How to test oil rings vs turbo seals burning oil on boost?

[Spoolin4Ever]

The car burns oil only on boost, and the heavier the boosting, the more oil it burns. EVO3 16G turbo, no shaft play. It boosts fine always.

I noticed some oil build up on the oil return line. The top half is not clogged, I still have to check the bottom half. I just bought some wire brushes that are the shape of pipe cleaners to put in the bottom half to check it for coked oil (it's still on the oil pan, I don't want to remove unless I have too since there's always the possibility of leaks when putting it back on). I've got the homemade setup; a stock oil return line with the center cutout and a rubber hose in the middle. I bought a $20 piece of high heat hose to use in place of the plain black one that was there.

When the head was on, I did dry and wet compression tests. The difference between dry and wet was 10 lbs, and that was on a cold engine. It had a couple burnt valves and I had already pulled the radiator and some stuff so a warm engine test wasn't really feasible at the moment. Anyway, it didn't seem that significant of a difference between the dry and wet compression tests, so it would that mean the oil seal rings are still good?

Some people have told me that an engine can show good compression, but under boost the rings could still be bad, that it just would only happen under boost (it was a machine shop that I called for a quote on the head, I ended up going with someone else). I've also heard this on other forums and online discussions.

The head is off the engine right now, for 2 new valves, I'm getting ready to put it back on.

 

[Indian]

Are you smoking? Where are you feeding the turbo from, and what type of line are you using? OEM, or aftermarket?

 

[talonDSMerr]

Any smoke coming out of the exhaust during boosting?

The compression test won't tell you whether or not you have bad oil rings. That test is for the top two compression rings. The oil rings below the two compression rings are responsible for keeping oil out of the combustion chamber and do not have anything to do with compression.

Smoke coming out the exhaust in a blueish tint is a symptom of bad oil rings. From how you explain it, you might have a small leak somewhere. Not big enough that it drips while idling, but enough that it sprays during boost and when you load the engine.

 

[doubleclutch99]

What were the numbers you got on the compression test? if you can get a peek inside the o2 housing you might be able to see if the ring on the turbine shaft is letting oil by. just a thought

 

[Spoolin4Ever]

What were the numbers you got on the compression test? if you can get a peek inside the o2 housing you might be able to see if the ring on the turbine shaft is letting oil by. just a thought

Well back when I first got this engine installed, it was around 150-155 across the board, and it's always done it. Had a new turbo put on, but I think I may have been lied to about the turbo being new because they weren't honest about a bunch of other stuff. I'm wondering if they put a turbo on there that has blown oil seal/piston ring (in the turbo), or can the compression rings be weak and leak under boost only?

Also, I have put catch cans and checked my PVC, never any extra oil in the catch can compared to what is being burnt. I never had to empty the catch can, so I removed it because of clutter, don't need it. PVC valve is good as well.

 

[SHEARER_TSI]

do a leak down test

 

[Spoolin4Ever]

do a leak down test

OK when I get it back together I will.

 

[doubleclutch99]

The manifold and inlet of the turbo looks clean. and the o2 housing looks like it has some coking i'd lean toward the turbo seal being shot. but as pointed out, do the leakdown test.

 

[Spoolin4Ever]

It was valve guides....head swap took care of it.