I have a boosted LS/vtec that has been smoking under boost and deceleration. So after a couple of compression test and it seems oaky, I decide to change the valve stem seals.

Today I went out for a run and the smoke is still there.

Ive been reading about the leakdown test and how it works. I dont have a leakdown test gauge yet but I decided to run pressure through each pistons at TDC and see if I can see anything obvious.

Well piston 1 is leaking air out of my catch can breather. Leaking pretty bad too compared to the rest of the other piston.

What does leaking alot of air out of the crank case breather mean?

Please help.. I will be getting a real leakdown tester as soon I find one and retest it.

Also there is oil on all 4 pistons.

Thanks

 

Air out the breather would indicate bad compression rings. A leakdown or compression test won't tell you anything about the oil control rings. However, it sound like you could possibly have bad rings which should have shown up on the compression test. Did you do both wet and dry compression tests?

 

I didnt do a wet one because when I look down at the pistons all of them look wet. Looks like oil so I didnt do any wet compression test. Ill do a dry and wet compression test again today and update.

The car doesnt smoke at idle just at boost and hard WOT and also deceleration, but there is a little smoke coming out of the valve breather and my crankcase oil catch can at idle.

Wouldnt a bad piston ring #1 cause the car to smoke at idle? or does it take several bad rings to smoke at idle?

How about the wet pistons on all four? is that normal?