PCV in a 239 Y F100

46yblock

46yblock

Senior Member
I'm trying to help a guy in TX who wants to put a PCV in his 239 with original intake and carb. I told him that the late model Y-block PCVs were designed for larger 292 and may result in lean front cylinders. He installed it and has indications of a lean running, hot engine. Possible fixes have been suggested, to have him experiment with an inline restrictor before the PCV, a PCV for a smaller displacement engine than 292, increase of main jet sizes. He has installed a later valley cover with the rear outlet cap.

My gut says this isnt a good match, PCV/old Holley/small engine/Loadomatic, and he should just go back to the draft tube. Other thoughts or suggestions would be appreciated.
 
I have installed the '64 Ford 292 PCV systems on three of my own vehicles and a couple for friends of mine.. It is true that the PCV should match the approximate CID of the engine it is being installed on, however, I think that the 292 valve would be close enough to the 239 CID...
We have found, i.e. myself and my tuneup guys, have found that the addition of a PCV will tend to make an engine run rich because of the introduction of the crankcase blow-by into the intake.. A problem which can be encountered with the "modern fuels", (unleaded) is that they burn lean... When I put a PCV on my 57 T-Bird 312 many years ago (1984) we re-jeted the Holly carb to allow for the crankcase fumes... Recently the car was running very poorly.. All of the normal tuneup tricks were tried, to no avail.. Finally took the car to the tuneup shop.. Increasing the jet size in the carb solved the problem... I just had to have the same thing done to the Holly 4 barrel in my 460 Ford powered ski boat... The engine would not accelerate under full throttle...
 
Typically, the introduction of a PCV on any engine/carb combo will lean it out due to the additional air that enters the intake after the carburetor. It is common to have to go up two jet sizes to compensate for the additional fuel-less air ingestion. As for the size of the engine becoming a factor in all of this, go to the parts counter and ask for one for a small V8 such as a 260 Ford or 239 Studebaker. You may have to go through a few to find one that has the proper form amd fit. I have really never had an issue with engine size.

If you are burning oil and this causes the plugs to show oil deposits, go up 1 or 2 heat ranges on the plugs. For example, if you are running Autolite #45's, go to #46's. If you don't have excessive blow-by as you are running, that will likely not be an issue either.

Above all, have fun.
 
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