I think the valve is more of a regulator type device -- not merely a
check valve. The idea is to keep a SLIGHT partial vac. in the
crankcase. The spring - diaphram arrangement regulates it. I
definitly helps keep the oil on the inside from what I've seen of
people who remove them. Even just venting the crankcase might not be
enough... the partial vacum is the ticket. Remember the crankcse
should be a closed system --- probably only the blow-by from the
rings gets by - charge that should have gotton burned and didn't.
Since the crankcase is not open to the atmosphere, it's not a leak.
(Mine don't run right when the oil cap is opened.) When the system is
working properly there shouldn't be any power loss at all...that
unburned fuel vapor probably condenses in a plain old vented
crankcase...leading to oil dilution. From the published HP figures, I
think this is one emmissions device that doesn't cost any HP. HP
actually went up fron 100 to 104 on the PCV engines. Not because of
the PCV... but not in spite of it either....
Princeton University Press
Tel:609 258 4900
Fax:609 258 6305