When setting main relief valve do you take engine to full rpms?

[Leejohn]

Because he adjusted the relief valve higher.

I took it he hadn't set anything yet.

 

[SPYDERLK]

4570Man & RickB that should be true and I woulde say in most cases it is , but why is he getting more psi when he ups the rpm and getting more flow? Something is holding the oil back.

It takes a little more pressure to push the oil thru the RV faster.

 

[RickB]

4570Man & RickB that should be true and I would say in most cases it is , but why is he getting more psi when he ups the rpm and getting more flow? Something is holding the oil back.

Because a coil spring compresses more with incremental pressure. X lbs for the first millimeter, x+ lbs for the third millimeter of compression. But at full compression any properly paired relief valve will exhaust full pump flow. Every time.

 

[Leejohn]

Well OK.

 

[Hersheyfarm]

I took it apart to clean it and make sure no rubber parts in it like I had on backhoe reliefs. Its an m59. I adjusted it at idle with new fluid/filter change and not really warmed up. Then I thought I better check at engine rated rpm, and it does raise psi a little. so it is safe to say hold back of flow does raise psi a little. not much, and probably way less at operating temp. Already took guage off or I would test it when warm.