Necessity of PVC Valve

[Joe Mopar]

Are they? :edgy:

My Dodge 440 has a 440 installed in it. It has M/T valve covers with no provisions for a pvc valve.

I guess I could drill one in and get the grommet, or just get a grommet to take up one of the oil filler breather caps.

I've seen pictures of engines on the forums that appear not to have any, 1 side, or both sides.

What's the story? Need any more information on the motor let me know.

 

[65-440]

PCV is good, you can use one of your existing holes in the valve cover to install the valve then run a hose to a manifold vacuum port. uses engine vacuum to pull crankcase pressure out of valve covers and recycles gasses. or ... you can use that valve cover hole already there and run a pipe down to your collecter and use exhaust flow to create a vacuum on the pipe to pull the pressure out and push it out the tailpipe ... either way PCV reduces piston ring wear .... right now mine is set up like yours, just venting into atmosphere !

 

[69 Runner]

Yup. You need it. I would bet that if you looked inside those covers you would see the "circle" at the opposite end from the breather is pre-cut on the underside to make a "knockout" for a PCV valve

 

[68383GTS]

Yes under the circle on the valve cover there will be a knock out.

 

[Joe Mopar]

So is just one side sufficient?

 

[69 Runner]

That's all the factory had. But if it's a big dog motor then maybe not

 

[Joe Mopar]

Then if I do both sides, I can come off the center port where I have that hose coming off now and add a "T" and go to each side?

 

[generaljmwlee]

some one took out the back plug on mine for a pvc valve just got to buy the new grommet

 

[Joe Mopar]

So is venting both valve covers unnecessary? :edgy:

 

[65-440]

venting is good, especially with no PCV

 

[Joe Mopar]

What I mean is if I put a PVC valve on one side is that sufficient or would it be better to do both sides? Or is that just overkill?

 

[HitIt]

One should be fine on a street motor. If it's an all out race machine that is at high RPMs then the more venting the better.

 

[daredevil]

All out race motors usually use a vacuum pump.To answer the question of how much is sufficient I would say to hook up one side to a pcv and use a new vent cap on the other and run it. Then check the vent cap for oil inside it. if its seeing pressure it will be oily but if its under a vacuum from the other side it will be relatively clean. Before i vented mine it would blow oil out of the dipstick when i hit it.

 

[1badstroker]

It all depends on how big of a cam you have also. Check your vacuum, You need at least 12 to 14 inches of vacuum to make the pvc valve work right. I use a crankcase evacuation system to pull the pressure out of the motor. The only problem I have and I think is common is they don't work well at an idle. I seen a big difference on how the car performed and how much better the engine idles. The kit below is from jegs and is the one I have. Hope that helps.
Moroso 25900
Crankcase Ventilation System

Item# 710-25900
Ships Today
Only $55.99

 

[Meep-Meep]

If you are using a PCV then you should only pull a vacuum on one side and let air in on the other. That way the air moves through the entire crankcase.

 

[383man]

If you are using a PCV then you should only pull a vacuum on one side and let air in on the other. That way the air moves through the entire crankcase.

That is correct. It needs to pull air thru the eng or in one v/c with a breather and out the other thru the PCV valve. I run the MP .557 cam and it pulls enough vacum that my PCV valve works. Ron