Originally Posted by novaguy77
using a set of edelbrock signature series (1 hole in each) on a sbc 305, driver side pcv valve, pass. side open breather.... what causes "blow by" or smoke to exit out of the breather? Just curious....
Blow by which is the gases of combustion escaping around the piston. The PCV should be picking all of this up at idle so there should not be smoke emitting from the inlet side till the throttle is mostly open which causes a situation where these a lot of blow by into the crankcase and not much manifold vacuum to drawn it off through the PCV valve. If it's smoking a lot at idle this is either a failure of some sort in the PCV system , usually the valve but not always. The worst case situation is where the rings and or cylinder walls are worn out or damaged resulting in excessive blow by.