Gday, i have a nitto oil pump with one spring installed(75psi)...but when the engine and oil are cold and during warm up.. the oil press reaches 70 psi at cold idle(which is fine)...but will rise above the springs 75psi to 80-90psi when i rev it lightly(2500-3000rpm).And seems to continue increasing with a bit more revs?. I thought the relief valve would operate at 75psi regardless of the oils temp?? Am i incorrect? Since the car is on a run in tune, it has a 4500rpm limit on it. So ive only been able to get hot pressure readings at about 4250rpm which are....hot at 800rpm-20-25psi, hot at 4250rpm-65-70psi. Im yet to see what psi i get after 4250rpm when hot...but ive got a feeling it may rise above the 75psi..the same way it does when cold? Am running 20/50 oil, bottom end clearances are 2.5 thou. Any info will help. Cheers.

i have the same pump and i am starting to assemble my engine tonight so when running i will let you know what mine is like to compare.

Quote: Originally Posted by grunter01 [View Post] i have the same pump and i am starting to assemble my engine tonight so when running i will let you know what mine is like to compare. Sweet, thanks mate . Some original photos have not been recovered yet.