View Full Version : oil pressure question

12-05-2003, 12:32 AM
ive been searching on the webste and everyone is saying that oil pressure should be at around 20-25psi on idle my new motor on idle only puts out 11 on idle, and at 2500 it puts out 50 psi

im takign it this is a bad thing? my clearances were all within the specs. im just wondering if i should worry..... its been like this since i built the motor and its been a while since then. ive put more than 3000 miles on it and its running great, and when i look in the oil cap theres always moving oil in the valve cover, and when it first starts it gets 68ish psi.

so i dont know... shoudl i worry about it or forget it and wait till the oil pressure drops more

btw im readign the oil pressure off an automoter guage, Pro comp ultralite.

and im running 10w30 regular oil

12-05-2003, 01:24 AM
I run synthetic oil.....5w30.....and I get 63psi at cold idle. 25psi at warm idle, and 53psi will driving over 2000rpms. This is what the ford manual says the pressure should be, and my pressures prove that. The pressure should never get as high as 75psi. I believe there is a pressure valve in the oil pump that prevents the pressure from getting that high. I think the max pressure is something like 68psi??? Anyways, your idle pressure seems a little low. This could be caused because you're using a different weight oil than what is recommended. During the rebuild did you get a new oil pump (94-95, 8 tooth style) or get a rebuild kit. The rebuild kit cannot always repair the pump. Anyways, If it was me, because i like my things perfect, i would be very concerned of the weird oil pressure. Just a thought...others might know more than me, but ask around, seems a little low to me.

12-07-2003, 05:37 PM
im sure its not my berigns because i checked everuy single clearance in the bottom end and they were all within the specs...

another thign that makes me think its the oil pump is that my old motor spun a cam bering and that was putting metal through the oil pump which would damage it...

and the weird thing is my oil presure once the car is hott will not go over 50psi no matter how high i revv it it gets to 50psi at 2000rpm and will not go higher and its also weird that on idle its at 11 and then as soon as i even touch the gas like bring the revvs up to like 900 or 1000 the oil pressure jumps to 30 psi

so i dont get it i think its the casing on the oil pump cause i only rebuilt the internals of it.... do u guys know where to get a new oil pump casing/whole thing ?

91 XR7
12-07-2003, 06:11 PM
Um yah... I have no idea what my oil pressure is at (maybe 0-1 at idle and like 10 at 2500 :) )

But oil pressure also revolves around Oil type and weight, and Oil filters too.. not just bearing clearances

not all dino based oils are created equally.. same with synthetic oil, and semi synthetic oils...

it also depends on the engine persay.. Heck we have like 170Hp aircooled VW engines at work that have like 10PSI at idle (@900RPM) but like 60+ at 2500Rpms also our 911 powered car runs at like 50+ PSI at idle (but that's cold with 20W50 in the Sump tank :) ) and should be around 8 PSI hot at idle and a 3.2L 911 motor is not a cheap motor either but that's how porsche built it...

12-07-2003, 06:15 PM
im gonna try a new oil pump but i cant find a dealer with a pump designed for sc's they only have the rebuild kits which ive already tried

soo... i searched our site and supposedly we can use the 96 and up 8 tooth pumps off 3.8L mustangs so im gonna try n find a place to buy that... or the melling m246 oil pump...

12-07-2003, 06:39 PM
Stephen, it may well be that you have an issue with your oil pump/timing cover. Replacing the oil pump will not help things if your timing cover is worn. Rather than go to the trouble and expense of possibly having to replace the timing cover and/or oil pump, I would just run a little thicker oil. For winter I'd run 10/40 and in the summer run 15/50. That should get you where you want to be with oil pressure. Remember the old rule: 10psi/1000rpm is totally safe. Chances are there is nothing wrong with your motor at all.

12-07-2003, 11:44 PM
ya at 1000rpm i get about 20 -25psi

alright, i'll try that , i was thinking of 20w50 lucas oil but is that too heavy?