oil pressure problems

[rudy herrera]

my oil presure goes down when the car has worm up the oil presure goes dow but when i get back on the gas the oil presure goes back up when i put the new oil pump i used some oil i never used before it was realy low quality cuz at the time it was all i could afford could this cause this problem it didt do this when the old oil pump was working good

 

[Lawbreaker5.0]

sounds normal to me. when i hit the gas, pressure increases and at idle it goes down. Now if it drops pretty quickly or sporadically than check the sending unit, cuz they do go bad too

 

[camachinist]

OP, could you put some numbers to this? Install a known-good mechanical gauge which reads in PSI and get us some numbers....

It's normal for most engines to have lower oil pressure at idle and then for the pressure to rise as rpm rises, to the point where the pressure relief kicks in. Oil pumps are positive displacement pumps and are rpm dependent for volume and pressure, relevant to the clearances in the engine and viscosity of the oil. Ergo, tighter clearances and higher viscosity will generally yield less of a rpm-driven pressure differential, all else being equal, with the reverse leading to more of a pressure differential.

FWIW, since I like to run a lot of clearance in my racing engines for cooling, my numbers are generally 30 psi at idle (about 1000 rpm) and between 60 and 65 psi at 7500 rpm. That's running a modified OEM oil pump and restricted oiling system and straight 50 weight. Old-fashioned tech. YMMV

 

[rudy herrera]

radiator question

is the radiator from and automatic 5.0 the same as a 5 speed one

 

[stykthyn]

yes. just plug or pinch off the lines for the tranny cooler if you have a 5spdcar