67 PCV Valve

[Jeff]

Re: 67 PCV Valve

The 726Cs regulary turn up on eBay, sometimes for as little as a buck or 2 apiece. I just saw an NOS PCV around here a week or two ago while I was looking for something else. I think it was a 726 but may have been a 736. My recollection is that this one is the two piece stamping, whereas the originals were a one piece machined part but I'm sure it is functional. Either way, anyone who wants it can have it if they are willing to wait until I run across it again.

JP

[Brandon K.]

Replacement valve?

Will a parts store replacement valve work as well?

I'm currently doing a frame off on my 67 327/350 hp, and now I'm wondering if I need to find a NOS valve, or if the one from Autozone will work just as well....

Any advice? I might need you guys to keep your eyes open for one of those NOS valves for me. Thanks again.

Brandon

[Dave - NCRS#24235]

Re: Replacement valve?

The Autozone valve works fine in my 66 with a 69 mule motor. The original 66 BB that's in a bag in my garage has an NOS valve (for show). - Dave Wrzesinski

[Pete Lindahl]

Re: 67 PCV Valve

Nick - Wow, this PCV thing has gone critical. Great arm chair auto mechanic suggestions, but let's get the problem accurately diagnosed first. Althought I hate to suggest to people to just change parts and see if that fixes a problem, in this case I suggest you get a brand "X" replacement for the AC CV-726C (can't cost too much) and see if that eliminates the noise problem. If so, then deal with finding an NOS one and if it doesn't you'll have other things to deal with. Pete

[Joe L.]

Re: Replacement valve?

Brandon-----

I didn't realize that there was an aftermarket replacement for the CV-726C. As far as I know, the last production application for this valve was in 1967. In any event, apparently they are available. In my opinion, they ought to work equally as well as the AC-sourced valve. I'm sure that they're manufactured to the same technical specifications.

[Dale Pearman]

Word of Caution

These valves are GM named, "Metering Valves". Each is designed to REGULATE, usually in linear fashion, the QUANTITY of passed gas (no humor intended) as a function of vacuum (pressure differential). A simple cam change, with different profiles will result in different vacuum characteristics requiring a respecification of PCV characteristics. Also engine wear figures into the equation. Seat-of-the-pants experimentation with available valves may be the answer.

Varooom

[Gene M.]

Re:L79 cam spec

Dale, lift is .447 and lobe spacing is 114 degrees, yes you were very close!

[Dale Pearman]

Re:L79 cam spec

I'm too lazy to look up specs and too old to remember accurately. Sometimes I even have to ask directions to get home! Thanks for setting the record straight.

Dale.

[Iron Duke NCRS #22045]

A word or caution!

In my experience the aftermarket parts catalogs are as riddled with errors as the GMPD catalogs, and, in fact, in many cases just repeat them. If the aftermarket catalog calls for a 23xyz valve, check the cross reference catalog and verify that it does, indeed, cross reference to the OEM GMPD or AC Delco part number. If your parts store doesn't have the cross reference data, contact the manufacturer of the valve. Most have customer assistance numbers listed in the catalog.

Duke

[Nick Vigorito]

Re: 67 PCV Valve

Pete,

I'm really quite amazed at the number of responses that I have gotten to what I thought was a very minor issue. Even with this ticking PCV valve my 327/350 is VERY strong from the bottom to the top of the RPM range. Maybe it could be even stronger? Thanks to everyone for their input. Changing to a replacement before bothering to NOS to see if that fixes the problem is a great idea. Thanks!

Nick