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Old 07-07-2009, 10:45 AM   #1
whatishe
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Default Spun bearing on my EJ207

And it had all gone so well..... I scored a prebuilt 207 from another member with forged internals, v7 crank, built heads, etc and I ran it on a street tune for ~1500 miles. It has all the proper break in procedures followed, but apparently the clearances were off for cylinder 3's bearing (too lose) which spun this weekend . Luckily, it failed in such a way that I'll only have to have the crank repaired, but since I have to tear down the block, does anyone have any recommended upgrades?

I will have to replace the gaskets, studs, and all bearings. I've also read that I should replace the oil pan, pump, etc. I already have forged pistons, rods, double springs, sti valves, and 280 cams. Should I get a TGV delete done while the engine is apart? Port and polish? Any recommendations? I DO NOT plan to take this engine apart again if I don't have to. LMK, thanks!
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Last edited by whatishe; 07-07-2009 at 11:29 AM.
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Old 07-07-2009, 01:52 PM   #2
madmax718
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Odd... it spun cause it was *too* loose?
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Old 07-07-2009, 02:25 PM   #3
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Sorry to hear this.

Uprated head bolts and a replacement Modine as i wouldn't re-use the contaminated modine again.

Oil Pump is an interesting one as i would have thought if your valvetrain had been upgraded the pump would have been done to, to take benefit of the higher rev limit which is obtainable on the uprated valvetrain.
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Old 07-07-2009, 05:27 PM   #4
whatishe
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Quote:
Originally Posted by madmax718 View Post
Odd... it spun cause it was *too* loose?
Maybe lose isn't the right word; not in spec is what the "autotopsy" shows. My mechanic says it was out of spec by a significant amount, but that when it went, it kept spinning, grinding the crank down like a lathe instead of seizing and snapping the rod.
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Old 07-07-2009, 05:30 PM   #5
whatishe
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Quote:
Originally Posted by Baly View Post
Sorry to hear this.

Uprated head bolts and a replacement Modine as i wouldn't re-use the contaminated modine again.

Oil Pump is an interesting one as i would have thought if your valvetrain had been upgraded the pump would have been done to, to take benefit of the higher rev limit which is obtainable on the uprated valvetrain.
We discussed going with an uprated pump, I will most likely do it this time, but from what we can tell, the bearing would have failed either way. I guess the lesson learned here is "measure twice, built once". I am kicking myself for not having all the clearances and tolerances checked before hand. Just goes to show, even professionally pre-assembled engines fail.
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Old 07-07-2009, 06:09 PM   #6
alcoolaid
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I would have that it would have spun from being too tight?

Get a new oil cooler too if you're running it.

What were your oil pressures like during break in?
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Old 07-07-2009, 06:29 PM   #7
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Quote:
Originally Posted by whatishe View Post
Maybe lose isn't the right word; not in spec is what the "autotopsy" shows. My mechanic says it was out of spec by a significant amount, but that when it went, it kept spinning, grinding the crank down like a lathe instead of seizing and snapping the rod.
Ya, thats generally in my experience not because it was too loose. Generally this is developed from a lack of lubrication reaching the bearings for whatever reason. Looser tends to allow more oil flow, and prevent seizing longer.

Its almost impossible to check how much it was out of spec once its spun- you've lost material, and therefore the spec is all over the place- and not representative of the spec of the bearing when it was installed. No doubt that the bearing failed, just the aspect of its failure may not have been the bearing being loose. There is not enough evidence left over to decide what the problem really was.
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Old 07-07-2009, 06:32 PM   #8
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Quote:
Originally Posted by whatishe View Post
We discussed going with an uprated pump, I will most likely do it this time, but from what we can tell, the bearing would have failed either way. I guess the lesson learned here is "measure twice, built once". I am kicking myself for not having all the clearances and tolerances checked before hand. Just goes to show, even professionally pre-assembled engines fail.
Built blocks do fail, but you'd be surprised at the number of builders who do not use precision measurement tools. Not saying your builder was that way, but...

BTW, did yours come with a build sheet? The build sheet should have shown individual readings of each bearing.
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Old 07-07-2009, 10:47 PM   #9
whatishe
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Well, I'm sure it did, it was built by a very reputable shop for a member on here. When she decided to get out of the Subaru game, she decided to sell the engine. I bought it from her after it had sat for a long time but with very low mileage. I got it assembled, ready to drop in, minus build sheet. I had my shop check it for any apparent issues, but I didn't have them measure everything. I don't know the exact original mileage on the engine, but is was in the 1000-2000 range, which is break-in. We followed the break-in again after installing it in my car, just to be safe. Went to get it tuned after ~1500 miles. Went to have it tuned, mechanic noticed noise from bottom end, checked oil and found it metallic, dropped the oil pan, spun bearing. Annnnd that was my weekend. Anyway, I'm (as you can guess) not entirely up to snuff on my engine mechanics, but from what I'm told, it wasn't in spec and I'm included to believe him given his motorsports pedigree and track record. Also, he didn't build the engine, so I can't really blow up at him, not his fault. As much as I would love to not rebuild it, I feel better knowing the person doing it this time around, plus if it breaks, he owns it. While the engine is out well be doing the following:

-Stronger Rods
-Better Bearings
-New Gaskets
-Port & Polish Heads
-Upgraded Oil Pump

I'm also going to have the entire oil system flushed and cleaned and the turbo inspected. There are also plans for ceramic coating and maybe some EL headers. Hopefully we'll hit that 400 WHP mark.

Last edited by whatishe; 07-08-2009 at 10:26 AM.
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Old 07-07-2009, 10:58 PM   #10
madmax718
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oh dude, you got it all wrong here. Im not flaming anyone here for anything, so.. just the facts.

I thought this was a newly built engine that just sat around. Chevy guys used to do that all the time, just happen to have a blue printed and balanced SBC just lying around...

But in this case, it sounds as if the block was built, she had it removed, then it sat around, and then you bought it. So really, you dont know what happened during those first 1000-2000 miles. Just make sure you have the whole block checked out before you start doing anything else, or buying parts.
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Old 07-07-2009, 11:43 PM   #11
whatishe
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Quote:
Originally Posted by madmax718 View Post
oh dude, you got it all wrong here. Im not flaming anyone here for anything, so.. just the facts.

I thought this was a newly built engine that just sat around. Chevy guys used to do that all the time, just happen to have a blue printed and balanced SBC just lying around...

But in this case, it sounds as if the block was built, she had it removed, then it sat around, and then you bought it. So really, you dont know what happened during those first 1000-2000 miles. Just make sure you have the whole block checked out before you start doing anything else, or buying parts.
No, didn't think you were flaming me, haha! No worries, I just wanted to explain my situation better is all. Sorry if I came off touchy!
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Old 07-08-2009, 12:31 AM   #12
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Damn Internet!It's so impersonal !
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Old 07-08-2009, 03:10 PM   #13
whatishe
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So, some of you may be curious as to my mechanic's theory. I have quoted his email below.

Quote:
I have a theory as to why it failed, but its hard to be sure. I checked the clearance of one of the other rods that had a bearing that was fine; unscratched. The clearance measured by plastigage was .004in, the wear limit called out by our AllData program was .04mm, which works out to .0015in. There could have been a mistake by the previous machinist, or, as it appeared to me, the crank was cut. Since the bearings were of Standard size, the wrong bearings may have been installed into the engine when it was rebuilt last.... Its hard to tell because I was only able to measure one other rod bearing.

To further my theory, most American engines run clearances of .0025 to .004in so the clearances wouldn't seem strange to a machinist who builds V8's or conventional older engines. However, when you get into higher specific output engines, the bearing clearance has to decrease so that the hydrostatic pressure of the oil will withstand the load without metal to metal contact. The stress of the motor finally making power brought out problems that weren't apparent under normal driving conditions (vacuum). Or, it could be just that one specific bearing was screwed up from the beginning and it was a matter of time before it broke.
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Old 07-09-2009, 05:03 PM   #14
whatishe
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Well, this #$%^ is gonna cost a %$#@&!# lot to fix..... I may not fix it, may just put the car on blocks and torch it, haha. I'll update with my final decision. I wish I had a DD that wasn't' also my modded car...
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Old 07-09-2009, 07:58 PM   #15
madmax718
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criagslist 500 dollar beaters.

BTW, taking what he said, I still stand by my original theory- the build might have been done incorrectly. Without the build sheet, there's not much info left on how much each clearance of each bearing was. But according to another subie manual for a legacy gt 2.5 turbo (might be different for your year?)

Connecting rod oil clearance:
Standard
0.017 — 0.045 mm (0.0007 — 0.0018 in)

Your .004" was on a GOOD bearing- so who knows what else was going on in there. The bearings were way out of spec to begin with, unless someone had specified looser bearings for a high pressure oil pump, but then didn't put one in?

Last edited by madmax718; 07-09-2009 at 08:06 PM. Reason: about old american engines
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Old 07-09-2009, 08:05 PM   #16
madmax718
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those .004 is common on older pushrod engines. But even those have tightened up over the years. I just cant imagine someone building a block and calling it good. If the crank was cut, a mic of the journals would net you the diameter..

Standard
Journal O.D.
59.992 — 60.008
(2.3619 — 2.3625)
59.992 — 60.008
(2.3619 — 2.3625)
51.984 — 52.000
(2.0466 — 2.0472)
Bearing size
(Thickness at center)
1.998 — 2.011
(0.0787 — 0.0792)
2.000 — 2.013
(0.0787 — 0.0793)
1.486 — 1.498
(0.0585 — 0.0590)

So, ya, he should be able to tell you if the journals were machined, and if so, what bearing was supposed to be in there. Your supposed to machine it to the undersized bearing so...

Anyways, its just good old forensic detective work. I just wasn't quite satisfied with the answer that "oh it died", or "oh it spun a bearing"- There is a lot of info that we can all learn from your loss, and I'd hate to see that knowledge go the wayside.
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