Engine/Turbo Issue
 

Hey everyone,

I feel guilty posting this, but I'm facing some strange issues with my recent build where the center cartridge from the turbo is smoking and I'm getting oil smoke from the tailpipe. I need this fixed asap to be able to take my car to my bachelor party. I'm not the most mechanically savvy person but I just am not exactly sure what steps to take from here, whether it's engine related or turbo related.

ECU: DIYPNP

Engine: 96' unknown miles, brand new oem PVC from a 323 gtx to a sealed catch can, to the intake manifold. Intake breather is plumbed to intake pre turbo. Running 5w30.

Turbo: Recently rebuilt and balanced sr20 turbo, have tried no restrictor, 1.5mm and 1mm. No blockages in drain or on the turbo itself, and drain is straight down to the pan with no kinks. It ONLY leaks on the exhaust side. Compressor side is bone dry. I've tried 2 different exhaust piston seals. Running wastegate 6 lbs boost.

Compression:
Dry
1. 200
2. 170
3. 200
4. 180

Leakdown:
1. 4% leakage, heard from the oil cap (rings)
2. 4% leakage, heard from the #4 cylinder spark plug hole, also from the exhaust pipe
3. 6% leakage, heard from #4 cylinder spark plug hole, also from the exhaust pipe
4. 5% leakage, heard from #3 cylinder spark plug hole, also from exhaust pipe

Tailpipe smoking:

Exhaust pops/miss at idle

Extra info..
I've done the test where you open the oil cap at idle, place a sheet of paper over, and it flapped around like crazy. I'm not exactly sure what this accomplishes.
I haven't replaced valve stem seals on this engine, but they've never given me an issue before and I've tried high vaccum situations (engine brake) to throttle and haven't seen any smoke from the tailpipe.
I've also read the thread regarding modifying the valve cover for higher flow to help deal with blowby/pressure, and have taken none of these steps *yet*. I'm thinking this is next but want to make sure I'm not chasing my tail.

Thanks in advance.

Two different exhaust piston seals?

Yessir. It’s the exhaust side seal to keep oil out of the exhaust and into the CHRA where it should be. At first I thought it was maybe installed with the gap facing downward which would let oil just drain right out. But that wasn’t the case, and I got a fresh one for good measure. It all checked out though. Sorry for the huge picture, I can’t tell if it’s uploading at a normal size or not.

https://cimg5.ibsrv.net/gimg/www.mia...d45439f1e.jpeg
The seal in question.

So, you installed the seal yourself but had the rotating assembly balanced by a shop? They did not install the seal?

I installed the seal onto the shaft itself but when I sent it off to GPOP they did the balance and final assembly “popping” the shaft into the CHRA and seating it. When I replaced it the second time I put this upgraded one in with the hope that the design of the original seal was just naturally letting some through. I’ve read others threads where it’s just taken some time for it to “act right” and so I put about 150 miles on it but it’s still doing it even with this step gap seal.
https://cimg2.ibsrv.net/gimg/www.mia...41f5eae15b.jpg
Upgraded “step gap”
https://cimg8.ibsrv.net/gimg/www.mia...a9233b13f.jpeg
Fits like a glove.

Another worthy mention is that my oil feed setup is a -4 line.

500+ mile update. I went ahead and switched down to a -3 oil feed line and am using the pop-rivet restrictor trick. Under normal driving with little boost, it's almost perfect. If I boost around and let the cool car down, I can wipe a paper towel underneath the CHRA and get very little oil on it compared to before. I believe that at this point I am probably facing more of a blowby problem and am going to plan on doing some valve cover mods.. the 'small hole' mod. Hopefully that'll get me to 100%.

Thanks all for the help / suggestions! :party: