Is my Pcv valve correct?

[Vinny]

I just tried to install the correct pcv for my 66 327/300 in place of a threaded valve with no markings. The new valve is a 726c ac valve. the nipple pipe side on the new valve is open when the vacuum is applied(motor running, while the old valve closes with the motor running. I'm wondering if my system was even working with the old valve even though the motor seemed to run fine. the motor runs flat now with the new valve installed and the idle is about 200rpm higher. Is it a matter of readjusting the carb or is the new valve a problem? I put it back the way it was for now and it runs fine. thanks

 

[Hib Halverson]

If the old valve was closed when the engine was running, it had been installed "backwards". The valve is supposed to be open then the engine runs and it closes if the engine "spits back" through the intake.

A PCV valve is a "calibated" vacuum leak, so if the old valve was in backwards and the new valve is in right, the idle speed will increase and you need to readjust the idle speed and mixture.

 

[Vinny]

Thanks Hib, I definitely appreciate the info!