73 oil pump

[motorhead]

I have a 73 shovel with an oil pump with a .375 ball and spring in the pressure relief hole. The bore hole is .400. Stock pumps have a plunger that is .435. This is too big for the hole on this pump. What kind of oil pump do I have here? Is the ball correct for this pump or is there plunger that fits this hole of .400?

[Ohio HD]

Are you sure you have the right parts in the right opening? The only thing above the 3/8 bearing is a spring and the cap.

[motorhead]

Yes its the taller tower. The hole measures .400. Its a mystery to me and others. The ball check valve next to it also has the same ball size.

[Ohio HD]

Post pictures of what you have and where the parts are fitted.

[motorhead]

It is very similar to the pic above. The hole that part #71 goes into is .400's of an inch. The stock plunger size should be .435 making it to big to fit in the hole. So it has a 3/8 inch ball and spring in it. Mayby it was designed this way. Could be some after market pump.

[kd]

Part #71 ?    typo?

[motorhead]

Sorry, part # 61 plunger style that measures .435 of an inch goes into most stock oil pumps in the pressure relief tower. But my particular pump has hole a ID of .400. So a stock plunger is too big for the pressure relief hole. Currently it has a 3/8 inch ball and spring. Question is, Is this an aftermarket pump or odd year pump. By the way this is stock 73 Shovel. No one that I talked to have not seen a ball in the pressure relief tower. The pump is very similar to the illustration above.

[Ohio HD]

My guess is it's a Sifton oil pump from Tedd Cycle, originating from Taiwan.

[98s1lightning]

My guess is it's a Sifton oil pump from Tedd Cycle, originating from Taiwan.

0.400" × 25.4 = 10.16mm


I would have to agree that's a good guess

0.435" is only 0.0025" smaller than 7/16" which is 0.4375"

I'm not sure if my observations have anything to do with it, but those are my thoughts. Good luck man.

[motorhead]

Hey thanks to all. I am gonna with that idea for now.