PCV valve question....Oil coming out of dipstick.

[Stormrider]

I have a 77 CJ7 with a AMC 304 . Just rebuilt the motor on it. When it runs, oil is coming out of the dipstick. I did put a pcv valve that I got from Autozone on but it seems like it's just a big black plastic tube that's hollow in the middle. Also, is it suppose to connect to the port at the bottom of the carb in the back? I unhooked the pcv and didn't feel too much vacuum pulling from the intake and the motor runs fine. Actually oil doesn't come out of the dipstick when I don't hook up the pcv. Is that normal for these motors? Also, the oil filler cap has a port with a hose on it. Is that suppose to hook up to the bottom of the air cleaner. I have an aftermarket Holley round air filter and I believe there's a port for a hose underneath. The previous didn't have any of these hoses hooked up so I am trying to figure them out.

Thanks,
Storm.

 

[Cheepjeep85]

Yes the pcv valve connects to the large port on the back side of the carb, (assuming its the factory 2bbl carb) it is supposed to have full manifold vacuum. I do believe the hose on the oil cap goes to the breather (somebody correct me if I'm wrong). PCV stands for positive crankcase ventilation, it use full manifold vac to pull crankcase gases from the motor, and sends them through the combustion chamber out through the tail pipe, all to keep your motor from blowing seals and blowing oil out of places it should not come from like the dipstick tube. Before the pcv system most vehivles had a blow by tube coming from the valve cover or else where and just vented out onto the ground oil and all.

Droooiiddd 2

 

[Sasquach]

Another thing to add to Cheep's fine explanation is pcv valves are engine specific and metered by flow to suit each engine model, should not be a hollow tube as the Zone sold you?

 

[Stormrider]

Does anyone happen to have a part number or a picture of the one that I need for my AMC 304 ? I think the one that I have is hollow and is pretty big like at least 3/4 inch. The previous owner had the pcv hose hooked up to that oil filler cap which I didn't think was right. He also had a plug on the back of the carb where the pcv hose is suppose to go.

 

[81laredo]

I am going through a similar situation. Pull the Hose going to thew PCV Valve and ensure that it has Vacuum. Now then there needs to be a Line from a Valve Cover (or something) to the Air Filter or simply a Breather Cap (to atmosphere) to help relieve any Internal Pressure.
Good Luck.

 

[Cheepjeep85]

Another thing to add to Cheep's fine explanation is pcv valves are engine specific and metered by flow to suit each engine model, should not be a hollow tube as the Zone sold you?

^^^^good point