Chris & Bill Strickland lechevrier at earthlink.net
Mon Dec 13 20:21:41 EST 2010

> I installed a PCV valve and the leaks stopped..... 

I am convinced that the post draft tube Corvair design is NOT a  
positive crankcase ventilation system.  Yes, it has a PCV valve, but to 
have positive ventilation, one needs a fresh air inlet to the crankcase, 
which the Corvair does not have.

It takes pressure in the crankcase to overcome manifold tube suction of 
free air from the air cleaner -- this pressure, although eventually 
relieved somewhat through the PCV system, whether valve or orifice, does 
not help keep our Corvairs from "marking their territory". 

Beyond some point from "factory new", and I'm sure nearly every Corvair 
is well beyond that point, the PCV system, especially the orifice, 
merely works as a diverter to recycle crankcase vapors to the air cleaner.

I believe a proper crankcase ventilation system would alleviate many of 
our leaky seal woes (see nearly any GM Vee engine for reference -- fresh 
air into this valve cover, PVC suction on the other one).

Bill Strickland

More information about the VirtualVairs mailing list