PCV valve location

twobjshelbys · #1 (**permalink**) 12-25-2021, 07:24 AM

Are you talking about front vs back of the same side or left vs right? If left vs right it does matter and they cannot be swapped. See the discussions about oil catch cans for the reason.

SBSerpent · #2 (**permalink**) 12-25-2021, 09:27 AM

Quote:

Originally Posted by twobjshelbys

Are you talking about front vs back of the same side or left vs right? If left vs right it does matter and they cannot be swapped. See the discussions about oil catch cans for the reason.

I'm talking left vs. right. The link you provided did not work. It just sent me to the Amsoil website.

tortuga · #3 (**permalink**) 12-25-2021, 09:37 AM

Maybe because usually the oil fill is on the drivers side? Also does the way the rotating bits throw oil, is there more oil ‘fog?’ On one side that the other? You would want the pcv on the ‘dryer’ side right?

In short i have no idea, mine is on the passenger side…

Merry Christmas 21

Steve H
Spf 1764

twobjshelbys · #4 (**permalink**) 12-25-2021, 10:57 AM

Quote:

Originally Posted by tortuga

You would want the pcv on the ‘dryer’ side right?

No. The purpose of the PCV is to recirculate oil "blow by" and other leakages back into the intake combustion side. The amounts are miniscule and contrary to the catch can propaganda do not affect octane or any other operation. Unless something is dreadfully wrong.

twobjshelbys · #5 (**permalink**) 12-25-2021, 10:55 AM

Quote:

Originally Posted by SBSerpent

I'm talking left vs. right. The link you provided did not work. It just sent me to the Amsoil website.

That link is one of the automatic links. You'll have to use forum search for "catch can". In essence, one side has positive pressure (the side with the PCV, which is why catch cans work, and the other side will be neutral or small vacuum (which is why catch cans on the other side don't get anything unless something is awfully broken). The PCV has to be on the high side.

SBSerpent · #6 (**permalink**) 12-25-2021, 11:35 AM

Quote:

Originally Posted by twobjshelbys

That link is one of the automatic links. You'll have to use forum search for "catch can". In essence, one side has positive pressure (the side with the PCV, which is why catch cans work, and the other side will be neutral or small vacuum (which is why catch cans on the other side don't get anything unless something is awfully broken). The PCV has to be on the high side.

Ah, ok. So you're saying that there is an internal pressure differential between left and right sides of the engine? My PCV is currently located on the drivers side (Ford Racing Motor 392CID w/ Holley 750)

patrickt · #7 (**permalink**) 12-25-2021, 12:00 PM

Then why did Ford put the pcv on the driver's side in the 1978 Bronco?

patrickt · #8 (**permalink**) 12-25-2021, 12:30 PM

Nice shot of the Ford Bronco V-8. Ok TWOBJ, 'splain...

twobjshelbys · #9 (**permalink**) 12-25-2021, 01:02 PM

Quote:

Originally Posted by patrickt

Nice shot of the Ford Bronco V-8. Ok TWOBJ, 'splain...

Well, from experience....

On my 427 Windsor, I did not have PCV vented into the 8-stack. Instead I had some K&N filters...

One side (the side that all others have the PCV) the filter always had some oil on it. Had to clean it "frequently" (not because I thought it was clogged but because it attracted dust). The other side was always dry as a bone. Which side - I honestly don't remember.

The purpose of the PCV is to recapture those vapors.

Why the engine works that way was explained in one of the catch can topics. I think it has to do with crank rotation direction?

By the way, how do people that have 8-stacks connect a PCV??? When I registered mine I thought CO was going to make me have one but they didn't and I didn't ask.

twobjshelbys · #10 (**permalink**) 12-25-2021, 03:31 PM

Quote:

Originally Posted by patrickt

Nice shot of the Ford Bronco V-8. Ok TWOBJ, 'splain...

A little closer examination will yield, as my old calculus professor used to say, "the answer is obvious to the casual observer". I'll disclose if you cry uncle.

Gaz64 · #11 (**permalink**) 12-29-2021, 02:51 PM

Quote:

Originally Posted by twobjshelbys

That link is one of the automatic links. You'll have to use forum search for "catch can". In essence, one side has positive pressure (the side with the PCV, which is why catch cans work, and the other side will be neutral or small vacuum (which is why catch cans on the other side don't get anything unless something is awfully broken). The PCV has to be on the high side.

That is a mechanical impossibility. Crankcase pressure is ALWAYS the same within any engine, left to right, top to bottom. Unless we have multiple crankshafts geared to together like in a square 4 or tandem twin.