04 subaru sti burning oil and rough/high idle issue

Bigmerk215

New member
Whats up everyone just wanted to get a few suggestions before i tear my motor apart again. Still trying to fix this car after almost 9 months of throwing parts at it. Initially the car appeared to have blown head gaskets and excessive blow by.

Pulled motor. Replaced every gasket, had heads sent out to be decked and valve seats resurfaced and inspected. New timing belt, tensioner, and water pump. Badically everything besides the bottom end.

Motor put back in car and still burning crazy oil but no coolant smell or overheating anymore.

Blows alot of smoke out of the exhaust and was smoking around the turbo. Looks like i may have some blow by too.

compression and leak down numbers came back as: (forged 8.2 low compression pistons)

cylinder 1: 115 psi 3% leakage
cylinder 2: 115 psi 10% leakage
cylinder 3: 115 psi 2% leakage
cylinder 4: 95 psi 10% leakage

only cylinder number 4 i am concerned with. 120-130 psi would be ideal for these pistons. Me and my mechanic decided the motor shouldnt be running this poorly even with these numbers. The turbo appears to be making a fluttering noise also.

So i replaced my old gt30 with a new gt3071r ball bearing turbo.

Still same oil consumtion issues and what appears to be a turbo noise.

I estimate this engine has about 20k miles on it. Build was finished in 2013 with brand new block and heads assembled from the ground up. 20k in reciepts for the build (previous owner paid this bill).

My only other ideas would be a bad oil pump or tear the motor apart again. This time sending the bottom end out. Any suggestions woukd be appreciated.

thanks
max
 

Alin

Diehard Car Enthusiast!
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[MENTION=5855]Bigmerk215[/MENTION] when you took the heads off what did the Pistons look like? Any chance that you snapped a picture of it? Sounds like you did most of the standard stuff when checking for oil consumption. Only thing I can think of is that the oil rings are not sealing correctly on the pistons. When you had the heads done did you have the valve guides and seals checked as well? Don't think that the oil pump would cause bad oil consumption either. Also what type of bypass valve are you using. Is it working correctly? I ask this because of the fluttering that's you mentioned. I once had the stock BPV get plugged and had the same effect and it ended up blowing the oil seals on a vf39. If you could get a video of the sound that would be helpful.


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Bigmerk215

New member
I could only see tge top of the pistons and the cylinder walls. Cylinder walls looked a bit glazed but nothing irregular. Top of pistons just showed signs of running rich but nothing significant. I do have pictures that i can post when im able to post from my computer. Only reason i suggested oil pump because turbo seems it isnt getting enough oil pressure and smoking and was making irregular noises. All valves and seats were check and recut. Heads were tore down, cleaned, and new valves seals installed. Heads are near brand new to begin with but i like to take extra precautions and do things right the first time. Not sure what you mean by bpb? Do you blow off valve? I run an afternarket hks bov flutter type. Dont think thise is the issue. Just want to rule every other possibility before i tear this thing apart.
 
Bypass valve. Re-circulates back into the system. This is the stock configuration. Blow off valve is a vent to atmosphere. Also what type of boost controller are you using? Just trying to figure out the reason for the turbo flutter. Also, is there any oil in your intercooler lines? If so have you checked your PCV to make sure its not stuck open? Finally, when you can get to a computer please post the pictures. Thanks.


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Bigmerk215

New member
I have a manual boost controller. Pcv has been replaced with a catch can. And there is oil in the intercooler/intake piping.
 

Alin

Diehard Car Enthusiast!
How much oil? Is it pooling inside the intercooler and intake?
 
I would put a PCV back on in line with the catch can. The pcv has a check valve in it to prevent oil from the crank case escaping and going into your piping, intercooler etc. it also prevents you from pressurizing your crank case if the line still connect to you intake manifold.


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Also clean out the oil in all the pipes and the intercooler and check it again in a week to see if the oil is still getting in there.


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So thinking about this for the past hour or so I realized I really don't have all the information here. That being said can you get us some pictures of your engine bay and pcv system and how it's hooked up. Thanks.

The reason I ask this is since you have a catch can in there instead of a PCV there might be other configuration changes that were made that I am un-aware of that may be causing you the issues you are experiencing.


Raven


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Bigmerk215

New member
IMG_4793.jpg
 

Bigmerk215

New member
The bottom connection goes to my intake pipe where the maf sener is. Right side connection goes to the engine block on the back and the front connection splits into a T fitting and goes to both of the heads
 
ok so it possible that you are getting oil back in your intake track from the catch can setup as it has not check valve to prevent the oil from going into the intake. That being said, I would try cleaning the intake, intercooler pipes, intercooler out of any heavy oil deposits. Then put a PVC in line. However, don't know if it should go on block or get one that can go between the in intake can catch can. By default the vacuum of the intake will draw the vapors out of the block and heads.

Also wouldnt having the hose from the bottom, where all the oil sits in the catch can, cause the oil to go directly into the intake?
 

Bigmerk215

New member
Well Im opening this thread back up since I continue to have the same issues with a brand new short block installed. Motor fired right up after a few cranks but still get a ton of smoke and high idle. Definetly seems to have excessive crank case pressure. Brand new short block, heads have been redecked and refreshed/inspected for leakage, new garrett gt3071r ball bearkng turbo, all new gaskets and hardware throughout. My next move is to have it towed to a subaru specialist thats local to me called PSIProformance. They are also the ones who built the shortblock. Any suggestions would help put my mind at ease.

Thanks
 
Well Im opening this thread back up since I continue to have the same issues with a brand new short block installed. Motor fired right up after a few cranks but still get a ton of smoke and high idle. Definetly seems to have excessive crank case pressure. Brand new short block, heads have been redecked and refreshed/inspected for leakage, new garrett gt3071r ball bearkng turbo, all new gaskets and hardware throughout. My next move is to have it towed to a subaru specialist thats local to me called PSIProformance. They are also the ones who built the shortblock. Any suggestions would help put my mind at ease.

Thanks

What pistons/rings were used?


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You get a build sheet with clearances? If so please post it.


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