Amc 360 Loses Oil Pressure

Been working on a 1980 something CJ7 that has a AMC 360 installed. After setting for a long time it will not build oil pressure. I have to pack the pump with Vaseline, pull the distributor and use a drill to spin the pump to prime it. Works fine until an extended period of not running. Any ideas?

 

And the oil pump gears/housing appear okay ?

 

Is there a non-return check valve which is leaking down?

 

New gears, housing looks ok.

 

I was told by the owner he had a oil pump kit put in it, new gears, spring and check valve. Last time I had it in the garage I had the pump apart and the gears and housing looked good but I didn't check the spring and valve. Probably should have. I seem to remember there was two types of housings on the 304?

 

I would check the anti drainback valve as well as the bypass valve. I've seen the bypass valve stick in the bore. While this usually still allows the pump to pick up pressure, it can be low to non existent at idle.

 

Not every oil filter works on an AMC motor. Try another brand or one that specifically states to be anti drainback.

 

X2. The incorrect filter can allow gravity to drain the pump and pickup.
-Donny

 

Could someone supply the brand and number that has this anti drain back valve filter for the 304.

 

WIX 51258, FRAM PH25, BOSCH 3423, FRAM HP5

 

Yep. Grab the wix. 51258