924Board.org

jessy1984 · Joined: 09 Jun 2009 Posts: 82 Location: belgium

hi i have a 931 that has a strange problem
when i start the car after 30sec it starts to smoke a lot
after looking in to this it seems to come from the turbo there is always a bit of oil in the housing

but the engine and turbo has been completely rebuild
this only accured after the rebuild
when the engine is at tempreture the smoke is gone so it only accurs when the engine is warming up

did anyone have a problem like this with the turbo before
also checked the oil pressure this is at max when cold 6.3bar
with castrol Edge 10w60 full synthetic

Shurick · Joined: 15 May 2005 Posts: 524 Location: Russia, Moscow.

Fasteddie313 · Joined: 29 Sep 2013 Posts: 2595 Location: MI

Mine does the same and I'm quite sure its coming from the hot side of the turbo leaking a little into the exhaust when the car sits for a while. Like it burns off when the exhaust is coming up to operating temperature.

The turbo in my car is questionable at best, it is very likely a bad seal on my turbine piston rings.

My lines are clear, I washed them myself in and out, but I do not have the updated AOS breather setup.

I also suspect it may be a symptom of my car being a little over full of oil.
_________________
80 Turbo - Slightly Modified

9xx · Joined: 18 Jun 2006 Posts: 627 Location: Jarvenpaa, Finland

Rasta Monsta · Joined: 12 Jul 2006 Posts: 11733 Location: PacNW

FWIW, fresh rebuild here on engine and turbo, car never smokes. Car is an S1 with turbo drain AOS update. Crankcase breather is also connected and functioning properly.
_________________
Toofah King Bad

WeiBe (1987 924S 2.5t) - 931 S3

jason c · Joined: 13 Jan 2014 Posts: 1018 Location: Nwi

That's a lot of oil pressure, is this the same oil you were using before the rebuild?
Has the temperature outside changed much since the rebuild?
Does your car have the head vent update?

jessy1984 · Joined: 09 Jun 2009 Posts: 82 Location: belgium

all lines are open crank ventilation is working and dous not have to much pressure for what i can see.
also did a compression test and leakdown test both are good and engine runs verry good also.
oilpressure with my row924 was the same
i did just change to the 10w60 from castrol after rebuild why cous it is full synthetic and with a rebuild clean engine a good thing
also this oil can resist the high temp from the turbo.
outside temp isnt the problem its not that cold and the car sits in the garage.
also its an S2 so it has the vent update on the head

jason c · Joined: 13 Jan 2014 Posts: 1018 Location: Nwi

931 spec= Oil pressure (at 5000 rpm)Up to approximately 6 bar (85 psi) at 80° to 100°C (176° to 212°F)
924 spec= System oil pressure (at 2,000 RPM)5 to 7 bar (71 to 100 psi) at 80° to 100°C (176° to 212°F)

You have 6.3bar (93 psi) so yes, its high.
I would try changing to a lighter weight oil & see if it helps.