On Fri, 29 Sep 1995, F. van Dalen wrote:
> I spent part of this summer's vacation in France, trying to keep up with
> with a friend in a Westfield Seven. One day we stood bent over my B's engine
> compartment admiring a knocking sound from what is presumably a worn valve
> guide, when on an impulse my friend lifted the oil filler cap to improve the
> sound quality. What happened then is unspectacular but I just can't figure it
> out: we got a very noticable increase in RPM. How the heck is that possible?
> I had one carburettor running too rich at the time, but apart from the one
>valve
> the engine is performing very nicely. I don't have compression readings, but
> considering the car easily reaches 90 mph I assume compression is OK.
>
> I don't think there is an actual problem here, but I'm just dying to know why
> lifting the cap increases RPM. Any comments welcome,
>
> Frank
>
>
Well Frank you just succesfuly tested your breather control valve (PCV
valve) and it passed. I haven't really though it out but probably
removing the cap changes the crankcase pressure and cuts the valve out
meaning only fresh air is being used. Anyway removing the oil filler cap
is the recommended way to test your PCV valve. (I'd take it from your
post that your car has an 18GA,18GB or 18GD engine ie pre 69, if not then
all bets are off)
Gary
MasterClk__| |_| |_| |_| |_| |_| |_| |_| |_| |_| |_| |_| |_| |_| |_| |_|
__:___:___:___:___:___:___:___:___:___:___:___:___:___:___:___:
Character__|20_|47_|61_|72_|79_|20_|42_|75_|72_|72_|65_|6C_|6C_|20_|20_|
:_______________: : :
FirstName______| |___:___________________________:________
: __________________________:
Surname __________________________| |________
Electronic Signature: Gary R. Burrell P.Eng. (burrelgr@tuns.ca)
Try my new home page (http://www.tuns.ca/~burrelgr)
|