A pcv valve is a very simple oneway valve, it has a loose ball and seat that seals in one direction, flows in the other. It has nothing to do with causing a vacuum leak, unless it's plumbed wrong. It's sole purpose is to prevent carb backfires from reaching the crankcase, nothing else. Back in the day before emissions, the crankcase was vented via metal tube that came off of the top of the valve cover and exited near the bottom of the engine.

The pcv valve is simply a safety device as oil can become fuel saturated and the crankcase can fill with fuel vapors.

 

I have noticed just now that my oil filler cap has a small crack. Can that be causing the lung mustard or play a part in it. Trochiod, are you saying to put a "T" on the oil filler neck nipple and run a "T" to the air cleaner vent for the gas with a pvc valve to act as a checkball? Remember I have the rats nest still.

 

If you have the rats nest still, you shouldnt have the need to add a PCV valve. The reason you would add this is becuase by removing the rats nest you remove the stock crankcase vent.

 

Replace the cap....the atmosphere is generally loaded with moisture in LA, so you've pegged the source right there. A bit of it comes from blowby from the rings, but separates from the fuel or oil once it hits the oil pan...cooler surfaces like the filler neck is where the water will drop out of gas state to liquid state which is why you see rust up there if you don't have the ventilation system working. If you have the rat's nest on the car, just replace the tube that runs from the neck to the nest and you're done.

The diagram is for SA cars. The charcal canister on the lid was replaced by a charcoal canister on the fender for the FB's, I believe. It just pulled sitting gas vapors from the intake and carb back into the top of the carb to be properly mixed to burn for emissions sake.

 

Well after reading about PCV valves in the old thunderbird book. The purpose of a crankcase vent is to release pressure from building up. So if there is no vent it will actually cause a oil leak on the weakest seal.

 

Come on over and ill give you mine.

I got a aftermarket one from a very good friend and I have a spare laying around.

PM me.

-nick-

 

A big problem with any domestic big cube V8. In the day, you simply had a breather on the each valve cover to dissipate crankcase pressure. Again, emissions requirements by the feds mandated the PCV system to take those gases to be run into the engine again for additional "burning" in the power cycle of the engine.

 

Yeah I just don't get emissions. They have to make it so complicated that you have to read a book about it just to understand one car. About the pressure though, the airpump used to draw all of that stuff back into the engine since like you said it doesnt have a breather. Now since we all removed the air pump, we need a second draw using the intake.

Its amazing how much I was taught in one day lol.

-nick-

 

Ok I got a bunch of different vacuum lines. 5/16th and stuff like matt said.

I got a pcv valve. All it does it block air from going two ways. Its like breathing out and not being able to breath back in like trochoid said.

Time to get my car back from my brother and hook it up. He borrowed it for a day or two.

-nick-

Ill update in a week to tell the results of now and after.

 

Which intake slot do I put it on. I have it on the one to the very right that has no suction. I figured it was a vent so the pressure or something would push it.

Is this right or do I need one that has full suction....

-nick-

 

If I could ever get some good weather here, I will go take some pics.

 

If I put the vacuum line to filler cap to one that is sucking air my idle will start to mess up. If I just put on that is sitting there its fine. Which one am I supposed to hook it up too. Theres only a estimate 7 on there.

 

Forgot my PCV valve. woopsy...... lol

 

pictures yet?

I swear, I cannot figure out how it was so easy for you all. I deffintly do not have the right stuff because idle never is right with it hooked up.....