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Old 01-12-2018, 01:36 PM   #26
Steve240
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Bumping this thread to get opinion's on a line boring question.

New here, relatively new to subaru as well.

Picked up a salvage car for a project, stripped down an EJ25 and took it into the machine shop I have used before for a motor build to have it cleaned and inspected. I am being told that the line bore is out of spec by 0.001" on main 5 closest to the flywheel.

I've spent the last couple days looking into information on this and this thread is about the most helpful thing I've come across.

Do I really need to spend the money on a linebore for 0.001, I am not building a race engine. I get if it was 0,005 out like mentioned above it needs to be fixed. Couldn't I run larger oil clearance ACL bearings and crank would never know journal 5 was 0.001 out? Do I even need to do that?

The machine shop was going to send it to another shop, there head quarters to have a second look at it before doing any work but I would appreciate any response with first hand experience.
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Old 01-13-2018, 04:13 PM   #27
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You could run thicker oil, +1 bearings or another bandaid to get it close to spec but it’s not the best way to go about it. What are the actual main clearances as of now?

Keep in mind you can get new blocks for about 1500$ so when you factor that in, the machine work usually doesn’t make financial sense for a DD.
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Old 01-13-2018, 05:17 PM   #28
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Either run the tighter main bearings or get a new block. I would run the tighter mains.
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Old 01-15-2018, 11:37 PM   #29
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You gotta ask them how it is out of round. 3 to 9 o'clock, or 6 - 12 o'clock.
Heat from rod bearing failure will warp the mains.
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Old 01-18-2018, 10:36 AM   #30
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Unless that machine shop has extensive experience with Subaru's, you are better off taking it elsewhere. The rear main seldom gives a problem, more than likely what they are measuring is a result of 2 possible scenarios. A bent rear dowel or the dowel is just too loose fitting in the driver side case half. You can't just torque the empty halves together and expect them to line up perfectly, because of the loose fit of the dowels.
The proper way is to barely hand tighten the case bolts, measure with a dial bore gage at the parting surface and tap one half in the direction it needs to go to align the halves. At this point, then the mainline can be measured accurately. When the crank and bearings are installed in one half, they pretty much align the second half when it gets mated up.
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Old 10-07-2018, 11:16 AM   #31
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Is there a DIY to check if mains are true or is it a 100% given that if its a used block then it will be out also I have checked high and low but can find only one reference on the internet of our mains diameter being 2.5200'' can anyone else confirm ?
Not even my Subaru manual mentions mains bore diameter.
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Old 10-08-2018, 01:33 PM   #32
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The OE Subaru spec for the main housing bore can vary from different bearing manufacturers. In fact, I think the maximum listed by Subaru is 2.5197" yet most of King's main bearing listings show 2.520" as a minimum. It's best to use the size listed from whatever bearing brand you're using because it affects the crush.
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Old 10-13-2018, 12:13 AM   #33
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Bumping thread.

I have just recieved my block back from having a line hone performed with ARP case bolts. (No Line bore) Aparently 0.002 was taken off the parting face. Then assembled, torqued with ARP bolts and honed. The 3 inner main parting faces have also been CNC dowelled/pinned with 6mm dowels.

I have just began to split the case and clean and do some main bearing measuremnts etc. And I noticed the #5 main case bolts were not torqued up. All the other bolts were tight to undo.

I have inspected the washers of the bolts, and it is clear the bolts were not torqued because there is no wear on the washer surfaces. All the other bolts have suffing on the washers as you would expect after torquing them. Yes, the ARP fastener lube was used, but even still, there is very minor galling/wear when they are torqued.

I also inpected the aluninium surface of the case that the bolt heads/washers seat against. The #1 mains (and all the middle mains in the water jacket) have fresh wear on the mating surface. The #5 mains on the other hand only have old wear (because used case) this is evident by the colour of the aluminium where the bolts meet. The torqued bolts have a fresh and more aggressive wear pattern, the non torqued bolts have an old aged dull looking wear pattern. Been over a year since the case has been apart, so aluminium has had time to age/oxidize the surface. Also, because OEM bolts arent as tight, then i suspect the aluminium galls/wears less with OEM bolts, which reflects my observations.

The primary reason I had the line hone performed was to take advantage of the ARP case bolts additional clamping. These are known to distort the tunnel when fully torqued, hence requiring a line hone and/or bore in order to use them. There are numerous reports of the cases distorting so much with the ARP bolts that the crank wont even turn when assembled without the line hone procedure.

Will having them re-do the work be ok. This particular shop has a good reputation in my area. And very few other shops have such a good reputation. So I would not even know where else to take it.

I have photos of all the bolt surfaces, both before and after cleaning.

I am now going to carry on splitting the case, cleaning and re-assembling and doing some measurements.
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Old 10-13-2018, 10:31 AM   #34
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If you have the tools, I'd torque and measure the mains and see if you even have an issue.

If you have an issue, I'd call and tell the shop what you found about #5 bolts being loose while the others were torqued.

Yes, they can remachine it. If I were doing the op, I'd blue the main journals to make sure there wasn't a distortion from #5 being loose before and tight now. Might get a cattywampus cut on the others but it'll probably be ok.
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Old 10-13-2018, 10:53 AM   #35
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Yes. I have measured the mains, and #5 (once I properly re-torqued) is over 0.001 smaller diameter than the other #1-#4. And it has 0.0004 taper on #5 alone!!!

The other 4 mains measure between 2.5200 and 2.5204, which, from what I can tell is within tolerance. (I havent found an exact measurement in a Subaru FSM, but I did see Kings state that between 2.5197 and 2.5205 is with in spec. And interstingly, "phase 1" engines are 0.0002 tighter for some unknown reason. Perhaps a rounding error when cobverting Metric/Imperial or some other weird reason???

It is pretty well established that when you do up ARP case bolts to full torque, the main tunnel distorts heavily. And I have spoken with 3 other people who have had crankshafts physically lock up when torquing ARP case bolts because the distortion closes up the clearance. The measurements I have with #5 seam to confirm the distortion is a real thing.
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Old 10-13-2018, 10:59 AM   #36
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And to top my amazing day off. One of the small M8 outer case bolts pulled the threads. I was torquing it up as per the ARP instructions and just as I got to the specified torque of 25ft pound, there was a loud pop. Initially I thought i snapped the bolt, so I backed it out, and it was fine, so I re-installed it and it would not tighten up, instead just free spinning in the hole. So the threads in the case have been pulled. **** yeah, just what I need. Now, interestingly. The 2 OEM locating dowels have been replaced by the shop. There are new dowels in the case. Which is very nice of them. They probably had difficulty removing the original dowels in order to take the parting face cut. So that is understandable.

BUT. They are longer than the OEM dowels. So, I suspect they had to drill the recieving bore a little bit deeper. IF this is the case, then it would explain why the threads might have pulled. They would have had to drill out some of the threads in order to install the longer dowel, so that would leave less threads behind, hence have a greater chance of pulling the threads when torqued up to the up-rated ARP spec. Guess what. The one that pulled is one that recieves the dowel on the top front corner... I dont have proof of this yet, and it was me that pulled the thread. But its a big coincidence that there are new dowels in my case, which are visibly bigger, and the one that pulled was one that had the bigger dowel....

The second dowel on the Subaru case is in behind the gearbox mating surface. And it cannot physically have a torque wrench put on it. The only way to do it up is with a ring spanner. So this one I didnt properly torque, instead doing maybe 80-90% by feel. So that may have saved it from pulling out aswell.

I dont think the outer circumference case bolts are quite as critical as the case bolts that secure the main tunnel. But it still sux the big one. I think i might drill and tap to 3/8 and by a high grade fastener to replace it. I dont like using a helicoil for that, as it probably wont take the up-rated torque anyways. Those ARP case bolts arent cheap, not using one will be like not using a $50 note.
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Old 10-13-2018, 12:19 PM   #37
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no biggie, just put a helicoil in there it will be fine
its quite common to strip the threads with the ARP bolts on those outer M8s, but they have no effect on mains so don't worry about it

as for the mains distorting using the ARP case bolts, I measured it last time when I was building my engine and I can tell you it changes quite a bit, especially main #5
but then you slap on torque plates and measure the mains again (in case you run ARP or any other headstuds) and you get a totally different picture again
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Old 10-14-2018, 01:34 AM   #38
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I wanted them to perform the line hone with the head studs in and torqued aswell. But they said it wont have any meaningfull effect. I also asked Andre at HPA forum and the consensus over there was it wont make any difference.

So, it was done without torque plates / cylinder heads installed.

I am using 14mm RCM bolts, these are like the biggest baddest MoFos for Subaru, so if any bolts are gonna distort things, it will be them.

Doing the line hone with head studs torqued probably wouldnt have made any difference. They probably would have forgotten to torque them all anyways...
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Old 10-15-2018, 10:22 AM   #39
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Yeah, Jim Justice (fomerly Darton Sleeves East, now at IAG) complained about how 14mm studs distorts the mains on EJ's and would machine them with torque plates.

I've personally never run 14mm studs.
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Old 10-15-2018, 11:04 AM   #40
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Im starting to think 14mm studs might not be the best choice. I read an interesting piece on how fasteners work. The basic jist of it was :

The thicker the fastener, the more strength it has. This means the fastener can be tightened up more and exert more clamp load.

But, there is only so much clamping load you can put on a soft aluminium block/head before the clamp is too much.

The way fasteners exert clamp load is by physically stretching them. You basically stretch them like an elastic band. And that elastic stretching of the fastener is what gives the clamping force.

Now this is the interesting part. A thick fastener doesnt get elastically stretched as long as a thinner one in order to achieve the same (or similar) clamp.

So when you are using thicker bolts. If the block, the head, or the head gasket or even the stud relaxs a little bit, then the thicker fastener will lose its clamping load faster than a thinner bolt that is stretched longer to achieve the same/similar clamp.

But then. There are other things to consider. A thicker fastener has more thread surface area to engage with the alloy. A thicker fastener will relax less itslef.

And to do with thread engagement. When you stretch a threaded fastener. The actual threads becone more spaced out. So in this puts uneven force distribution on the corresponding engaged threads. With the ones closer to the surface take way more force than the ones at the bottom of the hole. So, if you use a fastener that stretchs less, then the uneven loading on the engaeged threads will be reduced. Meaning the force is distributed better over a larger area.

Dunno. Too much to think about. Im pretty sure the 14mm studs are considered the best over here in Aus, and in NZ and UK for Subarus. But who really knows whats best.
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Old 10-15-2018, 08:13 PM   #41
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Heres some pics from the engine/bolts when I discovered they had not torqued the 5th pair for the line hone.

And these are the measurements of the tunnel once the 5th pair of bolts are torqued.

#1 = 2.5200
#2 = 2.5202/3
#3 = 2.5202/3
#4 = 2.5203
#5 = 2.5188 / 2.5192 (0.0004 taper on #5)

Measured at 20/21c

2018-10-13_11-17-30 by bram biesiekierski, on Flickr

2018-10-13_11-17-45 by bram biesiekierski, on Flickr

2018-10-13_11-17-57 by bram biesiekierski, on Flickr

2018-10-13_11-18-08 by bram biesiekierski, on Flickr

2018-10-13_11-18-42 by bram biesiekierski, on Flickr
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Old 10-15-2018, 08:19 PM   #42
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The shop wants to inspect the block and are happy to re-do the work.

Will they need to re-face the parting surface? Or can they simply re-hone it as is?

My worry is that the middle 3 mains are already to size, and any more honing will bring them over. I am no machinist, but to me, when a hone is done, be it on a cylinder bore or a main tunnel or whatever. The hone will always do more to the middle of than the edges. As the hone is always in contact with the middle, but patially in contact with the edges. So if this is so, then the middle will only get worse.

Then if they have to face the parting line, then more material is removed. Oil covers and rear seals become harder to fit. And piston deck hieght reduces.
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Old 10-15-2018, 10:07 PM   #43
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Case bolt torquing being a 3 step process, the shop missed the rear bolts 3 times? Bottom line is, Suby's should never be line honed. Especially with .002" o.s. bearings. You can't line hone the rear seal bore back to stock diameter either. ARP case bolts have a major effect on the bore size. As do 14mm head studs to a smaller degree. Your block cannot be simply torqued back up to hone just the rear bore larger, can't be done. Line honing is impossible to use accurately on a block with varying journal widths and beginning diameters like Subaru. The narrower ones will get to size sooner than the rest. Youtube is your friend if you want to learn about Subaru line boring.
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Old 10-16-2018, 12:10 AM   #44
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Quote:
Originally Posted by Barney145 View Post
Case bolt torquing being a 3 step process, the shop missed the rear bolts 3 times?
Yes. You are correct. The incompetence is mind boggling.

The only logical explanation is the machinist has lost 2 fingurs in a previous work place accident. And as such, lost the ability to count to 10 without taking his boots off.
Quote:
Bottom line is, Suby's should never be line honed. Especially with .002" o.s. bearings. You can't line hone the rear seal bore back to stock diameter either. ARP case bolts have a major effect on the bore size. As do 14mm head studs to a smaller degree. Your block cannot be simply torqued back up to hone just the rear bore larger, can't be done. Line honing is impossible to use accurately on a block with varying journal widths and beginning diameters like Subaru. The narrower ones will get to size sooner than the rest. Youtube is your friend if you want to learn about Subaru line boring.
Im not using 0.002 bearings. I am using ACL bearings in standard size. Atleast, i was going to.

The rear oil seal isnt honed. It is bored. So in theory, it can be re-bored if the gap close up too much.

If its impossible to accurately hone a subaru block, (differeelnt main widths), can you please explain the process Subaru use when manufacturing these engines.
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Old 10-16-2018, 03:14 AM   #45
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did you read this thread? I mean Dale explicitly explained the process in the OP and linked his youtube channel where he explains the process of line boring

you could probably get rid of the taper by hand with a special tool and mix/match bearings trying to hit the desired clearance, but its really a half-ass way of doing it

decking the halves and line boring it again is a proper way (you need to take off very little amount which is not a big deal), or get king OS bearings and just line bore for them
this time assemble the block yourself and make sure to use torque plates, especially given the 14mm studs
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Old 10-16-2018, 04:24 AM   #46
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Quote:
Originally Posted by Hyper View Post
did you read this thread? I mean Dale explicitly explained the process in the OP and linked his youtube channel where he explains the process of line boring

you could probably get rid of the taper by hand with a special tool and mix/match bearings trying to hit the desired clearance, but its really a half-ass way of doing it

decking the halves and line boring it again is a proper way (you need to take off very little amount which is not a big deal), or get king OS bearings and just line bore for them
this time assemble the block yourself and make sure to use torque plates, especially given the 14mm studs
Video is unavailble. It no work.

Block is at shop now. He didnt say what he was going to do in order to get the last main back to spec. He wants to measure it himself and then go from there.
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Old 10-16-2018, 05:24 AM   #47
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We dont have a large range of quality machine shops in my part of the world. Even less willing to do the job, and clearly even less again that are capable of doing the job. Half the guys slapping Subarus together over here dont even know what line honing or line boring is. What am i supposed to do???

The ARP isntructions say to get an align honing performed. They dont say get an align bore done. There wasnt anything wrong with my tunnel that required boring or honing, except for the use of ARP bolts which are well know to clamp the case in and tighten up the bearing clearance. And then then the dickheads doing the CNC work dented the case parting surface and mush-roomed metal into the main tunnel.

To give you an idea of the quality of machine shops around me, (who are supposed to be the recommended pro's BTW) It took over 8 months past estimated finish date to have the CNC close deck and CNC pinned main tunnel work performed, by the only shop in the state (this side of the country) doing it. I get the block back and it looks like its been to Bagdad and back, with dents and dings all over it. And am charged more than quoted.

I then drive over an hour to a shop that claimed they could do the hone to accept the ARP bolts, and fix up the dents etc, and they do it without tightening the bolts.

All I want is the tunnel with-in tolerance and fairly well uniform. It doesnt have to be perfect down to the last ten thou.

What i would like to know know, is what is the best coarse if action, given my situation.
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Old 10-16-2018, 05:38 AM   #48
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try this

https://www.youtube.com/user/motion24527/videos

I feel your pain with regards to parts of the world that don't have the equipment, skills or simple will to perform it properly, I have been in the same boat
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Old 10-16-2018, 03:12 PM   #49
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"The rear oil seal isnt honed. It is bored. So in theory, it can be re-bored if the gap close up too much.

If its impossible to accurately hone a subaru block, (different main widths), can you please explain the process Subaru use when manufacturing these engines."

The blocks are line bored from new, never honed. The rear seal diameter needs (should) be bored back to 103mm. Even if the cases were only surfaced .002" each, that's a .004" out of round seal diameter. Even without a special made fixture for holding the block dead vertical to the mainline, the block could be mounted in a vertical mill, leveled on the bell surface, centered/indicated off the rear main and then the seal diameter can be re-bored. But that operation is the least of your worries IMO. Imagine the pulling force those 14mm studs have on the block, pulling the that soft aluminum mainline in different directions. The out of alignment is something you cannot measure. The block needs to be bored with the plates installed. Or if the plates are not opened up for 14mm, install a pair of heads. The plates do not interfere with mounting a Suby block in the line hone machine. But, it shouldn't be in that machine in the first place!
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