Originally Posted by jtranger
I bought my '65 with an aftermarket carb and there is a Pcv valve and grommet where the crankcase vent tube would go. The hose with the pcv then goes to the inlet of the carb pcv connection. It seems like the carb inlet pcv is sucking in some oil into the carb. Is this pcv connection to the vent tube area ok? Thanks Larry
The current direction of flow is directly opposite of what it should be!
Are you using the correct, stock air cleaner? The filtered, intake air to the crankcase runs from the air cleaner housing (equipped with steel screen flame arrestor), to the rear of the block (where your PCV valve is now located). Inside the lifer valley, and upstream of the air inlet, is the vapor separator cannister (which sometimes is omitted by dimwitted engine builders). Crankcase vapors are sucked into the carburetor through a special 90 degree fitting on the left side of the carburetor (pictured by poster, above). This fitting has a .090" orifice, which served as the PCV valve for 1964-65. A hose runs from this fitting, to the oil fill tube.
Flow during most driving conditions (low to moderate manifold vacuum) travels from the air cleaner, into the crankcase, out the crankcase thru the oil fill tube, into the carb orifice,into the intake manifold, where its burned. During transient periods of high manifold vacuum (i.e closed throttle operation), this flow reverses.
Your engine can be upgraded to use a PCV valve in place of the .090" orifice for better operation, but if you do so, you must use a PCV closely matched to the correct orifice size. I plan on doing this to my 327/365, but have not researched the issue, yet, so cannot offer any advice on proper PCV to use. I would strongly suggest that you use the orifice fitting (widely available, as mentioned) before experimenting with PCV valves.