could move around a bit.
( do you see any fretting on the back of the bearing?)

No fretting in the back of the bearing, no hot zone, it's look very clean

You might want to send those bearings back to the manufacture and see if their tech support people can give you a better idea what happened.

Good idea ;)

Have you miked the rod journal on that throw to be sure it is round, and to spec?

No, not for the moment... I will do that

Any chance you mixed rod caps between two rods so you had really weird bearing clearence in that rod?

No, all caps are in place, it's a newly shortbloc assembled by Ron (Axis)

Thanks for all, Larry

I fully understand the perils of tracking the Subaru and while some say that my engine failures are from detonation I see the #1 cause as oil starvation.

Which is why my new build has a dry sump with accusump backup. If I kill another engine in the same way (rod bearing failures) then Ill blame my tuning :)

At Portland International Raceway you spend most of your time in high G corners. The fact that oil is being forced out of the valve cover vents tells me that the oil pan is getting low. Once in a while I would see flutters in the oil pressure, very quick and until my last failure I just ignored them. Now I understand what they were. I would bet that it was air being sucked into the pump. A moment loss of oil pressure and at 6000 rpm at 400+ WHP that's going to hurt the bearings.

In addition to the dry sump and accusump I've used the Cobb tuner crank which has better oiling and I left far more clearance in the main and rod bearings to improve oiling. The dry sump pump will be able to flow enough oil and maintain pressure.

Anyway, that's enough for now.

bump to help my friend cpdlx find out what happened :)

No, all caps are in place, it's a newly shortbloc assembled by Ron (Axis)

This is exactly how Nick's engine failed, and was a built motor from Axis. Hmmm ... I wonder if Ron might have forgotten to plasti-gauge a few motors here and there when doing the bearings.

When doing the Formula Ford, a different Nick (old friend of mine since I was a kid) and I had to send back our bearing sets 2 times because they were out of spec. I guess 3rd set is the charm. :lol: If we hadn't, we'd be like about half the other race teams out at Buttonwillow, DNF'ing on the first race with a blown motor and a big hole in the block where the rod kicked out. :eek: And it's not always easy to find a good Cortina block lying around anymore, so they can be a hassle to replace properly- makes me glad we checked, re-checked, and then checked again BEFORE running the motor. ;)

I say you call up Ron and ask what he thinks, since he assembled it, then put your thoughts about all of it into the feedback thread about axis a few threads down/up from this one. :)

It may just be the photo but it looks like the fragment didn't wipe all the way around the insert, just like maybe the insert was bigger than the rod journal and only touching on the up and down or the big end of the rod is not round. just my observation.

Charliew

I have blown up two motors with detonation. I'm not proud of it, but I would bet money that the bearings in modaddicts picture are pitted because of detonation. It's the location of the pits that makes me believe this. If you plotted where those pits are, I'm betting its shortly prior to TDC right after the spark.

Mick you are a fantasic guy and I love your contibutions, but I disagree with your starvation model for PIR. Lots of cars drove that track the same day with the same Suby oil pan and had no trouble. No doubt Suby's starve in high g's but not that day.

Trent

Great info Trent, I read an article I think in an aussie web magazine, I think its autospeed, where it shows how to build an audio device to listen for detonation and the author swears you can hear better than the stock knock sensor. The cost was less than 20.00, it's a modified cheap hearing device. Come to think of it I would probably enjoy more tv and movies if I had two. It seems it could be used as a secondary feedback especially when dynoing. This maybe a dumb question but can you calibrate the knock circuit for sensitivity?

Charliew

Once in a while I would see flutters in the oil pressure, very quick and until my last failure I just ignored them. Now I understand what they were. I would bet that it was air being sucked into the pump. A moment loss of oil pressure and at 6000 rpm at 400+ WHP that's going to hurt the bearings.

I would really like to see what happens if one of you serious track guys plumbed an oil pressure gauge to the rear of the heads off the oil gallery that feeds the cam bearings or the turbo. Those are the most distant points from the oil pump and should show oil pressure loss first. I would bet that if you did that and plunked the gauge on the top of the dash board staring you in the face you would very quickly figure out what combination of conditions is causing those oil pressure dips.

That is the first thing you guys need to do --- define the problem then you can work on solutions. You can throw money at the problem and install dry sumps, deep oil pans, oil coolers and accusumps but if that solves the problem you still will not know precisely what you fixed. You may only be moving the problem up to a higher rpm or more severe conditions.

Given the amount of money some of you guys are putting in engines, it would be a good investment for 2 -3 of you to put together a logging setup to log oil pressure vs engine rpm and engine load and figure out the exact conditions that are leading to oil system pressure fluctuations. The problem is that the damage is done days or weeks before the engine finally lets go in many instances, with lots of minor injuries from momentary pressure loss adding up to total failure sometimes in a common every day situation like accelerating up an on ramp to merge on a highway. It is very difficult to trace that sort of failure back to its primary cause that might have happened on a track day 3 months prior.

I know some of you are hard core geeks and would have no problem setting up the logging setup, sync it with a in car video and then you know.

Personal example from my youth. Time late 1960's, location on the highway running behind a friend in his 1967 Ford Mustang. Speed about +30 over the limit of 70 mph. I noticed that every time he topped a rise the car would blow out a puff of smoke. What was happening is he was hanging the engine at high rpm continuously for 20 -30 min. The valve covers were getting full of oil as it was getting pumped in faster than it could drain back into the block. Every time he topped a rise that slight negative G as he crested the hill, lifted what oil was still in the pan up into the crank and the oil in the heads backed up even more into the breathers and poof a couple tablespoons of oil exited the engine. Add that up over 20-30 min high speed run, and you loose a lot of oil. I'm not sure why he did not blow that engine that day but the engine compartment looked like an explosion in an oil refinery when we stopped.

It is probably a combination of 5-6 different factors all happening at the same time to make you guys kill the bearings. The better you understand the total picture the easier it will be to come up with a real fix instead of a group of expensive bandaids to solve the problem.

FWIW
Larry

My father and I were talking about mounting it on the head gallery. I have a question though. The pressure should be less at the rear of the head due to pressure drop through the oil galleries to the head, but wouldn't it be more accurate/beneficial to measure the oil pressure at the main gallery (specifically the main gallery that feeds number 3 main)? The pressure should be slightly higher here than at the back of the heads, and measurement should be closer to what the main bearings/rod bearings are seeing. Correct me if I am wrong. I hope my gauge that I will be using is accurate enough to take good measurements. I could borrow a pressure transducer at work to check it.

Jonathon

Larry, how old are you?!!
:p
I'm game and still trying to get one of my EE buddies to get the logging system done for me...mulitple sensors in the motor all with there own channel...kinda of make a time line of the air pocket in the system ;)
maybe gauges and a camcorder will be easier.

Larry, how old are you?!!

I'm a Vietnam era veteran if that gives you a clue --- late 50's.

but wouldn't it be more accurate/beneficial to measure the oil pressure at the main gallery (specifically the main gallery that feeds number 3 main)?
It would be good to log all the engine galleries, but the most distant point should show the worst case (earliest signs of system oil pressure drop). yes in a perfect world you would log oil pressure in each of the main caps supply gallery to see if flow limitations in the combined gallery does not keep up with the oil getting thrown out of those two mains/rods.

Larry

This is an interesting thread.

Not sure if it was clearly explained somewhere in this thread or not....cross-drilling means drilling a second passage in the main journals at 90 degrees to the existing passage (as in a "cross" shape). The reasoning behind this has to do with the main bearings and how the oil is being supplied to the rod journals. The main bearings for the 3 journals that supply the rods are grooved. It is the reservoir of oil created in these grooves that feeds the rods. However, if you look at the bearings you will see that the grooves are not machined the full circumference but instead at the parting line of the bearings the groove has tapered off to nothing. Therefore with a single through-drilled oil passage in the crank, when that passage is in line with the parting line of the bearing the oil flow to the rod bearings is cut off momentarily. By drilling another through-hole at 90 degrees it ensures there is a constant flow between the main journal and rod journal a full 360 degrees of rotation.

With regards to aftermarket billet cranks...many of them are line drilled tying the main journal oil passages together and therefore the rods are fed by multiple mains. Thus by drilling the mains at different orientations relative to each other the same effect is produced.

The same effect as cross drilling can be achieved by machining a full groove on the main bearings...but this reduces the surface area of the bearings and therefore reduces their load carrying capabilities slightly.

This modification is most beneficial at high rpms where oil flow is marginal at best to begin with. Additionally, the inertial loads on the rods increase exponentially with rpm and these loads have a tendency of distorting the big-end of the rod and disrupting the oil clearances. So rod quality and strength are critical for high rpm use so rod distortion is kept to a minimum.

With regards to the oil pump...all Impreza turbo models use essentially the same pump. The Spec C does not have a special pump. However, the 2.0L turbo Legacy models do show a different part number (ending in 270 as mentioned somewhere) and the pump rotor part number is different as well so its possible this pump has increased volume. I will have to order one and check the dimensions. Additionally, Cosworth is now offering a high output oil pump with similar dimensions to the JUN one but at maybe 50% of the price. According to JUN the increase in volume is 20% so I would figure something similar for COsworth.

One of the issues with the Subaru's horizontally opposed design is that oil tends to accumulate in the heads due to lateral g forces in long high speed corners. With the AVCS there is additional oil being dumped into the valve cover when the oil control solenoid is exhausting oil from the cam sprocket during changes in cam position. One thing you will notice with the engines equipped with AVCS is the second set of breather hoses that T together and feed the top of the block....I believe the purpose of this is to help redirect liquid oil back to the block (although I have yet to find any definitive info on this).

Finally....quite often we find that the cause of engine failures is tuning-related and not due to defficiencies in the engine internals. Excessive piston temps (due to either excessive combustion temps or poor ring contact) leading to piston siezure or detonation forces causing a disruption in the oil film. Excessive oil consumption, aside from potentially dropping the oil level also affects the combustion and can cause detonation in an otherwise properly tuned engine. Lots of things to consider and so many variables to balance out to achieve reliability at extreme power outputs.

For anyone seeking JDM Subaru or STi parts, Cosworth, JUN, or other stuff we do supply these parts and do in fact build a lot of custom engines for clients.

--Dave
www.rallispec.com

Good post Dave.

Additionally, Cosworth is now offering a high output oil pump with similar dimensions to the JUN one but at maybe 50% of the price. According to JUN the increase in volume is 20% so I would figure something similar for COsworth.
--Dave
www.rallispec.com

Dave, the -270 PN was probably a 12mm pump. the stock sti has a 10mm rotor pump

cosworth, jun, and cobb all offer a "high volume" 20% increase oil pump.

it's a glorified factory subaru, dual avcs, 12mm oil pump. that being said, I know cosworth does some internal "massaging" to their 10mm pump, and I'm sure the same drilling is done to their 12mm "high volume" pump.

An interesting read.

I keep coming back to the fact that the engineers at subaru are no dummies.
They have kept the cross drilled design for quite a few years now, even after the redesign of the positioning of the thrust bearing they kept the cross drilling.
If the cross drilled design is inherently flawed would they not have changed it?
Surely they would have got excellent feedback from world rally?

I was a firm beleiver that the cross drilling design was the cause of the journal failures but now I am not so sure.
He dont have enough of the altered oiling design cranks out there to get a fair amount of feedback if the bearings are fairing better. So we cant judge on those.
If the cross drilling was at fault why do we see some engines destroying bearings and not others?
Maybe the real culprit here is oil starvation at the oil pickup, throw in the variables of cornering, inconsistent oil levels between engines, quality of tune and irregular high rpm use and it may account for the failures.

We really lack calculated information on how much force is being generated against oil flow due to centrifugal force acting upon the oil. Wouls be good if someone could work this out.......

Unless I am mistaken other manufacturers such as nissan, toyota etc also use cross drilled cranks and are spinning them well over 8000rpm and have no oiling issues. Why are subaru's failing?

I like dave's explanation :)

Turbos defy four stroke, there is no time association. Squirts of timed oil aren't enough- the milliseconds an engine tries turbine mode (hellacious tune ) they are dying until THEY DIE. Very simple. Crossthreading, and more volume was a must do for someone who took the engine that far. I personally would have higher volume on all ej engines, but that is my area going from -20s F to 100F, and very extreme changes inbetween. In fact all engines have proven sime kind of problem going through my area for just one season, that will not be found in a more ambient place. The oil delivery has everything to do with it. The greatest ever encountered personally was the three main bearing subes with a trochoid oil pump- (just keep it full). The ej, just by sight of oem is repulsive to think it is feeding more than ever on that tiny pump. Just my two cents and years of my own mechanical trials. I was hoping to read an upgrade by subaru themselves, but it hasn't happened , unless you find the odd part# doing more as in daves thread states. The miles on the engine with no faults should easily figure that out.

very valid point...have the reason why for my original build I wanted to use an factory crank and see on the dyno at what point the bearings got starved...no g's and no questionable oil level. Then of course a full motor tear down to do some investigation.

As for the WRC statement, their oiling system and I'm willing to bet, crank, isn't remotely close to factory.

Now I do believe starvatoin and bad tuning to have been the cause of a lot of the bearing failures. I also believe that the flawed oil delivery and the repeating same bearings failing point to a root problem.

well, have some pretty cool news to share with the community...
Just got in a new EJ20 crank from the dealership. I opened the box and unwrapped it to start checking it over when I noticed something great about the main journals. They are drilled just like the spec c crank.
I took some pics and have the part number. I'll post it up later on tonight when I get home.
Wonder if this is subaru's solution to sooo many failed rod bearings. Wonder if the new EJ25 cranks are coming the same way...?
have a good one,
Micah

well, have some pretty cool news to share with the community...
Just got in a new EJ20 crank from the dealership. I opened the box and unwrapped it to start checking it over when I noticed something great about the main journals. They are drilled just like the spec c crank.
I took some pics and have the part number. I'll post it up later on tonight when I get home.
Wonder if this is subaru's solution to sooo many failed rod bearings. Wonder if the new EJ25 cranks are coming the same way...?
have a good one,
Micah

Wow! thanks for the info Micah!

Only the main have now 4x holes (90 degrees apart) or does the rod journals also have 4?

It's a wrx EJ205 crank?

yup..four holes=two drillings approx 90* apart....looked as though they might be a bit tighter than 90* apart...but close enough ;)

yeah, EJ205 crank. I have the part number on my phone and will post the pics and number when I have time. Should be later today.

Didn't get to do it last night. Was troubleshooting AEM ignition pick up problems...:(

Bump for the pictures Micah :D

Just wondering now if I should double cross drill the rod journal also like the STI spec C crank :confused: I will be using the 12mm oil pump.

what about the ROD journals? How are those drilled?

rod journals are the same...the main journals are now double cross drilled.

now having issues with we-todd-did-racing...time for the next server :lol:

edit and then my internet took a dump. I'll post them up later today.

Ok. Thanks for the info.

ok here we go...the shiny crank is obviously the new one with part number on the box...the old crank pics are just for reference.

http://i108.photobucket.com/albums/n22/drummerboy1784/SSPX0485.jpg
http://i108.photobucket.com/albums/n22/drummerboy1784/SSPX0486.jpg
http://i108.photobucket.com/albums/n22/drummerboy1784/SSPX0487.jpg
http://i108.photobucket.com/albums/n22/drummerboy1784/SSPX0488.jpg
http://i108.photobucket.com/albums/n22/drummerboy1784/SSPX0489.jpg

-Micah
p.s. sorry pics were taken on my phone

Thanks for the pics.

I have several subie short blocks to study. I have only taken a few apart. I have a 2.2 na motor that has 360 degree grooves in all the main shells. I have a 2.5 na that only has the thrust main with 360 degree groove. I haven't taken a sti short block apart yet to see. I also have a 2.0 closed deck sb that I will be taking apart. On the statement about running more clearances thats not for me. That would require more volume and thicker oil that doesn't flow as well. That approach is for drag motors IMO. Any comments will be welcome.

This is an update, on all the subies I have taken apart the block has a 360 degree groove running under the main shells so oil is ALWAYS supplied through the holes in the main shells no matter where the crank is. Maybe the main shells oil holes could be elongated in their grooves to provide more volume. I think I will cross drill my cranks anyway but the deal about the grooves in the main shells stopping at the center or part line is not why the cranks were crossdrilled. I would like to see a new set of bearings that goes with the new crank to see if the're any different.

Charlie

The USDM EJ257/255 has the thrust/center/front (1-3-5) bearings with the 360 grooves in the bearings...the other ones, 2 and 4, do not have grooves.

The USDM EJ257/255 has the thrust/center/front (1-3-5) bearings with the 360 grooves in the bearings...the other ones, 2 and 4, do not have grooves.

Thats very interesting information.
I was doing some research on crank oiling. It seems many high revving engines use the cross drilled design for example the honda S2000 and aftermarket cranks such as TODA for nissan/honda's. If the cross drill design was so inherently flawed I would expect TODA and JUN would not be using this method.

I checked out the ACL bearings website. You can call up bearings for various engines and it shows a detailed drawing of the bearing shells. Its interesting to note that the Subaru design is not really used in other engines.
On many other engines the load bearing area of the bearing has no groove and the groove only appears to the sides of the shells where the load is reduced. Its odd that the Subaru bearings are the opposite, even after taking into consideration the boxer layout it doesnt make sense.
Subaru's use of a full grooved bearing shell is much more logical, this was not always the case.

In my opinion if you have the 4 oil hole hole type crank and full groove bearings you should be ok in that area.
That just leaves-
1- Uninterrupted oil supply to the oil pump (oil pan level)
2- Non aerated oil being sucked up by the pump
3- Adequate oil pressure/volume (maybe the 12mm pump will sort this out)
and finally.....
4- Bearing clearances.

You have to keep in mind you are talking about a "system" you can't judge the merit of a feature in isolation. Cross drilled cranks are, very cheap and easy to build, and very good for reliablity for low stressed engines below their rpm cutoff. That rpm cutoff is determined by, journal diameter, engine rpm, oil pump supply pressure and volume, bearing clearances, and journal/bearing width and bearing loading. Just because a 237 hp S2000 turns 9000 rpm on a cross drilled crank, does not prove that a cross drilled crank in a 500 hp turbocharged engine that has over 2x the bearing loading, is a suitable combination.

Assuming the info I found on the net is correct, the main bearing journal on the S2000 is .784 inches wide, vs our 0.6875 wide mains (14% more bearing area). I believe the journal diameters are similar diameter so they are carrying 1/2 the load on larger bearings when compared to a modified Subaru.

As a system there are a dozen ways to solve the problem, go to wider bearings (not likely needs to redesign the whole engine), up the oil pressure and volume flow, or change bearing clearences so you have a thicker oil film, or change the crank drilling design so it is more favorable to the higher bearing loadings seen in a high performance turbocharged engine.

The cross drilled design is not "defective" it is simply is not ideal/suitable for this application in my view.

Change any one of those key secondary factors like bearing loading and you change the whole equation regarding how successful the cross drilled design is for a given situation.

Larry

The cross drilled design is not "defective" it is simply is not ideal/suitable for this application in my view.


Subaru are now supplying cross drilled (main journals) cranks for wrx's with 227HP to the engine 7K rpm, like Homemade WRX told us. The spec C also uses cross drilled cranks (main and rod journals). All of this with the 10mm oil pump, so I'm stating to think we're on the right track to solve our oiling issue. It's a good and inexpensive mod to do on our build engines, adding the 12mm oil pump is not a bad idea also.

EDIT: nope I was wrong, the spec c doesn't have the rod journals cross drilled, my bad.

The USDM EJ257/255 has the thrust/center/front (1-3-5) bearings with the 360 grooves in the bearings...the other ones, 2 and 4, do not have grooves.


1-3-5 are exactly where Subaru are now cross drilling their cranks, they are the main journals that feeds the rods.

Now, why don't they cross drill the rod journals also? we know that the spec C cranks are. The diff between the wrx and spec C --> about ~100HP and 1K rpm.

EDIT: nope I was wrong, the spec c doesn't have the rod journals cross drilled, my bad.

Now, why don't they cross drill the rod journals also? we know that the spec C cranks are.
are they?...I thought it was only the mains...time to find some pics again.

Post #126 ;)

EDIT: nope I was wrong, the spec c doesn't have the rod journals cross drilled, my bad.

Ok so everybody thinks that because straight 4s spin 8 or 9k a subie needs to? yeah it would be really nice and I would like to hear mine singing the song like everyone else. But whats wrong with making all the hp and lots of torque at 7500 and being happy with that. I live close to a highway and when I'm out in the shop I sometimes hear a crotchrocket singing the song and have to pause to see how long he stays in it. I've heard it so much on honda bikes that it still gives me chills. Even my sportster at 7500 is kinda neat. Needless to say a sportster won't live very long at 7500. I spent 4k trying to make it outrun hondas. My son traded a Integra GSR for the STI and he also misses the higher rpms. But I don't like to deal with spun bearings either so a revlimiter will have to limit it slightly. If you have the power you won't be wasting time shifting, if the power will support taller gears. And maybe till we find a better solution to cross drilling, 360 degree main shells, 12mm pumps, better cams and springs and a big turbo we might get reliability at 8k.

Charlie

I agree with you there charlie but when 8k isn't enough or doesn't reach your goals what then?...you have to flow more air to make more power or desire a taller powerband to take advantage of shorter gearing. When that comes, well, you then have a thread like this and that's why we are having it...sorry but a 2.5 at 8.5k isn't going to cut it for me. A 2.7 at 8k won't either...
just my $0.02,
Micah
p.s. I think most in this thread are trying to do just a little more than the normal rotated set up on an sti...for some 500 whp just isn't enough ;)

1-3-5 are exactly where Subaru are now cross drilling their cranks, they are the main journals that feeds the rods.



Just to avoid some confusion and misuse of terminology --
The stock 2002 WRX had a fully cross drilled crank! (post #43 page 2 has a picture of the OEM wrx crank from the 2 liter engine)

Cross drilling a crank refers to there being a single hole that passes all the way across the main journal forming 2 openings 180 degrees apart both feeding a galley drilled from the rod which intersects at the center of that cross drill. The term has been in use since the 1950's for that design. The "newer" cranks are now cross drilled with 2 passages. The term cross drilling has nothing to do with the X pattern formed by the two holes.

These are simply double drilled cranks. The design still has the limitation of being forced to fight centrifugal force to get the oil into the center of the journal before it can get to the rod. By providing 4 passage openings to the main bearing it will also increase oil loss from the main bearing so oil pump volume flow will need to be higher to maintain the same oil pressure in all likelyhood.

There are specially designed crank drillings that do not pass all the way through the crank journal and do not force the oil to go all the way to the center of the main journal to get to the oil feed galley to the rod bearing. The drill the passage from the rod to the main at a diagonal that breaks out of the main journal at its surface or very near it to another highly angled drill passage coming in from the main. This sort of drilling is used in many domestic V-8 engines to allow them to live at high rpms. In the journal sizes common for domestic V-8's the cross drilled pattern begins to fail at about 8,000 rpm give or take a bit.

Larry

These are simply double drilled cranks. The design still has the limitation of being forced to fight centrifugal force to get the oil into the center of the journal before it can get to the rod. By providing 4 passage openings to the main bearing it will also increase oil loss from the main bearing so oil pump volume flow will need to be higher to maintain the same oil pressure in all likelyhood.

I agree with you on both counts but a "straigh shot" oiled crank still has the same issue with centrifugal force but just with the mass of one have volume of the cross drilling or 1/4 that of the double cross drilled crank.

I really wish one of my local machine shops had a guy worth a poop running their 6-axis cnc lathe... :(

This is a Ferrari V-12 crankshaft and has the same sort of high angle drilling used in American V-8's to keep them alive at high rpm.

(source http://www.rpmvt.com/2007/06/drilling-crankshafts.html)
http://www.rpmvt.com/uploaded_images/IMG_2807-714988.JPG

And for those of you who missed it in earlier discussions on crank drilling heres is the account by Rehr Morrision why the cross drill design should be avoided in high rpm engines. (Rehr Morrison is one of the premier racing engine builders in the U.S.)
http://www.rehermorrison.com/techTalk/51.htm

How many of you thoroughly clean the crank shaft oil galleys after you kill an engine before you rebuild it ?

Larry

This is a Ferrari V-12 crankshaft and has the same sort of high angle drilling used in American V-8's to keep them alive at high rpm.

(source http://www.rpmvt.com/2007/06/drilling-crankshafts.html)
http://www.rpmvt.com/uploaded_images/IMG_2807-714988.JPG

And for those of you who missed it in earlier discussions on crank drilling heres is the account by Rehr Morrision why the cross drill design should be avoided in high rpm engines. (Rehr Morrison is one of the premier racing engine builders in the U.S.)
http://www.rehermorrison.com/techTalk/51.htm

How many of you thoroughly clean the crank shaft oil galleys after you kill an engine before you rebuild it ?

Larry

it's interesting, it looks like the 2nd main is double drilled?

http://www.rpmvt.com/uploaded_images/IMG_1920-742592.JPG

I really appreciate the thorough explanation of the drillings in the crank. In my case I was aware of the terminology but got lazy in my expression of crossdrilling. Since the factory crank is already cross drilled I meant adding another 90 degree drilling to the crank. The ferrari stuff is neat. Boy, look how wide the mains are. Don't the wrc guys spin more than 8k? I wish someone would share their expertise on these motors. Also while I was studing thrust bearings I got to thinking about the oil holes in the grooves in the shell. It looks like those holes could be elongated to add more volume to go with the additional drilling of the crank. Maybe even deepen the groove in the block. That and adequate pressure to go with the 12mm volume seems to me would help. Also I wonder how much excessive end play reduces the volume to 2 and 3 rods on phase 1 motors, but in that regard P2 motors don't have the sides at all. Also since the thrust has been moved to #5 how does this effect the oil control at #3 main to supply #2 and #3 rods. I like the idea of the thrust at #3 main to keep the oil pushed out to the rods, what I don't like is the smaller thrust surface area of the center thrust bearing. These big pressure pressure plates are probably killing the thrust bearings. In that regard the thrust needs to be at #5. I wonder why we can't use two thrust bearings, maybe allowing for the different expansion rates of the crank and block. Maybe after adding a rear thrust to a P1, giving the center thrust more clearance so it's just trying to hold the oil in? Also is this style of pump good at any rpm and is the pickup large enough for the volume at the rpms your trying to achieve? Larry, and Homemade, and any one else, would you please comment? Once it gets cooler outside I won't bother you guys so much.

Charlie

WRC engines do not run high RPMs....they run a restrictor plate that effectively makes their powerband exist in the 2400~5500 rpm ranges.

Also is this style of pump good at any rpm and is the pickup large enough for the volume at the rpms your trying to achieve?
Charlie

let me ask you charlie, are you worried about pumping too much oil into the heads, with the larger pump? Thus, starving the motor for oil, destroying your rod bearings, and starting this all over?

plain and simple... what will it take for a 9500rpm redline safely ???

plain and simple... what will it take for a 9500rpm redline safely ???

a honda s2000 :lol:

safely? a good 20k.

custom block
custom crank
custom bearings
custom oil pump
custom rods (prolly titanium)
custom pistons for your rods

lots of pain and custom suffering. :lol:

plain and simple... what will it take for a 9500rpm redline safely ???

I think that's what we are trying to find ;)
I'm first using a factory crank and then a billet crank...then I'll be going to a drysump set up.

Charlie, I have commented on here before about running double thrust bearing setups to guys running EJ22t's as they are going to have the machining for it anyhow.
I'd personally like to test it if I run into issues running a heavy push style triple plate.

plain and simple... what will it take for a 9500rpm redline safely ???

just to reiterate what I said earlier:

Homemade WRX
Scooby Guru

Member#: 33782
Join Date: Mar 2003
Chapter/Region: MAIC
Location: Virginia Beach, VA
Vehicle:
94 WR-L
custom parts cost lot o/$





:lol:

charliew and I will be using larger oil sumps to help with any such oil starvation problem when using a larger oil pump. Most likely we will not be doing a considerable amount of autoxing so the extended high rpm runs will be kept at a minimum. We may be doing some drag racing however, but the oil starvation problem will be less likely on straight, 1/4 mile runs.

just to reiterate what I said earlier:

Homemade WRX
Scooby Guru

Member#: 33782
Join Date: Mar 2003
Chapter/Region: MAIC
Location: Virginia Beach, VA
Vehicle:
94 WR-L
custom parts cost lot o/$





:lol:

ROFL...yeah but those aren't the expensive parts...my custom rods, pistons, crank and 6-spd dogbox are...

the rest of the build doesn't seem to hurt nearly as much ;)

oh yeah, 14mm headstuds aren't too cheap either

it's interesting, it looks like the 2nd main is double drilled?
I had noticed that too but it looks like they come out at one point on the other side...can't quite make it out.

I didn't remember the deal about restricter plates on the wrc cars, I guess that saved the guys a bunch of money. I'm not at all worried about pumping too much oil to the heads, as wittmer25 said earlier. My subie has a larger capacity oil pan that I don't think I can run at high rpm long enough to empty. It's got a Kennedy oil pan kit with gates from a Speedway Motors sbc claimer kit. It's short and wide. I'm just mainly building a street motor. One is for a 914 and the other is a manx style dune buggy. I've been on the buggy awhile and have decided the 914 will be simpler to finish so have started accumilating parts in that direction.

When the guys run on a track with stock pans why couldn't they just run an extra quart of oil? When I was making my pan I poured water in it to check for leaks. when the dipstick says full the oil is quite a ways down in the pan. Try it on a stock pan and check to where the extra quart comes to. don't forget the filter holds about a cup or two. Push the dip stick tube in the pan and put the dip stick in and check it out. All of the people that do vw subie conversions use short pans that have about 1&1/2 to 2 inches cut off and they run the same amount of oil, they say without problems. It's just an idea. Sorry for getting off subject a little.

Charlie

And for those of you who missed it in earlier discussions on crank drilling heres is the account by Rehr Morrision why the cross drill design should be avoided in high rpm engines. (Rehr Morrison is one of the premier racing engine builders in the U.S.)
http://www.rehermorrison.com/techTalk/51.htm

very interesting.

seems to me that you can effectively eliminate a cross drilled gallery by welding up one side.

it won't be as good as a purpose-drilled "high speed" gallery, but it's a step in the right direction.

ken

seems to me that you can effectively eliminate a cross drilled gallery by welding up one side.

it won't be as good as a purpose-drilled "high speed" gallery, but it's a step in the right direction.


I think it was the old MG's (it is here some where but I can't find it right now) pressed a brass plug in one end of a cross drilled crank. If the plug came out, oil pressure dropped 5 psi.

Larry

its too bad that cobb or axis don't offer a decent block built for high revs....

or do they??

I didn't remember the deal about restricter plates on the wrc cars, I guess that saved the guys a bunch of money.

FAR from it. The thermal loading as well as the basic mechanical stresses are outasight.

That's a good point to keep in mind though... when you see something modified a certain way, it's imporant to think of what problems they have that they're trying to solve. They're not worried about high RPM operation in WRC just the same as Ferrari isn't worried about running extreme boost in a high compression engine with the thermal loads associated with trying to keep a turbo maxed out despite the best efforts of a restrictor...

Just to avoid some confusion and misuse of terminology --
The stock 2002 WRX had a fully cross drilled crank! (post #43 page 2 has a picture of the OEM wrx crank from the 2 liter engine)

Cross drilling a crank refers to there being a single hole that passes all the way across the main journal forming 2 openings 180 degrees apart both feeding a galley drilled from the rod which intersects at the center of that cross drill. The term has been in use since the 1950's for that design. The "newer" cranks are now cross drilled with 2 passages. The term cross drilling has nothing to do with the X pattern formed by the two holes.

These are simply double drilled cranks. The design still has the limitation of being forced to fight centrifugal force to get the oil into the center of the journal before it can get to the rod. By providing 4 passage openings to the main bearing it will also increase oil loss from the main bearing so oil pump volume flow will need to be higher to maintain the same oil pressure in all likelyhood.

There are specially designed crank drillings that do not pass all the way through the crank journal and do not force the oil to go all the way to the center of the main journal to get to the oil feed galley to the rod bearing. The drill the passage from the rod to the main at a diagonal that breaks out of the main journal at its surface or very near it to another highly angled drill passage coming in from the main. This sort of drilling is used in many domestic V-8 engines to allow them to live at high rpms. In the journal sizes common for domestic V-8's the cross drilled pattern begins to fail at about 8,000 rpm give or take a bit.

Larry

Hotrod, I don't know where you come up with this knowledge, but thank you for explaining the finer details. I am battling this problem as I type this. My crank was drilled per my builder's specs and I suspect that the oil pressure loss is due to this practice. I am in the process of installing the 12mm JDM pump into my system to band-aid the situation. Seems silly to cross drill if Phil Grabow is spinning his motor harder than anyone in this thread, winning time attacks, and using only the stock oil pump and crankshaft :confused:. This is without problems and verified by tearing down the motor after part of the race season.

Thanks Hotrod
CP

Anyone have any "straws" they can push through the Spec C's crank?
I would want to drill my 2.0L/2.2L cranks to be the same if possible.

Anyone have any "straws" they can push through the Spec C's crank?
I would want to drill my 2.0L/2.2L cranks to be the same if possible.

I posted these pictures several years ago:


Here is a shot of a Version 7 RA Spec C crank:

http://www.sponaugle.com/nasioc/SpecC-crank1.jpg

http://www.sponaugle.com/nasioc/SpecC-crank3.jpg

As you can see, this factory crank (rated to 8300 rpm from Subaru) uses the dual drilled oil feeds on all three case surfaces.



The Spec C crank simply has a second set of thru-drilled holes, 90 degrees from the first set.

Jeff

Apparently it works. *shrug*

X2

:confused:

The Spec C crank simply has a second set of thru-drilled holes, 90 degrees from the first set.

Jeff
yes, but they are 45* off from standard oil delivery holes...I need to look further at the standard and "spec c" crank I have...now that I'm wondering why they shifted it 45*

yes, but they are 45* off from standard oil delivery holes...I need to look further at the standard and "spec c" crank I have...now that I'm wondering why they shifted it 45*

Interesting.. I never noticed. I'll pull out a WRX and a Spec C and compare and take a few pictures.. Once I get done playing around on the dyno with my GTO... man o man 6.0Ls at 10psi makes some fast torque. I can hit 370 lb-ft at 2000 rpm. Me likey displacement. ;)

Cheers,

Jeff Sponaugle

I took pics of them next to eachother...one thing I forgot is that Nick is angry at dominic...so you have to put in get-a-dom-tune where google is...but take away the -'s
;)

I'll just post them in this thread a little later.

oh and I'm enjoying my new 7.3L at about 30 psi :D

enjoy http://i108.photobucket.com/albums/n22/drummerboy1784/SSPX0486.jpg
new crank 3
http://i108.photobucket.com/albums/n22/drummerboy1784/SSPX0487.jpg
old crank 1
http://i108.photobucket.com/albums/n22/drummerboy1784/SSPX0488.jpg
old crank 2
http://i108.photobucket.com/albums/n22/drummerboy1784/SSPX0489.jpg

Homemade WRX,

I'm a bit confused how the holes connect. Can you put straws through your new ej205 crank so i can see this, or maybe explain it.

Thanks

yeah, let me grab one and toss some straws through for visual. I'll post it up tomorrow.

wheres the best place to get your crank drilled?

How much higher should I be able to keep oil preasure and flow up ???

yeah, let me grab one and toss some straws through for visual. I'll post it up tomorrow.

forgot the only one that I have right now is being cryo'd right now...so "straw" pics will have to wait a little longer

Great thread guys, Am new to subaru engine building so don't shoot me.
I currently have a GTR skyline and have had a look at the oiling system on it that may help.
These engines have a 8250 rev limit stock and will gladly rev higher with few oiling issues.
First things are oil pickup starvation on heavy corners due to gforces(fixed by baffles around pickup
Second is over oiling to the cams(fixed by restricting oiling to the top end) cams only need minimal oiling due to slow revs and no heavy loading as associated with mains or rods.
Third is faulty oil pump drive(fixed by using a longer pump drive on the crank)
And finally drain back from the head(fixed by plumbing a -10 line from the back of the head to the sump
Now some of you are saying cross drill and some are saying don't and some of you say that it is because the oil hole is at 90deg.
The RB26 in gtr's run there oil holes at 90deg aswell and run 10psi of oil pressure per 1000revs but difference is they run full groove mains on top and bottom main bearings and numerous holes on the rod bearing bottom shell.
My engine in particular makes over 800hp at the wheels running 10,000 revs 30psi boost and 100psi oil press at max revs with no cross drilling or oil chamfers on the crank, I run .002" on the mains and .0025" on the rods.
Running larger than .002" to .0025" on the mains in a subaru engine seems a little big to me as taking into account the expansion rate of the cases you will end up with more like .003 to .0035" which in turn will lose oil pressure and also cause the crank to whip slightly
There are quite a few GTR engines that rev to 13,000 and 45psi boost with aftermarket cranks that seem to only cross drill keeping them at 90deg to the crank.
I am just a bit puzzled as to why you are so worried about centrifigal force when these engines run similar crank designs.
I think your issues are more in the feeding as stated by someone else how it feeds 2 rods of one main and also the oil hole phasing.
As for phasing there is more load on the crank about 15 to 20deg ATDC as the combustion process is in full swing as opposed to BTDC when there is still pressure applied but nowhere near as much, Having said this you need to pre empt this and time them a little earlier so as it has full oil pressure at this point
As for loosing HP with higher oil pressure, i would rather loose 7 to 10hp in knowing that my bearings are not going to run dry with the higher oil pressure, and taking into account that there are a number of 90deg turns in which you usually loose some pressure in the engine it is wise to test oil pressure at a number of locations with the last point of oiling usually the worst.
Don't mean to step on anyones toes, they are just some of my theories

Great thread guys, Am new to subaru engine building so don't shoot me.
I currently have a GTR skyline and have had a look at the oiling system on it that may help.
These engines have a 8250 rev limit stock and will gladly rev higher with few oiling issues.
First things are oil pickup starvation on heavy corners due to gforces(fixed by baffles around pickup
Second is over oiling to the cams(fixed by restricting oiling to the top end) cams only need minimal oiling due to slow revs and no heavy loading as associated with mains or rods.
Third is faulty oil pump drive(fixed by using a longer pump drive on the crank)
And finally drain back from the head(fixed by plumbing a -10 line from the back of the head to the sump
Now some of you are saying cross drill and some are saying don't and some of you say that it is because the oil hole is at 90deg.
The RB26 in gtr's run there oil holes at 90deg aswell and run 10psi of oil pressure per 1000revs but difference is they run full groove mains on top and bottom main bearings and numerous holes on the rod bearing bottom shell.
My engine in particular makes over 800hp at the wheels running 10,000 revs 30psi boost and 100psi oil press at max revs with no cross drilling or oil chamfers on the crank, I run .002" on the mains and .0025" on the rods.
Running larger than .002" to .0025" on the mains in a subaru engine seems a little big to me as taking into account the expansion rate of the cases you will end up with more like .003 to .0035" which in turn will lose oil pressure and also cause the crank to whip slightly
There are quite a few GTR engines that rev to 13,000 and 45psi boost with aftermarket cranks that seem to only cross drill keeping them at 90deg to the crank.
I am just a bit puzzled as to why you are so worried about centrifigal force when these engines run similar crank designs.
I think your issues are more in the feeding as stated by someone else how it feeds 2 rods of one main and also the oil hole phasing.
As for phasing there is more load on the crank about 15 to 20deg ATDC as the combustion process is in full swing as opposed to BTDC when there is still pressure applied but nowhere near as much, Having said this you need to pre empt this and time them a little earlier so as it has full oil pressure at this point
As for loosing HP with higher oil pressure, i would rather loose 7 to 10hp in knowing that my bearings are not going to run dry with the higher oil pressure, and taking into account that there are a number of 90deg turns in which you usually loose some pressure in the engine it is wise to test oil pressure at a number of locations with the last point of oiling usually the worst.
Don't mean to step on anyones toes, they are just some of my theories


seems like those nissan engineers know thier stuff... 1300 RPM ???:eek:

wow I would KILL to be able to ROAR that high in my RS :devil:

Back in the day, from talking to a few sandrail guys, they were having rod stretch issues in our boxer engines from the "slidehammer" effect on the rod. Above 10k rpm, the rods would stretch and wreak all kinds of havoc. Input like what you've got is always valuable. You're running a straight 6 that's supposedly balanced similar to a boxer, but it treats the thrust forces differently to achieve its balance. They get 15k rpm out of our engines N/A for Japanese racing circuits and make just shy of 600hp in the process, but it takes a beefy bottom end, dry sump oiling, ITB's, and huge ports. They also cost $30k. 8-9k rpm is budgetable for my purposes out of a 2.5L. My n/a engine doesn't need 100psi of oil pressure, but it has to live at higher revs.

Back in the day, from talking to a few sandrail guys, they were having rod stretch issues in our boxer engines from the "slidehammer" effect on the rod. Above 10k rpm, the rods would stretch and wreak all kinds of havoc. Input like what you've got is always valuable. You're running a straight 6 that's supposedly balanced similar to a boxer, but it treats the thrust forces differently to achieve its balance. They get 15k rpm out of our engines N/A for Japanese racing circuits and make just shy of 600hp in the process, but it takes a beefy bottom end, dry sump oiling, ITB's, and huge ports. They also cost $30k. 8-9k rpm is budgetable for my purposes out of a 2.5L. My n/a engine doesn't need 100psi of oil pressure, but it has to live at higher revs.

any link to a high reving NA boxer ??

I was not aware they had taken them that far :eek:

I do need (would like)100psi @ 9500 and will have a dry sump. What worries me is a post in another thread here were a dry sump setup is having trouble making 65psi@ 7000rpm with 20/50 oil.

Hi, I currently run a dry sump setup and have no problems getting 100psi with 10/60 tws motorsport oil, but all i can suggest is that possibly he has not done his maths for the pulley sizes or is running a lot of bends or has not set his pressure relief properly.
I run a four stage with -12 lines for scavenge and inlet to the pump and
-10 lines for outlet to engine with a peterson filter, all lines are kept as straight as possible and as short as possible.I do need (would like)100psi @ 9500 and will have a dry sump. What worries me is a post in another thread here were a dry sump setup is having trouble making 65psi@ 7000rpm with 20/50 oil.

Is this possible? They drill a hole and chamfer it on the rod journal face of cranks for V8's. Does anyone do that for our cranks or has tried it? It improves oiling in that area, supposedly. It's a pretty standard thing on V8's...

^ why do people get banned so damn fast ???

Hi, I currently run a dry sump setup and have no problems getting 100psi with 10/60 tws motorsport oil, but all i can suggest is that possibly he has not done his maths for the pulley sizes or is running a lot of bends or has not set his pressure relief properly.
I run a four stage with -12 lines for scavenge and inlet to the pump and
-10 lines for outlet to engine with a peterson filter, all lines are kept as straight as possible and as short as possible.

someone who understands fluid mechanics and flow losses:banana:


edit:nevermind...saw why the new guy was already banned.

Now some of you are saying cross drill and some are saying don't and some of you say that it is because the oil hole is at 90deg.
The RB26 in gtr's run there oil holes at 90deg aswell and run 10psi of oil pressure per 1000revs but difference is they run full groove mains on top and bottom main bearings and numerous holes on the rod bearing bottom shell.

I am just a bit puzzled as to why you are so worried about centrifigal force when these engines run similar crank designs.
I think your issues are more in the feeding as stated by someone else how it feeds 2 rods of one main and also the oil hole phasing.


I would like to see the rod bearing size differences between the RB26 and an EJ257. Specifically, the diameter and width.

Do you have any pics?

Surface area comes into play as I too have thought about multiple holes in the bearing shell.....instead of the usual 1.

I've already looked into them and have a huge collection of bearing size and widths from when I was hunting down my source for a better bearing size.
The RB25/26 are essentially a 48mm diameter and 17.1mm wide. IIRC the VG30 and RB30 are the same as well.
We are 52mm (except phase 1 EJ25) and 16.5mm wide.

I've already looked into them and have a huge collection of bearing size and widths from when I was hunting down my source for a better bearing size.
The RB25/26 are essentially a 48mm diameter and 17.1mm wide. IIRC the VG30 and RB30 are the same as well.
We are 52mm (except phase 1 EJ25) and 16.5mm wide.

SO our journal speed is faster at the same rpm AND less surface area.

I would like to see the rod bearing size differences between the RB26 and an EJ257. Specifically, the diameter and width.

Do you have any pics?

Surface area comes into play as I too have thought about multiple holes in the bearing shell.....instead of the usual 1.
I will take some pics this week and post em up.
Does any company make a full groove bearing for 2 and 4 or can you modify a shell from 1,3 or 5 to fit.
Haven't taken a close look yyet

we actually have 858mm^2 to their 820.8...but our bearing speed is faster

quick question... When my machine shop built my block, they used slightly oversized beaings ( as the originals where spun)

do you think these slightly oversized bearings will help with lubrication at all ??...

I wonder just how much bigger they went...

SO our journal speed is faster at the same rpm AND less surface area.

this might be an issue...

oversized bearings are such a small change I wouldn't really consider them to have any benefits