Adjustable pcv valve

[downsr]

Anyone use a adjustable pcv valve.Have stroker engine that had some oil leaks that have since been repaired.What to make sure that i am not building pressure in crank case.Would get oil leakage on top of timing cover after wide open throttle or cruising around 2500 rpm for a few miles.The engine is a 340 stroked to 416.Have breather on pass side running to air cleaner.PCV valve on other side run to fitting on intake.And how should pcv work at idle opposed to wide open throttle.Just have stock pcv valve from auto parts store on it now.Sometimes i can hear a rattling noise from pcv valve and other times i do not.Do not know much about the adjustable pcv valves and how the pcv valves should work.Thanks

 

[jbc426]

You can insert a plastic plug in the PCV line to the manifold with various sized holes drilled through it to "adjust" your flow. Add a fitting to your PCV line and run a length of tubing inside your car to a vacuum/pressure gauge. Plug the manifold side tube and see if you are building a lot of pressure in the crank case. Excess pressure tends to push the oil dipstick out and push oil past seals and such. The PCV system can only remove so much air. If you have a lot of blowby, it can overwhelm that capability.

My stroker was doing the same thing. My PCV system was sucking several ounces of oil out of my motor per tank of fuel. It turned out that I had a significant air leak at the front lower timing cover on my Magnum swap, because I used the one-piece Magnum gasket on an LA style pan. Once I swapped in the correct 4-piece LA oil pan gasket, the volume of air coming into my crankcase dropped dramatically and no more oil was being sucked out of the motor. Oddly, the oil catch can I had installed as a band aid for the problem prior to finding the real problem, now catches an ounce of water per week. Presumably from condensation resulting from short trips in the winter months.

 

[nm9stheham]

The PCV should pull just a small amount of air at idle from the crankcase so the carb idle is not messed up. At more throttle opening s, when the manifold vacuum is lower, it will open up and pull more air from the crankcase. We had issues for the stock SBM PCV pulling too much air at idle at around 14" vacuum and changed to a FV191 PCV which is a stock GM part designed to run with more aggressive cams in some of their high performance engines. FV184 is another possible PN to do the same thing: pull only a little air with an idle vacuum of 14" or thereabouts.

 

[TrailBeast]

I metered mine down with an 1/8 orifice in the hose from the valve to the carb base because of that exact problem. (my engine actually smoked at stop signs from so much vacuum) even though I have baffles in the covers and foam inside the vent cap.

 

[nm9stheham]

JMHO.... I guess I don't much favor the restrictor fix because it will remain restricted at more open throttle, which is when you need to have more PCV flow.

 

[kowalski440]

http://mewagner.com/
Try Here.

 

[GMachineDartGT]

I've been using all stock valve covers, breather and pcv on my 11.5:1 stroker with no issues. Even on the track the setup works. If you look at the size of the OE baffles vs. the junk in aftermarket valve covers you'll see. You can always put a can in between the

 

[nm9stheham]

I've been using all stock valve covers, breather and pcv on my 11.5:1 stroker with no issues. Even on the track the setup works.

Our issue was at idle; it worked fine with the throttles opened. The stock early PCV upset the air flow into the intake at closed throttle, made the idle mixture screws ineffective, and the car would not idle down properly when slowing to a stop sign. This effect may vary with cam, carb, etc.; our carb is a 670 Holley, Vac sec, and a Crane Z268 cam and about 14" idle vacuum.

 

[TrailBeast]

JMHO.... I guess I don't much favor the restrictor fix because it will remain restricted at more open throttle, which is when you need to have more PCV flow.

Actually at more open throttle the restricted PCV has less vac than ever.

I don't see most people knowing where to set an adjustable PCV valve either.

 

[moper]

I routinely use the GM model PCVs for larger engines.

 

[69_340_GTS]

Actually at more open throttle the restricted PCV has less vac than ever.

I don't see most people knowing where to set an adjustable PCV valve either.

That Wagner valve has excellent instructions (you can view them on their web site). I think most people could set it up correctly by just following the instructions.
No, I did not buy one, the FV191 seems to work on my 340 with a Comp Magnum Muscle 268AH-10 cam (268°I/276°E, .464” lift).

 

[TrailBeast]

That Wagner valve has excellent instructions (you can view them on their web site). I think most people could set it up correctly by just following the instructions.
No, I did not buy one, the FV191 seems to work on my 340 with a Comp Magnum Muscle 268AH-10 cam (268°I/276°E, .464” lift).

I had the same problems as nm9stheham, where there was just way to much flow through the valve so I put a 1/8 orifice plug in the hose and that straightened things right out.