[KULTULZ]

I don't remember a valve. They simply blocked off the road draft tube and routed a hose from the oil filler cap to the air cleaner. That way the fumes got sucked back in the carburetor and burned.

It had to have a valve -

A second function of the PCV valve is to act as a flame arrester and to prevent positive pressure from the intake system from entering the crankcase.

This can happen on turbocharged engines or when a backfire takes place, and the positive pressure could damage the crankcase seals and gaskets.

The PCV valve therefore closes when positive pressure is present, to prevent it from reaching the crankcase.

SOURCE - https://en.wikipedia.org/wiki/Crankc...ilation_system

Without the valve which is also a controlled flow metering device, the engine would run too lean if you could get it to start.