Thread: PCV Valve....Should you use one?

Tweet

Hey fellas, I was just wondering if you should use a PCV on your HI Performance motor. I have been looking around on the net and alot of the pics I see looks as if most motors are using them. I currently am not using one (Chevy 400). I just have 2 breathers coming out my valve covers. If you were to use one...where would you hook up the vacuum for the PCV on your Holley carb (4160)? all of my ports are filled...

1)Rear port is for brake booster line,
2)Bottom pass. side front port is for transmission
3)Top pass. side port is for Vac advance

I think so yes. It reduces pressure inside your crank case which helps with seal and gasket performance. It has also been proven in high perforamnce applications to help some with power, but in those cases the vacuum is created by running hoses from the braethers to a check valve at the header collector.

For connection, you should have a place for a fitting on the intake manifold, either at the base of the carb at the back or on one of the runners. Put a fitting there and connect your power brake booster to it, then use the large fitting on the carb for your PCV

Hope that helps

Pat

Denny your everywhere on this machine... Thanks for the reply...you too Stu... I think I will try the PCV valve. I think the method Stu gave would work best with my setup because I am already running a 1" carb spacer w/ the 4 holes. If I added another adaptor it wouldn't fit under my hood. But on the other hand I saw in your post Denny that when you take vacuum from the runner on the intake manifold, that cylinder will miss when braking...I don't want that and that seems to defeat the purpose. But I do have a 3/8 fitting right behind the carb on the intake that is called the "vacuum" port. So what gives???? what do you use this port for? the tranny?
On another note I seem to get alot of steam or smoke coming from my breathers is this normal?


By the way I finally got rid of the ping...it was the valves I had another bent pushrod...evrything seems good now though.

I think I'll try drilling my spacer, it shouldn't matter what hole I drill into right? my spacer is of the 4 hole variety.
Also anyone got the method for the "hot adjusting method" for hydraulic valves w engine running...I know it 's messy But I heard it's the best way. I have already broken 2 pushrods now doing it the crane cams way.

What is their way?

With the engine running find a start point. Back it off until it ticks. Turn back down until the ticking stops and then go 1/4 turn. Lock it down and move to the next.

Of course this only works if you can hear them.

I know you said you have a lot of "steam" coming from your breathers. When I built my first engine I thought the PCV looked stupid and left it out. About two months later my plugs started to foul out every day. Yea thats right, I blew every valve seal in both heads. I now use a tee in the back of the 4160 for the PCV. That steam is either the seals or the rings starting to go.

It's my understanding that you cannot get enough blowby gasses out of non POSITIVE crankcase ventilated blocks without really large vents like at least 4 square inches. Road draft tubes and the like often allowed large piston ring unseating pressure buildups.

I have no direct experience, though I always installed PVC valves on any engines I found with out them.

What do I do if I want to run a PCV valve on a tripower setup? Take the PCV from the valve cover to the center carb base? Does anyone make a PCV carb base spacer with the PCV inlet that will fit the Rochester 2GC small base carb? I've been trying to figure this out for a while as I want to run the tripower on a 350 block which of course has no road draft tube.

On my 34, I run a PCV on my 350 from the valve cover to the front center vacuum port on my Edelbrock Performer 600 carb. Never any problem with this one. There is no facility for a pcv on my 57 Olds. It has the road draft tube that exhausts when the car is run at speed for a long period (several hours), but the valve covers (Offenhauser) have no facility for a pcv valve, and not sure I would want to attempt to install one. The carbs, like Old Gold's, are Rochester 2G's (Olds J2). There is a small vacuum port on the driver's side in the rear of the #3 carb, that is connect to a wiper unit, that is no longer used (wipers removed). This set up has been this way for nearly 50 years, and motor doesn't seem to show any sign of disfunction.

Is there a pcv solution that does require drilling and tapping? Or is my next step as already planned, which is to eventually replace the aging 371 with a new fire breathing ZZ502.