Lots of smoke on over-run but clean on boost.
 

As per the thread title really... I've just been for a blat after the car's been stood a few weeks. After I got everything up to temperature I gave it some berries, clean as a whistle, all good.

Then as the vacuum builds, and I'm coasting the oil cloud starts behind me. By the time I'm stationary it's 100% solid and laying it out of the exhausts at idle. In the time it takes me to hop out, look for leaks, check where it's coming from, it clears up.

Then another blat, all fine, until I stop thrashing and coast down.... SMOKE SCREEN then clear after a minute. At idle, back home, it doesn't smoke.

Any ideas? Chinese turbo seals? Valve stem seals? Piston rings? Throw me a bone...

My car would do that-New piston rings were answer.

Either that or intake valve guides leaking under high vac

Mine would still smoke in boost if you got in the throttle hard and looked back. but it wouldn't really show up until in vacuum and between shifts.

I replaced my valve seals to no avail. Had perfect compression, but it seems the oil rings were bad, everything looked fine when it was pulled. Swaped in at a low mileage (70k) block and all was well again.

I'm not seeing anything on boost, or even in shifting, it's got to be in vacuum for a while for the smoke to start. But, boy, does it smoke when you get it started!

hows the pcv condition? might be similar to what curly was seeing.

Sorry to be dumb, but is the PCV the non-return valve on the top of the cam covers? With a pipe going out over the exhausts near the front? I have that pipe plumbed into a small catch tank instead of into the air intake.

how full is your catch can?

Nothing but surface slime in the bottle, not even enough to pool. :(

HAHA! THE CHINACHARGER LIVES!

Thanks for the direction re: PCV.

PCV pipe was full of oil, but PCV itself functioned fine... so then I checked the intake side of the crankcase breather system, which is plumbed in to a catch tank I made...

lo-and-behold, the pipe it was blocked by a melted t-piece from turbo heats.

Just ran the breather au natural to atmosphere and the car runs clean as a whistle.

Cheers for your prompt replies and helpful direction! :)