PCV, advantage or not?

[Bobby Zlatkin]

Is there an advantage, disadvantage or does it make no difference in leaving the PCV valve connected on a stocker?
Does it provide more air to the engine?
Or, should you just block the PCV port in the intake and forget about it?

[mike natoli]

a pcv working properly will be closed under wide open throttle

[Chris Hill]

I've seen fast stockers both ways.

[Dragsinger]

I have run them both ways and as mentioned above, they are closed at wide open so no difference in performance. However, I think you will see less valve cover "milk" with a PCV. [maybe]

Usually I do not run a PCV but see no problem with doing so.

[Chris1529]

I have a pcv valve on mine.

[gmonde]

i run two,and the engine is sealed good ,no dip stick or breathers,havent had a data to say weather if theres a horse power gain gmonde

[Bill Harris]

I know of someone who tried the two PCV deal, no breathers, etc on an engine on the dyno and lost serious power. The idea is that the PCV valves would make a poor-man's pan-evac, pulling a vacuum on the crankcase. Problem is that like it has been stated, PCV valve(s) is closed at WOT so the idea falls apart. Pressure builds in the crankcase and you lose power.

I have run with and without a single PCV with a breather on the opposite cover back to back. It made no difference except that I get less oil blowing out the dipstick tube when there are two open breathers than when there is one with the PCV. The pressure has to go somewhere, and no matter how well sealed the motor is, there is going to be blow-by.

[Bub Whitaker]

Originally Posted by Bill Harris

I know of someone who tried the two PCV deal, no breathers, etc on an engine on the dyno and lost serious power. The idea is that the PCV valves would make a poor-man's pan-evac, pulling a vacuum on the crankcase. Problem is that like it has been stated, PCV valve(s) is closed at WOT so the idea falls apart. Pressure builds in the crankcase and you lose power.

I have run with and without a single PCV with a breather on the opposite cover back to back. It made no difference except that I get less oil blowing out the dipstick tube when there are two open breathers than when there is one with the PCV. The pressure has to go somewhere, and no matter how well sealed the motor is, there is going to be blow-by.

Poor-mans pan evac, exactley! If you lost serious power on the dyno, and your blowing oil out the dipstick tube, then you need to work on your ring seal. Serious blowby unloads the top ring and blows oil out the dipstick, causing loss of power. This is one way you guys can check to see if your rings are sealing. A good ring seal will pick up with the "poor mans pan evac"

[Jeff Lee]

Bub's right and you wouldn't believe what I have spent on the dyno with PCV's. The good news is they work. But there's a lot of buts and I'm not going to tell all because my engine builder would kill me!. But I will share that not all PCV's are created equal! That's why there are so many part numbers. I bought from the discount stores and the OEM's. I looked at late model (emphasizing the low drag piston ring models) equipped on small blocks to big blocks to the older stuff. There are more effective ways to find HP, this is just one way to get there.

[junior barns]

what does PCV stand for?