Chuck.  While your aluminum valley cover had a threaded hole at the back of it for a screw in style of PCV valve, it has a plug in the hole.  I did not find a PCV valve in your pile of parts.  The flat bowl Holley carb you provided did have a hose on it though but no PCV valve sticking on its end.  Your engine so far has been run without a PCV valve.   That’s simply due to the engine being run with the roots blower and not the McCulloch unit.  At this point, it’s been more expedient from a testing standpoint to not have PCV in place.  When I get the engine back on the dyno, I’ll fit a PCV valve to it so it’s tuned with the valve in place.

Lorena, Texas (South of Waco)

Ted,

When you dyno'd my new engine did you use my valley cover and the PCV valve thats in it? I bought that one on size to fit the hole and not by engine size. It could be too big and possibly be part of my erratic idle problems? Chuck

Y's guys rule!
Looking for McCullouch VS57 brackets and parts. Also looking for 28 Chrysler series 72 parts. And early Hemi parts.

MoonShadow, 292 w/McCulloch, 28 Chrysler Roadster, 354 Hemi)
Manchester, New Hampshire

Thanks Ted, that is awesome info.

1958 F100 292

"Nothing is particularly hard if you divide it into small jobs."

"Chop your own wood, and it will warm you twice."

-Henry Ford

Sebastian. Your are correct in that a PCV valve is a controlled vacuum leak. It’s metered so that the excess pressure from the crankcase can be reentered into the engine and combusted without leaning out the engine. Most new universal carbs are calibrated to include the PCV valve air flow as part of the idle circuit fuel mixture which means not using the PCV valve on a carburetor designed to use one will typically have a rich idle and possibly to the point that the plugs have difficulty in staying clean at low rpms. Whereas a road draft tube only works when the vehicle is moving, the PCV valve works as long as manifold vacuum is present. If you’re looking for specific flowrates, here’s the link and information from a past discussion..

http://forums.y-blocksforever.com/Topic22760-3-1.aspx

.

Lorena, Texas (South of Waco)

Ted, I had done the search but did not see anything on what I was asking. I know I wanted to do a PCV and looked at what I needed and how to install it but I wanted to know a little more specifics of the actual valve and what I think I have found is that it creates the right amount of vacuum so as not to have a complete "leak" in the system. This tells me I can not run the gutless valve that came on the valley pan that I will be using. In all of the post you have there none has this information and thus my new post on a old subject. Thanks all



Sebastian

1958 F100 292

"Nothing is particularly hard if you divide it into small jobs."

"Chop your own wood, and it will warm you twice."

-Henry Ford

Here’s a partial list of discussions found on this site regarding PCV valves. Using the search function will bring up more.

.

Blocking off the road draft tube

Crankcase evacuation

Finned valley pan and PCV valve installation

Installation of PCV valve into the top of the block

Installation of PCV valve at top and rear of block 2

Modifying valve covers for PCV valve installation

Valley pan PCV valve installation

Valve cover baffle for PCV valve

Why a PCV valve or system?

Lorena, Texas (South of Waco)

I used the valley pan for PCV. I removed the hose adapter and threaded boss the screw goes into. Put a universal pcv grommet in the hole and used a pcv valve with a right angle fitting on it. hooked that to the back of my carb.

Kenny  Onalaska, Texas

[quote]cbass139 (7/24/2012)

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What does the PCV valve really do?



Aside from environmental concerns, it extends your oil life big-time. I believe the PCV spring also balances/limits crankcase vacuum and pressure.

6 VOLTS/POS. GRD. NW INDIANA

Thanks guys, I went and got a PCV for a 302 which is pretty close to my 292. All the info was very helpful. Will do the work this week and see how it turns out.

1958 F100 292

"Nothing is particularly hard if you divide it into small jobs."

"Chop your own wood, and it will warm you twice."

-Henry Ford

Cbass - The PCV for the application you are using had its valve screwed into the front of the intake manifold. It goes into a port that provided manifold source vacuum to P. brakes wipers - something - the port also incorporated a drilled hole into both manifold plenums. From the valve, a tube passed back to a baffled elbow on the valley cover. 

I have tried out the same valve (modified a bit) stuck right into the elbow at the valley cover - then plumbed to a carb port. It pulled way too much air due to the free flow and made my idle uncontrollable until I put an orfice in the line. As you can see in the picture - the orignal port was pretty restricted.

 
 Steve Metzger       Tucson, Arizona