Crankcase breather question

Im still having a hard time understanding the transitional value for the pcv vacuum.
The hole you see at the bottom is not the orifice, but rather the back-fire valve to prevent a cc explosion.
The actual orifice is at the other end. The valve is a tapered pintle affair, so depending on where it is at any one time, the tapered section controls the flow between minimum and maximum.


pcv-operation.gif