Valve cover breather

[JEFF]

Hey guys, Should the valve cover breather hose have pressure or vaccuum? I have vaccuum on mine ( 72' 240 ) I was under the empression that it would have a small amount of pressure out. The hose that connects the block to the pcv on the balance tube sucks vapor from the crankcase -- is this where the vaccuum in the valve cover is from??:cross-eye

[Royce]

I have seen discussions about the breather on other lists. The valve cover breather should be attached to the air cleaner and is under vacuum. I have heard arguments that this helps draw gas vapor and other contaminant gases from the valve/cam area as well as equalizes pressures.

But that is just what I have heard, any experts out there?

Have fun!

[JEFF]

Royce - Thanks for the reply - Wouldn't the valve cover have some vaccuum on it because of the pcv port attached to the carb. balance tube??

[Royce]

The valve cover breather is attached directly to the air cleaner and yes would be under vacuum. The PCV draws vapor out of the block by vacuum.

But I don't know if a bad PCV valve allows more or less vacuum or maybe to regulate pressure at various RPM levels!?