What does the PCV valve really do? Seeing that the road draft tube is always pulling fumes out couldnt you just have a tube coming out the back of the valley pan that has vacuum hooked to it with baffling so it wont pull oil also? I ask because I got a valley pan with a PCV valve on the back with the original baffling but as you can see in the picture there is no "valve" in the middle but just a open tube. Thanks



Sebastian



Sorry no pic but the site keeps on saying i have exceeded my limit but I have never uploaded a pic and it is a phone pic so it is not a huge file so I dont get it.

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

The Thunderbirds had the road draft tube down the back of the motor because of low road clearance.You can use that pan with a grommet and PCV valve plugged into the intake manifold as close to centre as possible or plugged into the carb if there is a provision for it like the 390 Holley does.The PCV allows crankcase fumes to be reburned instead of allowing unburned fuel and other fumes to escape to the atmosphere.The most noticeable improvement I found was that the garage does not smell of gas and oil with the PCV setup.That pan you have is hard to find.You might consider doing a PCV setup on yours.

  

Yeah, I got the pan with the PCV update in mind but like I said the "valve" is just a open tube on the rear of the valley pan. It has the original tubing from when it was used on the 60 truck already to go but with no guts inside it I wonder what the actual valve portion does seeing that the draft tube was always open, why do I need a valve that will open and shut when hooking it up to the plate under my carb?



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

If you want to see the picture I was able to post it on the FTE site with the same question. Here it is

http://www.ford-trucks.com/forums/1177787-pcv-issue.html





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

The open tube just lets fumes pass through and out on their own. The PCV, positive crankcase ventilation, uses intake manifold vacum to pull the fumes out of the block and valley pan and send them through the engine. Its the positive part that makes them worth the effort.

I had a mechanic show me a graphic demonstration on a Pinto 4cylinder car. It sounded good, idled fine, and drove without smoke. He pulled the PCV and blocked it and the car smoked BAD. Lots of blue oil smoke at idle. Quite impressive. 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

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

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

[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

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

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

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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)