[s-cars] Crank Case Pressure and Turbo Smoke?

[Djdawson2 at aol.com]

In a message dated 2/22/2005 6:32:27 PM Mountain Standard Time, 
strangconst at rogers.com writes:

> I have a diagram from alldata that shows the valve, a check valve and the 
> airflow routing thru the valve cover.
> During idle the air is routed to the VC and thru it, as it appears that it 
> has a pipe inside it. During partial load the pressure control valve allows 
> the engine to pull the crankcase air into it. At no point does it so the 
> crankcase being pressurized by the turbo inlet.
> 

That's entirely correct.  However, a big turbo, with a large bypass volume 
"could" send pressure back through the VC towards the crankcase.

Put it this way... when I first installed my GT30 etc... I had huge smoke at 
every deceleration, and every shift.  Installing a PVC in line on the hose 
that goes from the VC to the turbo/MAF hose completely solved the problem.  My 
assumption here was that bypass air was pressurizing the crankcase, which causes 
smoke.
Dave