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2006 Forester XT Limited 4EAT
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2,000 Posts
Discussion Starter #1 (Edited)
Well here are the numbers:

Compression Dry(psi):
115 130 145 140
Compression Wet(psi):
125 135 150 145
Max difference is 30psi & 7psi is acceptable.

Leak Down Test(%):
65 23 8 10

Was getting sporadic CEL P0301 Misfire Cylinder 1 paired with rough idle. Occurring mostly upon restart after car was already warm. Losing oil as well.

Time to pay the piper, I'll keep this updated as I clean it up.

UPDATE 9/10/10
Had another leakdown test performed by an independent shop. I watched the whole thing to verify the numbers.
Results were 5 18 5 14
Pretty big difference, but still was loosing about a quart of oil every 1.5 weeks. Who knows why Irvine Subaru got such different values.

Pulled the engine and found the culprit to be badly fouled valves and seats on the exhaust ports. All cylinders were also out of round. Plan is, bore the cylinders to 100mm and install Manley forged pistons. Top the deck and heads. Obviously a valve job replacing items as needed, nothing special there.
More to come.
 

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2006 Forester XT Limited 4EAT
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2,000 Posts
Discussion Starter #4
I don't know at this point. Looking back, I want to say there were indications, but that may just be armchair quarterbacking...
 

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2005 Forester XT 4EAT
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2,160 Posts
Looks like you're gonna have to join me in the rallispec shortblock club :rock:

RalliSpec - Engine | Short Block

I know how you feel, it sucks when those results come back bad, but now it's just an excuse to make your forester that much more bad @$$
 

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Premium Member
2008 FSXT 4EAT
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4,143 Posts
Damn, sorry to hear. Is it just me, or have several members' motors crapped out recently? Makes me nervous to use the go-pedal... :icon_eek:
 

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2004 FSTI automatic
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2,643 Posts
Dang Chris, Sorry to hear bad news...Keep us posted on what you find after you (they) open it up.

Like you said...lots of speculation, but won't know till then.

Dunno if this is in your budget....but since they are local, could be worth it.
Crawford Performance

First Crawford sponsored Foz....I can see it now!! :crazy:
 

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2017 VW Golf SportWagen 5MT
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10,784 Posts
What's your tune like? What turbo?

Suck man, but it'll be better than before once it's all fixed. Our stock pistons suck, if anything happens to my engine I'm getting forged ones.

Stan
 

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2004 FSTI automatic
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2,643 Posts

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2006 Forester XT Limited 4EAT
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2,000 Posts
Discussion Starter #11
yeah, ~360/360 w/ Dom 2.5XT-R
Definitely going forged pistons, may swap the engine. Depends on what she looks like inside.
Keep the info and links coming!
 

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2004 Forester XT MT
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1,433 Posts
Whatever the cause, make plans to seize the opportunity to do other mods while the motor is out (flywheel, clutch, motor and transmission mounts, timing belt, water pump, oil pump, turbo inlet, heat wrap, etc.). You'll save money by paying labor only once.

Before going forged, take a ride in few cars that have them. It's a love it or hate it thing. The noise and warm up time don't bother me but could seem like a nuisance to others.
 

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2004 FSTI automatic
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2,643 Posts

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2004 Forester XT MT
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2005 Forester XT 4EAT
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2,160 Posts
Too bad the AFR logged wasn't from a wideband. I'm not an expert at reading logs. My guess is that the AFR dipped into the 10's when the log went static at 11.15. An AFR of 11.0 or greater is consider safe, right? AFR into the 10's starts to get to an edge tune?
Dipping into the 10's would be a rich condition which while not good i would think is safer then a lean condition that would be upper 11's into the 12's right?

Also for added input, i researched many blocks and options when my rings blew, and the rallispec block just seemed to be the best bang for the buck. You get a brandy new block, forged pistons, rods, race bearings, and a fancy new nitrate coated STi crank, and there's many members on nasioc with these blocks (one guy with 23,000miles already) and they all love them.
 

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2008 FSXT 4EAT
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4,143 Posts
Too bad the AFR logged wasn't from a wideband. I'm not an expert at reading logs. My guess is that the AFR dipped into the 10's when the log went static at 11.15. An AFR of 11.0 or greater is consider safe, right? AFR into the 10's starts to get to an edge tune?
Are you you referring to the dangers of running too lean? Wouldn't a conservative tune have a lower AFR (richer), at the cost of leaving some power on the table?

Edit: I was too slow... lol
 

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04 SOLD!
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944 Posts
I remember in the log you posted back a few months ago, there was some knock at some point to put your IAM down to .81, also the ignition timing looked a little strange. It was hard to tell by the log though since I didn't see throttle position logged. Any leakdown/compression tests done before you got tuned?
 

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2006 FAXT 5mt
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525 Posts
i have a 06 XTL @64,000 miles it started to run rough mech. did a leak down test failed on one of the cylinders turned out to be the smog pump solinoid sticking open . this caused the exhaust valve to get hotter than it should and that caused excessive wear on the valve guide . as a result leak down test failure. rough motor.
 

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2006 Forester XT Limited 4EAT
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Discussion Starter #19
I remember in the log you posted back a few months ago, there was some knock at some point to put your IAM down to .81, also the ignition timing looked a little strange. It was hard to tell by the log though since I didn't see throttle position logged. Any leakdown/compression tests done before you got tuned?
No....But looking back I really should have. I thought the throttle body to TMIC coupler was the problem and left it at that...:crazy:

i have a 06 XTL @64,000 miles it started to run rough mech. did a leak down test failed on one of the cylinders turned out to be the smog pump solinoid sticking open . this caused the exhaust valve to get hotter than it should and that caused excessive wear on the valve guide . as a result leak down test failure. rough motor.
So, what was your fix? What was replaced?
 

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05 FXT
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1,540 Posts
Mine finally popped as well.

I'm pretty sure mine was a function of heat soak. I was running it hard, and then after making a pull all the way through 4th gear, I got an ugly puff of smoke and some sputtering. Didn't think much of it at the time, and it seemed alright afterward minus an occassional miss at 2,500 rpm. No more than normal oil consumption or smoke.

Well, finally got around to compression and ~30psi low on one cylinder. Quite certain it's ringlands for me. I blame it on a combination of pushing over 300 at the wheels, STI TMIC at that power level, and 95+ degree weather.

Doing the build myself, going to throw Mahle's Powerpacks in mine. I'm a customer of Mahle at work, so I'll stick with them for my personal vehicles as well.
 
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