Oil pump losing its prime

[88BattleWagon]

What could cause the oil pump to lose it prime. My Jeep is backfiring, no power and the rockers are making alot of noise. That is until repack the oil pump with petroleum jelly and then it runs like new for about 20 miles and then begins losing power and getting louder. New oil pump about five years ago. :(

[Crazy_Jeepman]

I would not think it would loose prime. Do you actualy have any oil pressure when all the bad noises are going on? Do you have oil pressure after you pack the oil pump? Sounds to me that it is possible that it quiets things down while the jelly is in the system, and things go back to normal after the jelly breaks down. Not realy having anything to do with prime, just the extra thick lube it has for a few minutes. Sounds more like a flat cam and bad lifters. A very common AMC problem. I hope this helps, may not be the cause but it is my guess and it is where I would start. Good luck.

[88BattleWagon]

The oil pump actual goes dry or almost dry after driving about 20 ir 30 minutes. It looses all power and starts backfiring out of the carb. But I can reprime the oil pump and it runs great.

[SpruceMoose]

if it is actually losing its prime, i can only think of 2 reasons: too much clearance in the pump itself, or a small leak on the intake side of the circuit, anywhere from the pump back to the point where the pickup goes under the oil level in the sump.

[Snakeyes_Tx]

What does your pressure read-out tell you?

[88BattleWagon]

My oil pressure gauge reads peg out at the top all the time, probably not correct. There is definitely something wrong with the oil pump. Could it be the gasket is to thick. I did make it myself but it was just as good as the old one in shape. I had put the cap on the oil pump without the gasket and it locked the distributor up. So I made a gasket.

[SpruceMoose]

yep, if that gasket is too thick than you have a huge amount of clearance in the pump. try an original equipment gasket and see what you get.

[<88battleWag>]

Thanks Spruce, That's what i'll do.