pcv valve

[Howard H.]

Did 64 300 hp L75 engines come equipped with a PVC valve? I've found references to FI cars coming with a CV590 valve but nothing specific to other engines. Thanks;
Howard Hiller (46797)

[Harry S.]

Re: pcv valve

Did 64 300 hp L75 engines come equipped with a PVC valve? I've found references to FI cars coming with a CV590 valve but nothing specific to other engines. Thanks;
Howard Hiller (46797)

As far as I know it was used on 63's and 64's. I have one my 63 250 and 300 hp engines.

Per Joe Lucia.....

I'm not sure just what applications used the CV-590 during the 1963-64 model years. I have conflicting information. I believe that some applications during this period used a "calibrated orifice" instead of a valve.

In any event, as far as the CV-590 goes, it was used for some applications during the 63-64 period. The CV-590, GM #5649689, was discontinued in January, 1966 and replaced by the CV-590C, GM #6421934. I have forgotten just what the "C" suffix denotes but whatever it denotes, the CV-590C can be used in place of the CV-590 for any application originally using the latter. The CV-590 is of mostly "machined steel" construction while the CV-590C is mostly of stamped steel construction.

The CV-590C is now discontinued although I expect that will be plentiful on eBay and elsewhere. However, there is currently available from GM and AC Delco a replacement for this valve. It's AC Delco #214-2295 and also known as GM #19250958.

[Howard H.]

Re: pcv valve

Thanks Harry
I don't see evidence of either on my engine. I just looked at a 64 passenger car owners guide and it shows a picture of the orifice type ventilation. It shows the pvc hose coming from the back of the engine instead of the oil fill tube on my engine and is attached to the brass fitting at the back of the carburetor. I guess my question should have been should my 64 300 hp engine have one or the other?
Howard

[Ed S.]

Re: pcv valve

Just curious, and want to learn something new today (running out of time), if the 250 and 300 HP 64s came with a PCV valve, why not on the L76 engines too?

[Duke W.]

Re: pcv valve

I don't think any '64 engine PCV systems had valves, except maybe early FI engines that had 375R FI units and '63 FI distributors.

The answers except maybe those early '64 FI engines are in the 1964 Corvette Shop Manual Supplement and AIM.

Duke

[Ed S.]

Re: pcv valve

Ah! I get it - you said, "PVC systems" - the engines do have built in breathing "system" it just doesn't include one of those small aluminum "valves" that rattles around when you shake it. The crank case plumbing system relieves the crank case pressure - it goes back into the carb Thanks! I KNEW THAT!!