# Pcv question



## Unactive1 (Dec 10, 2019)

I have the original pcv setup "valley pan to intake". Had a baffled grommet in passenger valve cover. I am about to install new edelbrock 4457 tall baffled covers and was wanting to know, which valve cover breather style i should use. With or without the pcv ? If i use the one with pcv it connects to air cleaner correct? Any help would be much appreciated.


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## Lemans guy (Oct 14, 2014)

You always want a PCV vale, a breather alone does not create a negative pressure in the crankcase necessary to suck out the vapors thru the intake. The blowby vapors, condensation and crud all work to slowly destroy your engine. Although Positive crankcase ventilation is good for emissions crankcase ventilation was designed decades before emissions regulations.

The best recommendation I would give is to get an ME Wagner dual flow PCV which you tune yourself with a vacumn gauge to your engine. It will pull a vacumn on your crankcase 99% of the time. Go to the ME Wagner site and read it watch the video read the studies call and talk to them. One of the best things you can do to your engine.

old Hot Rod wives tales with “Just a breather” on the valve cover or valley pan does not pull a vacumn ever to evacuate the fumes, blow-by and condensation. Old Road draft tubes did not operate at all at idle.

whatever you do use a PCV.


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## Unactive1 (Dec 10, 2019)

Thank you lemans guy. So what you're saying is, just the breather in cover isnt enough and doesn't ventilate the fumes out. So putting breather with pcv in cover and plumming it to air filter (like it was hooked up from factory) i dont think it had pcv there originally. Was just a metal tube from valve cover to air filter with what looked like cotton filter element inside air filter. That setup would be correct right? Will have two pcvs (1) valley to intake
(2) valve cover to air filter

Holding off on a summit order until i know im getting the setup right the first time round.


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## Montreux (Mar 8, 2009)

Not sure what year your engine is, but I’ll start with ‘67 because that’s what I’m most familiar with. The PCV valve plugs into a grommet in the valley pan behind the carburetor. The hose comes forward to an “F” fitting, and two hoses go to the intake manifold ( factory dual plane manifold). Passenger side VC has a rubber plug. Driver’s side has a twist-in breather.
I think on California-emissions “closed” PCV systems, the breather gets replaced with a non-vented twist-in oil filler cap. The rubber plug gets replaced with a grommet, and a metal breather tube goes to the air cleaner.

So, PCV valve draws crankcase fumes into the engine to be burned, and makeup air comes in thru the breather or air cleaner.

On later cars, the PCV moved to the front of the valley pan, and they changed to a single connection to the manifold or carburetor. All cars went to a closed system so that makeup air was drawn from the air cleaner housing (usually with a filter).

Sounds like you have a system with the vent tube from the valve cover to the air cleaner. I suppose you can replace this with a push-on or twist-in breather on your new valve covers.

Either way, keep the PCV valve and the vacuum connection to the intake manifold or carburetor.

While you’re in there, replace or clean the PCV valve.


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## Unactive1 (Dec 10, 2019)

Montreux. It is a 72 block with 70 model ram air III heads #13. It was originally a 72 luxury lemans 350 2bbl. With the tube from valve cover to air filter on carb. Mainly wanting to know which valve cover breather to get. With or without the nipple to connect plumming back to air cleaner.

Picture is breather i am thinking of getting. The nipple on it will connect to tube for my cold air setup correct?


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## Montreux (Mar 8, 2009)

Rad!

If you use the 4407, it needs to be piped to filtered air. If you use the 4213, it breathes through the extra ring of holes drilled on the underside, and filters the air inside the housing.

If you already have a place to connect the 4407, it will be the cleaner install. All engines have some blow-by; older, tired motors have more blow-by. If you have a lot of blow-by, the 4213 will eventually saturate with oil and drip onto the valvecover. Looks like you can disassemble and clean either breather.


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## Montreux (Mar 8, 2009)

Hold the phone!!

I just went to the Edelbrock website. The 4213 is a breather. The 4407 is a PCV valve that LOOKS like a breather!

If you still have a PCV valve plugged into the valley pan and connected to manifold vacuum, you do not need the 4407. All you need is a breather (4213).

If you do not have a PCV valve, then you need both; 4407 plumbed to manifold vacuum to suck out the bad air, and 4213 to let in the good air.


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## Unactive1 (Dec 10, 2019)

This should be the correct one then. This is the old breather top off the 2bbl carb setup. The filter is attached to side of breather. This procomp breather would filter air coming through filter and send the good air back into carb. All i would have to do is plum it back to my cold air tube. Im not drilling a hole in the plenum cost too much


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## Lemans guy (Oct 14, 2014)

So the two PCV systems are one is allowing fresh air into the crankcase thru the air filter and one is just allowing fresh air in thru a valve cover breather. Montreal described it correctly.

they are both closed systems, as the PCV using intake manifold vacumn sucks air from the crankcase “Positively” and resends it to the intake where it is reburned. But fresh air must come in to “Ventilate” the crankcase and it should be filtered non dirty air. The air cleaner can do this. Or a breather or two that has a good filter. The old style “Oil cap” filters we all used, with the wire mesh Brillo inside and a ring of holes on the bottom. Not a very good filter for air, but OK. Newer filters are much better, I use K&N air breather on the valve cover.

The pipe to the air cleaner is not required for good operation but will filter the air better than the Oil Cap. Some guys want the original look, some states may require it stay original.

You can even use two PCV and one or two breathers, I have done both. But you must have at least one PCV and one breather. You need to have the crankcase fumes sucked out and the fresh filtered air entering the crankcase.

best solution is an ME Wagner Dual flow PCV in a baffled valley pan or valve cover and a good filtered breather, or even two breathers,...your engine will love you and you can feel the difference!


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## Unactive1 (Dec 10, 2019)

Well the covers fit nicely. No big issues installing besides unplugging some plug wires. Got the 90° elbow installed on cold air tube for valve cover breather hose. Thanks all for the help with this.


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## GIgtoGuy (Jun 24, 2021)

Hey Lemansguy! how would this set up work…70 gto 461 has the crankcase breather tube from passnenger valve cover to oem air filter housing and the oem style pcv from valley pan to front of the carb is there. I got the me wagner dual flow But it won’t fit in valley pan pcv (not enough clearance) so should I remove the air breather on the drivers side valve cover and tee it into the valley pan hose? Would that be too much? I have rear main and valley pan oil seepage? TIA


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## Lemans guy (Oct 14, 2014)

No don’t tee it. You need a separate breather and separate PCV.


First did you buy from Me Wagner the Pontiac Adapter? It elevates the PCV so it clears and has easy access it is on their web site. That would be the


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## GIgtoGuy (Jun 24, 2021)

i did try the Pontiac adaptor. The intake I have does not have enough room for the Wagner adapter. So should I use the Wagner pcv on one valve cover and a breather on the other and take off the crankcase tube to the air cleaner and just leave the oem pcv in the valley pan? I could post pics if it’s hard to follow …What would you recommend


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## Lemans guy (Oct 14, 2014)

Yes I would put the Wagner in one “baffled” valve cover and a breather in the other which does not have to be baffled. This is how I run mine.

in the valley pan I just used the Wagner Pontiac adapter with a 45 degree elbow and a screw on cap. I just use it for an oil fill. Goes right in the crankcase. The air breather connection you can just plug. By the way I use a small K&N valve cover air breather, has great flow and cleanable


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## GIgtoGuy (Jun 24, 2021)

Sounds great I’ll Try it that way. So you believe the Wagner dual flow will pull more pressure than the OEM crank case breather tube into the air filter? I would think that the crank case breather tube would work better under wide-open throttle as where the wagner would not because there’s no vacuum at wide-open throttle?


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## geeteeohguy (Feb 2, 2008)

What Montreaux said you can take to the bank. The PCV runs from valley pan grommet to F or Y fitting to both planes of the intake. As for VC breathers, you can vent to atmosphere or run a tube to the air cleaner assembly. You for sure want to run the PCV as it keeps the crankcase scavenged, preventing sludge build up and oil leaks.


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## Lemans guy (Oct 14, 2014)

Neither one will pull any vacumn at WOT….because as you said there is no vacumn then.

yes the Wagner will pull 1 hg to 3hg 99% of the time…the standard PCV maybe 30%…..the Wagner is just way more efficient, because it has those 2 circuits tuned to your engine for idle and cruise… the fresh air intake thru a breather on the valve cover or thru carb is that a fresh air intake….the air cleaner filters it…or a good valve cover breather like the K&N will filter it too…but the main thing is that strong vac inside to evacuate it ..”Positivly”….sucks it out


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## Lemans guy (Oct 14, 2014)

PS I do agree that the air intake thru the carb will have a little more velocity at WOT than a breather on the valve cover, but it is fresh air in with no outlet at WOT…so it does not really help you any. I do see your assessment and agree you are right that it will pull some more air…

but WOTis usually short duration and with the Wagner once you are off ityou are back to an almost constant crankcase evac which is good for your engine…..


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## GIgtoGuy (Jun 24, 2021)

That does make sense. Thank you thank you for educating me. I will remove the crank case breather tube and install the Wagner PCV in its place and just have the K&N breather on the other valve cover. Hopefully this will ease my oil leaking problems.


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## Lemans guy (Oct 14, 2014)

If you do this and just use the valley pan for oil fill, I used the Wagner PCV adapter and then
from summit..

A Russel. 663090 fitting 45 degree pipe to 5/8
Summit 220240B -12 AN Flare cap black…

suppose some other fittings could fit too…


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