setting up PCV

[Buzzmobile]

I bought my car 2 years ago and it did not have any PCV set up so, I am researching what I need. my plan, put a breather in one valve cover (does it matter which one?), and then I need a breather/PCV combo on the other side to be attached to one of my carb inlets/vac (any suggestions?). I have 2 carbs...either one? any advice on which PVC valve, I understand that they need to be "matched" to your engine. I have a 427 SO by Keith Craft, just under 600HP. Any and all help appreciated as usual

thanks
Buzz

[Carnut427]

It doesn't matter where you put the breather or the PCV valve. As a matter of fact, starting around '69 or so they didn't have a breather, call it a "closed system". Run one if you want, it doesn't seem to matter.
I think if you research PCV valves at your local parts store, you'll find most V8s use the same one within a certain year, assuming they'll physically fit (check both Ford & Chevy individually; I know the Chevies used the same one no matter what size the V8 was, I assume Ford did the same. Therefore, it doesn't seem they have to be "matched" to the engine very closely.
Plumb the PCV to the largest direct manifold vacuum inlet, usually on the carb base, on the primary carb.

Dan

[Carnut427]

I forgot about baffles...at least the PCV valve, and preferably the breather too need to be baffled so that they don't suck straight oil. Most valve covers are baffled; if they aren't, Mr Gasket makes baffled breather grommets, part no. 5425; these are sized for Chevy valve cover holes, 1/4" larger in diameter than Ford holes, and the accompanying larger I.D., which will obviously fit a Chevy V8 PCV valve.

Dan

[Jeff Frigo]

Originally Posted by Buzzmobile

I bought my car 2 years ago and it did not have any PCV set up so, I am researching what I need. my plan, put a breather in one valve cover (does it matter which one?), and then I need a breather/PCV combo on the other side to be attached to one of my carb inlets/vac (any suggestions?). I have 2 carbs...either one? any advice on which PVC valve, I understand that they need to be "matched" to your engine. I have a 427 SO by Keith Craft, just under 600HP. Any and all help appreciated as usual

thanks
Buzz

Why do you want to run one?

[Buzzmobile]

I think I have a ventilation problem and thought that would help. I have a new engine and have been having problems with leaks..that are mostly buttoned up, but with high RPM tuning....I am getting some oil. I just need to vent the system and was thinking that a PCV was a good idea

Buzz

[Bob In Ct]

The engine will run leaner with a PCV, be careful. I would just put a breather on each valve cover. Be sure they can breathe.

Bob

[Burgs]

Does anyone see a problem running it thru the carb from under the air filter? Are there any benefits to running a PCV set up?

Brad

[Bob In Ct]

PCV valves are a pollution reducer, not a performance device. They were originally designed to burn the blow-by rather than vent it to the atmosphere.

Bob

[rdorman]

PCV is a win-win on a variety of levels. The PCV valve on one valve cover is connected to manifold vaccuum. Carb or intake makes no real difference. The other valve cover attaches to the air cleaner. Of course in your case you can not do that with the S&H air cleaners with out getting really creative. So, just put in a breather. The PCV valve that the speed shops sell work just fine.

[trularin]

Rich is right.

I would add the following as notes of interest.

1. Make sure the opennings in the valve covers are baffled. And MAKE sure they are properly baffled. You will puff blue smoke if the baffle is not good.

2. Use the correct PCV valve. I had one that puffed after I fixed small baffles and went to the recommended one for a 1971 Boss and the puffing went away.

3. Use the air cleaner as the vent if you can. What I have found is that oil at hi RPMs splashes and/or vaporizes and goes out the vent/breather/hole. I found that when the tube was connected to the air cleaner, the oil went up the tube a bit, but it never made it to the inside of the air cleaner. When using a push in breather, I got drips on the valve cover(s).

4. Use a Vac. gage to see what you have going on with the manifold vacuum. I found that I could reduce the tube size for the vent and get rid of residual oil from the valve cover openning.

Here is what you want to do: By putting this system on your engine, you want to pull the blow-by gasses ( gasses that get past the rings into the crank case ) from the crank case and burn them in the combustion chamber. Since one side is vaccumming the air out, you will need to provide a source of air, hence a vent/breather/connection to air cleaner.

I hope this helps.

[speed220mph]

Here's what I did with my dual-4V tunnel port manifold. It wasn't set up for a PCV valve, however the carbs could've been plumbed. But to avoid routing hoses to the carburetor bases, I drilled and tapped the manifold so it would accept a pipe-to-AN fitting. To that, I installed a 120-degree AN fitting with a push-lock end. At the crankcase side, I installed a well-baffled valve-cover oil-filler cap fitted with a 90-degree fitting that would accept a hose. I then installed an inline PCV valve I found at the local NAPA store.

As trularin said, the outlet must be well baffled at the crankcase side, otherwise the system will draw a lot of oil vapor into the intake system. This will result in high oil consumption and blue smoke out the exhaust system. I experienced this until I found this ugly cap, but it works. I tried plumbing into the crankcase standpipe at the back of the engine, but it wasn't sufficiently baffled, which resulted in a lot of oil being drawn into the intake manifold.

One thing to be aware of is if your engine is on the lean side, an add-on PCV system will lean it out further. So be ready to rejet the carburetor/s to make up for the increase in air flow just in case.