Re: [Amc-list] Idle speed and PCV / Oil Filler Cap Questions ....

[Wrambler242@xxxxxxxxxxx]

The pcv valve in and of itself is not "necesary". It only prevents backfires from presurizing the crancase and or I guess in an extreme case igniting the fumes? The pcv is more of  a designed meter or restriction to control the amount of Vacuum leakage, especially in a "vented" engine.
   The 4.0l's for years just used a restricted vacuum line run to the valve cover.
 Your system sounds like it would not work very well to inhale the fumes as IIRC that cap is also vented therefor half or more of your vacuum is just pulling in  outside air? If the cap is sealed you are simply running the system backwards and it will do no real harm that I can think of as-is, maybe a little sludge buildup in the vacuum tube?
   You could reinstall a pcv in that line or another form a restriction to lessen the amount of leakage. When you start seeing oil vapor on the breather you can assume that it is no longer pulling enough vapor from the crankcase.
   Or, I'm completely wrong and I'm sure someone will point it out!

--
Mark Price
Morgantown, WV
1969 AMC Rambler, 4.0L, EFI, T-5
" I was different before people dared to be different" 

 -------------- Original message ----------------------
From: greg_taylor@xxxxxxxxxxxxxx
> Hi all,
> I have the oil filler cap vent hooked directly to the PCV port on my 
> Holley carb (360-V8 in '89 GW) and a long tube with a vent filter 
> stuck into the stock PCV grommet at the back of the intake.  I've run the 
> Jeep like this for a long time (no PCV valve).  However, I 
> decided to squeeze off the hose from the oil fill cap to the PCV port on 
> the carb.  When I did this, the idle dropped by about 200-300 RPM 
> (it was idling too high).
> 
> Does anyone know how critical the PCV valve is on the Jeep?
> 
> Also, I'm considering that originally, the oil fill cap had "some vacuum" 
> to it, since it hooked to the air cleaner, and that the PCV 
> valve side also had "more vacuum" to it ... I'm thinking that perhaps I 
> should modify my current setup, as it would appear that I have 
> created a "vacuum leak" since I'm sucking air through the engine now.
> 
> Any thoughts on this setup, folks?  Thanks for the input.
> 
> Sincerely,
> Greg Taylor :)  <><
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