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Do I Need A PCV?

pomai

pomai

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I included the Cam Spec so you all can see and give your opinion on weather I need a PCV or not.
My research on the internet says yes I do, what do you guys think?

I'm looking at M/E Wagner Performance Dual Flow Adjustable PCV Valve.

Dart SHP Block
Mahle 10.5:1 Pistons
AFR Heads

P1040291.JPG
 

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  • Cam Spec.pdf
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pomai said:
I included the Cam Spec so you all can see and give your opinion on weather I need a PCV or not.
My research on the internet says yes I do, what do you guys think?

I'm looking at M/E Wagner Performance Dual Flow Adjustable PCV Valve.

Dart SHP Block
Mahle 10.5:1 Pistons
AFR Heads

View attachment 325635
Click to expand...
 

Attachments

  • Cam Spec.pdf
    469.6 KB · Views: 4
PCV also prevents pressure from building up in the crankcase. Without it that pressure can push oil out past the lip seals...
 
yes you need a pcv, if you don't you will run the risk of filling the crank case with the proper air fuel ratio and blowing your oil pan off.
This happened to cars a lot in the 50's and early sixties equipped with road draft tubes. Road draft tube, works like a vortex tube, at a certain speed the road draft tube would "vacuum" out the crank case of fuel vapors. This system only worked well if the car was drive at higher speeds for long enough time periods, on mechanically sound engines. Engines that didn't get driving at the correct speeds or were worn out would eventually build up the enough fuel in the crank case and boom no oil pan. The positive crank case ventilation is the solution to passive road draft performance
 
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Well, since your breathers don't go back to your intake... yeap. Those breathers will eventually fill with oil and then drip down the side of your motor. Plus all of that condensed vapor is going to eventually cover the motor and collect dirt.

At 10.5:1 and a .027" ring end gap you're looking at about 1% leakage. It's a lot of air.

If you eliminate one breather and run the other one to the intake tube I'd consider not having one. But if you don't have a PCV in one valve cover and the breather in the other, it will shorten oil life.

Short answer is... one breather tube to the intake tube after the filter... the other valve cover goes through a PCV to unported vacuum on the intake.
 
CyberSniper said:
Well, since your breathers don't go back to your intake... yeap. Those breathers will eventually fill with oil and then drip down the side of your motor. Plus all of that condensed vapor is going to eventually cover the motor and collect dirt.

At 10.5:1 and a .027" ring end gap you're looking at about 1% leakage. It's a lot of air.

If you eliminate one breather and run the other one to the intake tube I'd consider not having one. But if you don't have a PCV in one valve cover and the breather in the other, it will shorten oil life.

Short answer is... one breather tube to the intake tube after the filter... the other valve cover goes through a PCV to unported vacuum on the intake.
Click to expand...

PCV on the driver side? Breather tube on the passenger side, or does it matter what side.

Thank you all for your help.
Ed
 
Doesn't matter. Make sure you have filtered air for your breather.

Thou the rear right is out of the cooling fan air flow, breather would stay cleaner longer.
 
pomai said:
PCV on the driver side? Breather tube on the passenger side, or does it matter what side.

Thank you all for your help.
Ed
Click to expand...

Doesn't matter at all, just do whatever you think looks best/cleanest. I have gotten into the habit of using the through-hull inboard boat fuel vents for the valve covers (but requires valve cover removal). They come gasketed and are sealed tight/don't fall off and have a barb on them for the hose.
 
GM always had the breather on the passenger side valve cover,and the PCV valve on the drivers side--probably to encourage a "cross flow" by pulling fresh air in from the opposite side of the crankcase..
Having both on the same valve cover might not work as good..
 
diesel4me said:
GM always had the breather on the passenger side valve cover,and the PCV valve on the drivers side--probably to encourage a "cross flow" by pulling fresh air in from the opposite side of the crankcase..
Having both on the same valve cover might not work as good..
Click to expand...

Thank You,

Ed
 
This diagram will explain it better--if you had the pcv and breather on the same valve cover,the pcv would likely only pull fresh air in from the breather,instead of creating the proper vacuum in the crankcase to be effective..

chevy pcv flow diagram.jpg
 
diesel4me said:
This diagram will explain it better--if you had the pcv and breather on the same valve cover,the pcv would likely only pull fresh air in from the breather,instead of creating the proper vacuum in the crankcase to be effective..

View attachment 325780
Click to expand...

In this diagram Filtered air does not have to come from the engine air filter, you can pull from a valve cover breather filter like you already have. The difference is just emission standards between and open(pulls from breater) and closed(pulls from air cleaner) PCV system.

The main difference is that with open systems, if your engine produces enough blow by it will overload the pcv valve and leak out of the valve cover breather to atmosphere. With a closed system, if that leakage occurs, it gets sucked into the intake and burned anyway.

Here is a good article describing the whole system
 
I ran dual PCV valves on my last 454 engine. My cheap Chinese chrome valve covers cam with a smaller PCV grommet on one side, and the other side had a breather cap size grommet so I found a reduced size grommet for that side, which allowed me to plug in a PCV valve. I ran a vacuum T-line that connected both PCV valves to my carburetor intake manifold vacuum port.
 
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1-ton said:
I ran dual PCV valves on my last 454 engine. My cheap Chinese chrome valve covers cam with a smaller PCV grommet on one side, and the other side had a breather cap size grommet so I found a reduced size grommet for that side, which allowed me to plug in a PCV valve. I ran a vacuum T-line that connected both PCV valves to my carburetor intake manifold vacuum port.
Click to expand...

What did you use to let air into crank case?
 
Did you plumb to valve cover, or have an old road draft tube block ...?
Most valve covers only have 1 hole and maybe an oil fill.
 
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