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Old 12-14-2012, 08:55 PM   #51
jamal
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You need to do a leakdown test. I've found that things have to be pretty bad (like a missing chunk of ringland) to see much of a drop in compression.
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Old 12-14-2012, 09:18 PM   #52
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Quote:
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You need to do a leakdown test. I've found that things have to be pretty bad (like a missing chunk of ringland) to see much of a drop in compression.
True - would a leaky valve seal show up on this? If a leak down test returns a bad value - how does one determine which part of the motor is to blame?

It's obvious to me something isn't right internally - rings or valve guides/seals - one way or another it needs to come out.
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Old 12-14-2012, 11:26 PM   #53
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Doubt its the head, you said you took it easy for 1000 miles, poor ring seal is most likely the problem.
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Old 12-15-2012, 12:43 AM   #54
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Originally Posted by Flat 4 Motorsport View Post
Doubt its the head, you said you took it easy for 1000 miles, poor ring seal is most likely the problem.
That's a possibility as well. However - wouldn't that render significantly lower compression numbers?
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Old 12-15-2012, 01:07 AM   #55
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That's the other point of the leakdown- you can tell what is leaking
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Old 12-15-2012, 04:29 AM   #56
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AOS has nothing to with my scenario. I was saying that the smoke increased many fold when I removed vacuum from the crankcase. Pretty good indicator of excessive PTW clearance/poor ring seal in my case. The vacuum from the intake was acting as a bandaid and masking the issue. The compression was still decent but power began to suffer later on.
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Old 12-16-2012, 01:50 PM   #57
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New question: When I installed my new VF43, I boosted the car within the first 5-10 miles or so. Any chance this damaged the seal on my new turbo, and perhaps the new turbo is now burning oil too?

I've read mixed reviews about how to break in a turbo. My understanding though is that if a turbo *really* goes, it will be smoking all the time, clouds of smoke, even at idle.
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Old 12-16-2012, 02:02 PM   #58
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Any damage would be to the bearing not the seal. It's not the turbo dude

Last edited by aboothman; 12-16-2012 at 10:51 PM.
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Old 12-16-2012, 02:30 PM   #59
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Any damage would be to the bearing not the deal. It's not the turbo dude
Fair enough - that was what I figured as well. Thanks.
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Old 12-16-2012, 02:50 PM   #60
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Plus the seal is kind of hard to damage. Think piston ring, not rubber o-ring so things have to go pretty wrong for a turbo to blow up. The thing is it doesn't really hold a lot of pressure and will let oil go by if it is getting too much oil or excessive crank case pressure is not letting oil drain out of the cartridge.

But honestly just have a leakdown test done. Otherwise we're all just going to sit around and guess.
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Old 12-18-2012, 04:38 PM   #61
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At this point I'm wondering if I should skip the leakdown test and just go straight to pulling the motor. I'm 99.9% sure it's not the turbo, and I actually don't have a compressor so I cannot perform a leakdown at home. I have never pulled an STI motor before, but I've done probably more than half the needed things to do considering the number of installs I've done over my STI modding career. I'm thinking about pulling it at home in my garage, then shipping it in stripped-down longblock form to my builder for inspection/repair.
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Old 12-20-2012, 10:52 AM   #62
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Question - is this turbo drain line considered to be "kinked"? Both clamps are on very solid, but I've read if this drain gets clogged it can cause oil to get pushed past the seals. I'm just doing a quick scan of all my lines before pulling the motor, and I'll be doing a leakdown test today as well.

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Old 12-20-2012, 11:05 AM   #63
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Quote:
Originally Posted by Acejam2k View Post
Question - is this turbo drain line considered to be "kinked"? Both clamps are on very solid, but I've read if this drain gets clogged it can cause oil to get pushed past the seals. I'm just doing a quick scan of all my lines before pulling the motor, and I'll be doing a leakdown test today as well.
Nah that is about as good as it gets on a stock location turbo
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Old 12-20-2012, 05:15 PM   #64
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I had a leakdown test done today, results are as follows:

#1: 6%, 144psi
#2: 3%, 140psi
#3: 5%, 150psi
#4: 2%, 144psi

There was no noticeable hissing or air leaks, so we were not able to pinpoint any specific intake or exhaust valve issues. Regardless, I am looking to pull the motor starting tomorrow night and will be sending the longblock off to my builder for inspection.
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Old 12-20-2012, 07:51 PM   #65
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Quote:
Originally Posted by Acejam2k View Post
I had a leakdown test done today, results are as follows:

#1: 6%, 144psi
#2: 3%, 140psi
#3: 5%, 150psi
#4: 2%, 144psi

There was no noticeable hissing or air leaks, so we were not able to pinpoint any specific intake or exhaust valve issues. Regardless, I am looking to pull the motor starting tomorrow night and will be sending the longblock off to my builder for inspection.
I wouldn't touch it with those results, your call though.
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Old 12-20-2012, 09:02 PM   #66
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^+1 to that
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Old 12-20-2012, 09:44 PM   #67
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I wouldn't touch it with those results, your call though.
The turbo is brand new though. Where else could the oil be possibly going? Our guess is that its a leaky valve seal or guide.
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Old 12-20-2012, 09:50 PM   #68
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Originally Posted by Acejam2k View Post

The turbo is brand new though. Where else could the oil be possibly going? Our guess is that its a leaky valve seal or guide.
It's brand new but that doesn't mean much, if you pushed the seals installing iy
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Old 12-20-2012, 10:03 PM   #69
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It's brand new but that doesn't mean much, if you pushed the seals installing iy
Pushed the seals installing it - do you mean blowing a seal by giving it too much throttle too early?
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Old 12-20-2012, 11:28 PM   #70
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Quote:
Originally Posted by Acejam2k View Post

Pushed the seals installing it - do you mean blowing a seal by giving it too much throttle too early?
No but after reading your whole story it doesn't seem the turbo is the culprit. Your sure the PVC lines are routed correctly and PVC valve is correct?
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Old 12-21-2012, 01:18 AM   #71
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No but after reading your whole story it doesn't seem the turbo is the culprit. Your sure the PVC lines are routed correctly and PVC valve is correct?
I am going to pull all the crankcase breather lines tomorrow to double check. My PCV valve is deleted though - it was removed during the Crawford AOS install.

Essentially the lines I am concerned with are:

- All Crawford AOS breather lines
- TMIC Metal Pipe
- 4 Valve Cover breather hoses (2 small ones, 2 big ones)

What else?

I have run hot water through my AOS, but I will pick up some more carb cleaner and properly clean it out as well. I actually just finished up assembling my new engine stand and hoist, but I will re-check all of these lines first before pulling anything.

In order for there to be excessive crankcase pressure to the point of oil getting pushed past a seal - it would have to be pretty severe, correct? ie: Completely plugged/kinked line.
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Old 12-23-2012, 06:06 PM   #72
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I pulled the motor yesterday, and it stripped it down to a semi-bare longblock. I'll be shipping it out to my builder on Monday or Wednesday. It was my first motor pull ever and it went very smoothly.

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Old 01-02-2013, 09:20 PM   #73
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My motor is now at my builder and will be looked at tomorrow.

On another note - I was in my garage today going over some parts. My turbo was sitting sideways/upside down for the past couple days with the hotside facing towards the floor. I picked it up, and just saw what appears to be wet oil on the exhaust wheel. I'm not sure if it's oil yet, I will look closer.

My question is - if the turbo is disconnected and unusually positioned like this for a couple days - is any type of oil leak expected/normal?
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Old 01-03-2013, 01:04 AM   #74
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I guess expected or normal is dependent on what the final verdict is. You already told me you had forged pistons. But when ring #4 went out for me(stock pistons), I had oil everywhere..according to my builder, like a half cup in the IC, about the same in the DP and around maybe a 1/4 cup in the turbo after it was left to "drain" during the whole rebuild.
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Old 01-03-2013, 04:27 PM   #75
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The motor was taken apart today. We found signs of significant overfueling in the cylinders. The bores are shiny, and it looks like some of the rings didn't fully seal. According to my builder it was also apparent that cylinder #4 was the one burning the oil. My current tune is for 11.0:1 AFR which is what many tuners use in the Subaru world. My old tune that I used for the first 1000 miles and break-in was in the mid-10's, but that's still leaner than stock/Cobb OTS map. My guess is that maybe my old tune has some type of weird fuel enrichment at startup that caused the bores to get washed out and glazed, causing the rings not to seat correctly. The fuel essentially acts as sandpaper and causes the rings to become sharp as well.

The rods and pistons appears to be OK. The pistons have typical wear on them, and one of them has some light scuffs, but can probably be re-used without issue. We are currently waiting to hear back from the machine shop to see if we can lightly hone the cylinders or not. If we can't and we need to bore it out, we'd need new pistons.

On a similar note, my rear thrust bearing appears to be completely trashed as well. We're not fully sure how this happened, but my builder mentioned that a bad clutch or dropping the clutch/launching the car can causes this. This bearing failure caused the crank to essentially walk, and the crank pulley on the front was rubbing on the face of the oil pump. The seal on the oil pump was almost done and about ready to explode.

Overall I'm looking at all new bearings, crank, and probbaly some machine work for the cylinders. Luckily the remaining bearings appear to be OK, but we will probably replace all of them for good measure.

If the costs add up too much, then I am debating on just picking up a new Street Series block. Essentially that will be a brand new EJ257 shortblock with drop-in CP pistons. This is a great combo and I ran one of these for my last block for 2+ years and over 25k miles. The only "downside" is that they feature stock bearings, and the pistons are drop-in's. The pistons will be a bit on the louder side. The stock bearings are very good quality, but the clearances that Subaru uses can sometimes be off - so it's pretty much luck of the draw on which block you get from the factory.

After all the money that I have put into this car, a new 2013 STI is sounding pretty nice. However, I'd probably end up with a cracked ringland in that car eventually too.
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