Oil catch tank vs PCV/breather

[951mat]

I've read lots of posts on this issue and still puzzled slightly. I understand how a PCV valve works. I currently have one going to the carb base and a breather in the other valve cover of my FE 427. I'm thinking of building a catch can with a breather on top and plumbing both valve covers to the can. I can't see what this would hurt. It sounds like people haven't seen ill effects either way with or without a PCV, as long as the crank case is vented well.
I personally like the idea of not burning oil vapors thru the motor. Not sure how much this really lowers the octane, but my engine is probably on the edge burning crappy 91 octane fuel. I also don't care for the weeping valve cover breather either.

Mat

[Tom Kirkham]

Your engine will leak less oil with a PCV valve. If you use a catch can be sure to run a breather on the can. If you are going to track the car be very careful about the right side valve cover filling with oil...

[big-boss]

Tom, Can you vent the engine to the catch can ala Original and put the PCV on the vent of the catch can? How do you keep the oil from building up in right VC?

[Tom Kirkham]

boss,
I have not seen a puke can and PCV used together. I am not saying that it can't be made to work but I don't know how...Oil filling up the right valve cover is only a problem on a race track with left turns and a very good driver. What we did to solve the problem was to weld in bungs so that we could put hose fittings on the valve covers and run the oil into a puke can. The puke can was vented and also has a drain back to the oil pan.

[ST]

I've been using this setup for a few years now with no problems.IMG_0658 - Club Cobra Photo Gallery

[Jamo]

I run mine assactly like the original...with the oil separator tank (not really a catch can since it vents to the air flow via the tube to the bottom of the chassis and drains back to the pan as Tom indicates) and no pcv. It's how them boys in Provo set it up.

I also run a K&N vent on each valve cover. Works muy goodo.

[RICK LAKE]

951mat Mat if you do 95% street driving, the PCV system will work just fine as long a you have a breather for each valve cover. If you get the racing bug, you might want to go to the tank. For racing, autocross and roadracing. I run just a PCV on my car with a breather in each valve cover. They are the tall ones. I also have resistors in both heads for oil control. I run .080". This allows my heads to fill with oil, but not overfill to the tops. The oil was checked at 3,000rpms. The valve springs are covered and the oil is draining back through the return holes and pushrod holes to the valley. If you go racing the tank might be the way to go. I drive street classes. The pros use both tanks and vacuum pumps on there motors. You can test your motor for pressure with a vacuum,pressure gauge. If you hold vacuum at 3/4 throttle, stay with the PCV if you go to pressure, you may want to add a tank and drain. Do you have any blue smoke coming out of the side pipe on hard turns? if not, PCV will work fine. For the worry about the oil mist getting into the cylinders, there are orifaces to control this. The gas mist will mix with the oil mist and burnup. I would worry about this unless you are running a 13-1 compression motor. Check the spark plugs after 500 miles and see what color they are. Then you can go them there. You might want to think about adding an Accusump to your car as a peroiler for the motor and protects it if you go racing or pull high G's in autocross or roadracing. They come both manual and electric. You can mount it under the hood. I my case it has saved 15k motors. Just a thought. Rick L.

[speed220mph]

It's usually best to run a PCV valve. The valve is closed at idle and wide-open throttle (WOT), but draws vapors from the crankcase to the intake under all other throttle positions. At WOT pressure in the crankcase is being pushed out the breather/s since it can't pass the PCV valve, that would otherwise lean the A/F mixture. This means you can run a puke tank on what would be the intake side of the crankcase, i.e., on one side is the PCV circuit and the other is the breather circuit. This allows filtered air to be drawn into the crankcase through the puke tank when the PCV valve is open, but vents the crankcase through the puke tank at WOT. Using this methods gains advantages of both methods, vapor removed at part throttle and crankcase venting at WOT. Just make sure you have a "fill cap" on the puke tank or valve cover that filters air when it is drawn into the crankcase.

[sexzsn8k]

ST/Jamo/Tom, quick question, where can I get the rubber seal that is around the top edge of the turkey pan on both of your cars ? I've tried to locate it but to no avail. Can you give me a suppliers name and I can take it from there. Thanks, Jim

[speed220mph]

Can't give you the exact number, but it looks like a simple door seal/weather strip that's designed to push over a weld flange. I imagine it's available from JC Whitney. All you need is an idea of the seal cross section and length to purchase one.

[ST]

Originally Posted by sexzsn8k

ST/Jamo/Tom, quick question, where can I get the rubber seal that is around the top edge of the turkey pan on both of your cars ? I've tried to locate it but to no avail. Can you give me a suppliers name and I can take it from there. Thanks, Jim

I altered the rubber weatherstripping Shelby uses that fits between the body and inner fender tins. It's probably similar the the stuff Kirkham uses, too.

Here's another look.
1b - Club Cobra Photo Gallery

[J Persons]

This is my air-oil seperator/ PCV/catch can. It's actually a Stefs puke can, filled with stainless steel mesh, and with the PCV in the top. The inlet is in the center, and comes from the left side valve cover. The right valve cover is connected to the air cleaner and draws fresh filtered air into the engine. There is also a drain in the bottom of the can for any liquid oil that may have traveled up the hose. So far, the engine seems to get only vapor, I haven't detected any oil at the PCV. This is a small block, but I don't see why it wouldn't work on any carbed engine. John