5 replies to this topic

[Oak]

I just finished doing a complete rebuild on an Onan P220 and have a question on the oil pressure. I did not change the bypass spring and I'm running at 20 psi at 3400 rpm. Is this normal? Here is a vid of the first start.

 

https://www.youtube....h?v=EgdQ_-dg2Vk

[KennyP]

My P220 has 50 lbs. after warming up. 60 when cold.

[larrybl]

Seems low, I did replace the by-pass spring on my N52M, and get almost 40 psi at idle. https://www.youtube....h?v=6m5CRK5diN8

[olcowhand]

Should be around 35psi+ at high speed with a tight engine.  20psi is a minimum acceptable pressure.

[Oak]

That's what I was afraid of. I didn't pull the pump apart but I think I measured the bypass spring and it was within spec. This engine has all new 20 over pistons, crank was turned 20 under with new rods also installed all new cam and main bearings too. Do you think I should just try a new bypass spring to see if that helps? What else could it be besides the pump or spring?

[larrybl]

I would replace the spring first, always go from easiest to hardest. I had to remove my N52M 3 - 4 times chasing a oil pan leak, finally found the problem, I had swapped the 3" intake bolts with the 2-1/2" pan bolts, could not get the pan to seat.