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Old 03-08-2006, 02:09 PM   #1
HamFist
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Default Cross-drilling our crankshafts?

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...
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Old 03-08-2006, 02:19 PM   #2
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Is it hollow in there? If someone local wanted to find out, I've got a few crap cranks laying around.
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Old 03-08-2006, 02:27 PM   #3
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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.

S.
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Old 03-08-2006, 03:18 PM   #4
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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.
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Old 03-08-2006, 08:49 PM   #5
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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.
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Old 03-09-2006, 11:01 AM   #6
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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.
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Old 03-09-2006, 11:55 AM   #7
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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.
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Old 03-09-2006, 12:33 PM   #8
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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.
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Old 03-09-2006, 12:46 PM   #9
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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.



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Old 03-09-2006, 12:50 PM   #10
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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).
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Old 03-09-2006, 02:04 PM   #11
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Quote:
Originally Posted by 8Complex
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....
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Old 03-09-2006, 03:02 PM   #12
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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!!
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Old 03-09-2006, 04:46 PM   #13
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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...
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Old 03-09-2006, 10:16 PM   #14
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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.
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Old 03-10-2006, 01:13 AM   #15
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Quote:
Originally Posted by 8Complex
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.
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Old 03-10-2006, 03:18 AM   #16
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all this talk about oil... i wonder if anyone has done a basic 3 stage dry sump system?

*no intention of jacking this thread*
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Old 03-10-2006, 09:02 AM   #17
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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?
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Old 03-10-2006, 11:15 AM   #18
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Quote:
Originally Posted by HamFist
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.
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Old 03-10-2006, 11:28 AM   #19
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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?)
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Old 03-10-2006, 11:42 AM   #20
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Quote:
Originally Posted by Freon
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.
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Old 03-10-2006, 11:59 AM   #21
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Quote:
Originally Posted by jam69007
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.
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Old 03-10-2006, 12:58 PM   #22
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Quote:
Originally Posted by 02Toyowrx
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.
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Old 03-11-2006, 11:23 PM   #23
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Quote:
Originally Posted by Freon
Are oil pumps positive displacement pumps, or near-so?
Yes, they're positive displacement.
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Old 03-12-2006, 09:31 AM   #24
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Quote:
Originally Posted by mick_the_ginge
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
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Old 03-12-2006, 06:17 PM   #25
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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?
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