The engine in my PV was sourced from a '75 240 that was originally equipped with the mechanical (CIS?) injection. Naturally the intake had already been removed by the time I got it, but it made no difference to me because I had always intended to run the twin SUs that came with the PVs's B-18. But somewhere along the road a later intake/exhaust manifold had been substituted onto the B-18; the all-in-one, secondary butterfly equipped, dual exhaust ported manifold, which I believe came standard on early B-20 powered 140s.

I studied a Hanes manual for crankcase ventilation hook-up, and it showed 2 configurations for the B-18 and the B-20 and the flows were opposite each other. The B-18 draws in fresh air through the air filter, through the valve cover cap, then out the engine at the crankcase breather, through a PCV-type valve, then finally into the engine at the intake. The B-20 system attaches the crankcase breather to the air filter and the flow goes into the intake fitting from the valve cover cap. The B-20 system relies on a fixed orifice inside the intake manifold hose bib fitting instead of a PCV valve to limit the airflow. Personally I prefer the B-20 hook-up because there is no valve to foul. But my manifold has a hose bib that is wide open, perhaps taken from the B-18 manifold.

I'd like to ask if anyone would know what the size of the orifice is supposed to be in the B-20 manifold hose bib so I can make my own orifice.

Appreciate all the help,

Joe in St Louis