dmalhi1

Hi guys just wondering about my oil pressure
my cars oil pressure stays at 540 kPa always it never comes below right when the car is fired up the pressure is at 540 even when i hit the gas or let go of it it stays at 540 the only time i saw it drop to 320 was when one day i had the hood opened up and showing a buddy and had started it up when i tapped the gas a bit while in park to show off the throaty sound of the exhaust i noticed my oil pressure was steady at 320 kPa. is my guage messed up or is it perfectly fine for the oil to at that pressure and always be steady at it???

asked my father and he said it should be fine but i wanna ask others too.

thanks
davin

Shark ssn591

I'll have to convert... but my '88 runs 60psi @ idle when it is cold, 70+ psi @ speed then after warmed up 50-60 psi on the road & 35 psi +
I'll take some notes in Kpascal & let you know (I run 5W 30 Mobil 1 oil)

TIMSPEED

Under normal driving, my 87 runs at around 50psi-65psi. I dunno what that equals in kpa, but try switching it to english and see what it says. I use 10w-30 Mobil 1 (Non-Synthetic)

Shark ssn591

Timspeed.. you sure about that non-synthetic Mobil 1?
:confused: :confused: :eek: :eek: :D :D

dmalhi1

lol come on you guys aren't you all engineers ?? grab your graphing calculator and start doing conversions! its easy
ok ok i'll do em for you geez i guess i'm the only one whos an engineering student here??

1 kPa = 1000 N/m^2 = 0.145 lb/in^2

so 540 kPa = 540000 N/m^2 = 78.32 lb/in^2

hope that helps ya guys out in helping me determine why my oil pressure is high at idle according to Shark that much psi should be attained once accelerating.

Yello95

[QUOTE]lol come on you guys aren't you all engineers ?? grab your graphing calculator and start doing conversions! its easy
ok ok i'll do em for you geez i guess i'm the only one whos an engineering student here??

1 kPa = 1000 N/m^2 = 0.145 lb/in^2

so 540 kPa = 540000 N/m^2 = 78.32 lb/in^2

hope that helps ya guys out in helping me determine why my oil pressure is high at idle according to Shark that much psi should be attained once accelerating.

:rolleyes: since you are in the minority...why don't you make it easy on all of us non-engineer types and use psi? :D

scorp508

I believe that the rule of thumb is 10psi per 1000 RPM.

Yello95

...so you are saying that if I idle at 1000rpm, its ok to have 10psi oil pressure?
I think thats too low scorp...or am I wrong? maybe I'm wrong...(which thumb are you using?) :confused: :cheers:

scorp508

Yes, for a smallblock Chevy. There isn't much heat being made at 1000 RPM.

I dunno, I've heard it more than once before. I'm using both thumbs. :D

dmalhi1

yeah is that right scorp??

ok maybe you can tell me what i asked in the post??? whys my oil pressure so constant?? :D

grumpyvette

I have built and raced over a hundred engines in 35 years and what you should be looking for with a chevy v-8 is 20-35lbs minimum hot (oil at 230F-250F deg )(coolant at 165f-210f deg.) a 750-1000rpm idle and at least 10 lbs per 1000rpm example
1000rpm..20-35psi
2000rpm..30-45 psi
3000rpm..40-55psi
4000rpm..50-65 psi
5000rpm..60-75 psi (the oil pressure bypass return circuit in the oilpump,stops further increases above 75 psi and none are needed)
6000rpm..70->75 psi
7000rpm..70->75 psi
8000rpm..70->75 psi
now if you have just a little less try useing just a little thicker oil (oil should be the thinnest SYNTHETIC that gives these pressure readings)because PRESSURE is the RESISTANCE to oil-flow caused by your bearing clearances and if you have less your clearances are just a little on the large side,BTW (oil should be in the 5w-30w to 15W-40W range) and look here too.
http://www.babcox.com/editorial/us/uhs89734.htm
http://www.dorianyeager.com/oilfilterstudy1.html
http://www.micapeak.com/info/oiled.html
http://www.engr.colostate.edu/~allan...ge7/page7.html

btw this may help you find a good oilpan/pump /pickup, chevy,s can be improved upon!

and yes you can get away with 15psi at idle, and only 60 psi at 6000rpm for years in a street car but a car engine thats raced needs better pressure/flow to keep the bearings heathy and dont think that just because mr (xyz abc) runs his drag race car with only 10 psi at idle and uses a standard volume and standard pressure pump to not (WASTE HP DRIVEING THE OILPUMP) that you can too. REMEMBER HE ALSO THROWS THOSE ENGINE BEARINGS AWAY AFTER LESS THAN 1000 miles of use! you are most likely going to want them to last just a little longer than that!


[Modified by grumpyvette, 9:05 PM 12/6/2001]