hello, as you might already know, i built a 302 bored .060 with a mellings high volume oil pump about one year ago.it is now in an 89 mustang with a 5 speed.now i have 10w30 in it but have been told that the oil i have is too thin for my needs. it idles at about 65 psi when coldand gets to about 80 psi when revved.but now summer is here in texas and ihave noticed when warm, the psi would be at 30 at idle and 60 when revved. sometimes when driven longer it gets to almost 0 psi at idle. there is no metal shavings in the oil andit is at the right fill level. i am thinking it is just the thin oil. i want to put castrol 10w50 in it or maybesome sort of 10w40. what would be the best route to goand what do you think the low psi is being caused from. the motor does not knock or tick at all. i am using a mechanical oil gauge too. i don't really know the mileage on this engine but it can't be more than 1500 miles old as this is just my project and not my daily driver. sorry about the lack of using the spacebar. i was on a different pc and the keyboard wat sticking or something.
funky oil pressure
- Thread starter dastang2
- Start date
_jb_
New Member
The changes in psi could be due to the oem gauge. Are you using the oem or do you have any aftermarket gauges?
if you have a fresh motor, i would not want to run too thick an oil in it, unless it was machined with fat tolerances.
i would avoid the larger variances in cold and hot weights (10-50 you list, or even 10-40) - those weights tend to break down (dino oil mainly) fairly quickly.
your pressure does not seem bad, except for that whole almost no pressure thing. LOL. i like the cooler idea. im thinking of doin one myself (tucson). over 100 and the oil gets hot.
i personally would go to a quality PAO synthetic 10-30 or slightly thicker (if your motor is broken in enough). remember, pressure is a bit indicitive of resistance (molasses would have awesome pressure), but that does not mean it FLOWS well - which is more important.
also, with some Hi Vol pumps, they can bleed the pan dry (pumps all the oil out of the sump so fast, none has returned yet). not that i think this is any of your problem, but thought i would toss that out.
good luck.
i would avoid the larger variances in cold and hot weights (10-50 you list, or even 10-40) - those weights tend to break down (dino oil mainly) fairly quickly.
your pressure does not seem bad, except for that whole almost no pressure thing. LOL. i like the cooler idea. im thinking of doin one myself (tucson). over 100 and the oil gets hot.
i personally would go to a quality PAO synthetic 10-30 or slightly thicker (if your motor is broken in enough). remember, pressure is a bit indicitive of resistance (molasses would have awesome pressure), but that does not mean it FLOWS well - which is more important.
also, with some Hi Vol pumps, they can bleed the pan dry (pumps all the oil out of the sump so fast, none has returned yet). not that i think this is any of your problem, but thought i would toss that out.
good luck.
It is certainly worth you time to try hooking up a different guage before you start replacing any big-ticket items. I find it very odd that your engine would run that much oil pressure while cold and zero when warm...especially with 10w-30. I think you should get a second opinion with a different guage and go from there.
i also may have gotten a little water in it because i wass missing an intake bolt. and when i pulled the intake, there was about a knickle sized water drop in the lifter valley. but that did not show on the dipstick or the oil cap. i check my oil. water most likely got in it when i was washing the motor.
