dfrede

I have a 1954 Oldsmobile Rocket 88. I would like to eliminate the smoke from the crank case vent tube by installing a PCV system. It sounds like this used to be a common retrofit. I think I would need to replace the vent tube with a vent hose running to the back of the air cleaner with a PCV valve installed in the line. Can anyone offer some guidance on this retrofit, such as recommending the actual PCV valve that would work with my 324 cu in, four barrel carb, non-airconditioned engine? How about the grommet size to fit the hole in the crank case? Is running the vent hose to the air cleaner the best connection point? Any help would be greatly appreciated.

joe_padavano

A PCV system needs two things. First, the PCV valve in the crankcase needs to be connected to manifold vacuum, not the air cleaner. On newer cars there is a port on the base of the carb for this. Early 60s add-on PCV systems used a spacer plate between the carb and the manifold with the port in it. Second, you need a fresh air inlet to the crankcase. On early 60s cars this was simply a breather on the valve cover or oil fill tube. Later 60s cars were required to have a closed PCV system where the air inlet tube was plumbed to the air cleaner housing.

The PCV valve doesn't need to be in the valve cover, it can be installed anyplace that is connected to the crankcase volume. The 1970-72 W-30 cars mounted the PCV valve in the intake manifold, in a web between the inlet runners. Other cars have plumbed the PCV valve to a boss on the oil fill tube. There's nothing magic about the location, it just needs to be able to access the crankcase volume above the oil fill line. On my 62 F-85, I purchased an oil fill cap with a hole and grommet in it for the PCV valve. I plumbed the vacuum side of the valve to a port on the carb (an aftermarket E-brock carb) and installed a breather on the other valve cover.