PVC breathers on valve covers

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northeastmopar

northeastmopar

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I have a breather installed on each valve cover and I have been questioned about not having a PVC valve on my 416 stroker build? Am I OK with the two breathers and no PVC valve???
 

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Maybe, Maybe not. I assume street driven?

If it was me I would have one breather and a PCV valve on the opposite side. Good to have a baffle under each as well. Good chance to get some unexpected leakage.
 
1969383S said:
Maybe, Maybe not.
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This ^. I guess you will know when you run it. It's hard to say, lots of guys get by without them.

I was talking to a guy here locally that constantly had oil leaking out of the breathers, he was on a mission to change this, that and the other. I asked him why not put a PCV on it and be done with it.

I got the deer in the headlights look, lol.
 
I run a breather and PCV on my hot 360. A PCV system really doesn't hinder performance and it helps your engine out.

No matter what you will have a little bit of blowby, and although a lot will go out the breather, not all of it will. And a by product of combustion is always water, so there will be more moisture building up than with a PCV installed.

A full system has a PCV on one side and a line that plumbs to the air cleaner on the other.
 
Im not a fan if the breather into the air cleaner ( but it may be cleaner in your garage air) as the air cleaner environment is almost always a slight vacuum. You want to draw free fresh air into the breather via the vacuum of the pcv across the lifter valley. The cotton/gauze style breathers are washeable and offer good filtration then burn it. It rids motor of acidic byproducts and water vapor, both cause sludge in oil.
 
I abstain from this discussion as my answer will only serve to cause great argument.
 
The PCV valve can also improve idle performance on vehicles normally requiring additional adjustment for idle air bypass. The are many different calibrations of PCV valves across the many makes and models out there.... I've even put a "Tee" and crossover in the header powered evacuation system and added a PVC to it with great success for street/strip action...
 
My experience..... I ran dual breathers on my 340. It always seeped oil out the breathers. The 416 I am going to build will be getting an evacuation kit to the headers. This way I can use the exhaust scavenging like a pcv system.
 
mr68gts said:
My experience..... I ran dual breathers on my 340. It always seeped oil out the breathers. The 416 I am going to build will be getting an evacuation kit to the headers. This way I can use the exhaust scavenging like a pcv system.
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but if you run a full exhaust with mufflers you create back pressure back into the engine.
 
younggun2.0 said:
but if you run a full exhaust with mufflers you create back pressure back into the engine.
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The check valves on the header draw tubes will not allow that. My 3" X-pipe system with flow masters is so efficient there is no back pressure. However not available in all states, prices may vary see store for details.....

AV12-01-C.jpg
 
Exhaust scavenger systems always run a one way valve into the header. Wouldnt want a backfire in the exhaust to blow an oil cap off!
 
RustyRatRod said:
I abstain from this discussion as my answer will only serve to cause great argument.
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I doubt it, cause you are right!

OP has an nice looking engine and I am sure he wants to keep it that way!

Mguner brings up a good point as well. Not all PCV's are the same and you may have to try a few to find one best for your application.

I would stay away from an evacuation system unless strip use with open headers is all you are going to do.
 
After running it for a few hundred miles, pull a valve cover off, and check out the film, and possibly water droplets (condensation) on the under side of the valvecover, then imagine the rest of the engine.

Do a "search" on PCV and read about all the reasons you should, and what'll happen if you don't.

cheers.
 
younggun2.0 said:
but if you run a full exhaust with mufflers you create back pressure back into the engine.
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What? Who told you that? Let's see the significant numbers, as they pertain to a PCV or EVACS .

OP
I ran two evacs on the street, but found that they work really, really, well. So well that even just one wanted to empty my oilpan through the valve cover. Even after reengineering my baffles, it still pulled enough oil under certain conditions to leave a cloud of oil behind me.I imagined a system to get around that, but,in the end I went withe PCV instead. As an aside, a PCV provides a good amount of idle-air-bypass, to help set up the T-port sync-up.I wish the carb people would engineer a nice adjustable idle-air-bypass circuit.I think it would help solve a lot of problems for newbes.
 
On my 2010 Hemi Ram I run a PVC air/oil separator, You wouldn't believe what it captures, and that would be normally going into the intake. My Cuda's 340 will get one too.
 
You should be running a PCV valve when ever you can. There is a new aftermarket PCV valve that is expensive but adjustable. I can't recall the name but I'd bet if you google PCV valves it will come up. It is the only adjustable PCV valve I know of.

If you really want to hot dog it, ise the PCV and pan evacs. That's what I'm doing on my new engine. If you stop and consider how both sytems work, it may make sense. BTW, Bill Jenkins did it years ago. Most guys now run a vaccuum pump. I hate the electric ones and I don't want to spend the money for a belt driven one.

You can use all the crankcase evacuation you can get.

If you are just going to use the PCV then have it on the opposite side of the breather. If you are going to use the PCV and pan evacs then DO NOT use a breather.
 
AJ/FormS said:
What? Who told you that? Let's see the significant numbers, as they pertain to a PCV or EVACS .

OP
I ran two evacs on the street, but found that they work really, really, well. So well that even just one wanted to empty my oilpan through the valve cover. Even after reengineering my baffles, it still pulled enough oil under certain conditions to leave a cloud of oil behind me.I imagined a system to get around that, but,in the end I went withe PCV instead. As an aside, a PCV provides a good amount of idle-air-bypass, to help set up the T-port sync-up.I wish the carb people would engineer a nice adjustable idle-air-bypass circuit.I think it would help solve a lot of problems for newbes.
Click to expand...

Some of the old AFBs from 60s Pontiacs and Chevys actually had an adjustable bypass... The big screw in the middle.
corp-1003-01%2Bcorvette-carburetor-rebuild%2B.jpg
 
If you have properly baffled valve covers (most don't unless they are stock) the pcv and a breather work fine. I run all the factory stuff on my stroker and even on the road course no issues.
 
I put a stock type PCV on my 360 with a XE268H cam and my idle went up and I couldn't get it down. Also, when I would turn it off it would diesel really bad.

I even backed the idle speed adjustment screw on my Holley 750 DP all the way out so that the throttle blades are all the way closed. No luck there either.

I played with 4 corner idle adjustment screws and that helped, but then couldn't start the car when cold.

So, I took the PCV valve off and plugged the port on the Holley. Maybe I just need a different PCV valve or something.
 
You Really need at least a pcv & breather setup unless you are planning a track only setup. Builds with roller rockers can interfere with using stock type baffled valve covers due to clearance. A lot of folks make mistake of tapping non baffled covers for a pcv not realizing the oll consumption this creates. There are several baffled breathers on the market that will compensate for this like ones recommended for the mopar performance covers.

Oldschoolcuda
 
JoesEdge said:
I put a stock type PCV on my 360 with a XE268H cam and my idle went up and I couldn't get it down. Also, when I would turn it off it would diesel really bad.

I even backed the idle speed adjustment screw on my Holley 750 DP all the way out so that the throttle blades are all the way closed. No luck there either.

I played with 4 corner idle adjustment screws and that helped, but then couldn't start the car when cold.

So, I took the PCV valve off and plugged the port on the Holley. Maybe I just need a different PCV valve or something.
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We had similar issues (without the dieseling) with a stock 60's vintage SBM PCV and a 268-ish cam from Crane. I could tell from listening that the PCV was pulling too much air at idle. We even tired an NOS one; same results. Too much idle air would cause your symptoms.

We changed to an FV191 PCV, that has a lot less air in the PCV at an idle of 14-15 psi, and everything works and adjusts as it should. Here is a discussion:
http://www.forabodiesonly.com/mopar/showthread.php?t=335105
 
And I may very well run into that problem. However what issues would running a tunnelram create with a pcv valve I wonder.....
AJ/FormS said:
I ran two evacs on the street, but found that they work really, really, well. So well that even just one wanted to empty my oilpan through the valve cover. Even after reengineering my baffles, it still pulled enough oil under certain conditions to leave a cloud of oil behind me.I imagined a system to get around that, but,in the end I went withe PCV instead.
Click to expand...
 
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