Low oil pressure at idle

[BrocLuno]

Originally Posted By: Lubener
Originally Posted By: Spetz
I installed an oil pressure gauge and at idle with warm oil it sits at 15psi.

The engine is a rebuilt 6A12 Mitsubishi.
Oil pressure when cold is high (55psi or so) and when revved warm it goes to 150psi.

I understand the high pressure could be the pressure relief valve but what is the low idle pressure attributed to?

I would check the accuracy of your gauge. I doubt your reaching 150 psi.


Yeah, I'm in this camp. 15 PSI hot idle is fine with me. No work being done, engine just loafing. As long as no noise like lifter tick, no biggie.

150 PSI is way to high to do any good, and indicates that the pressure relief is not working... Should not see anything over 10PSI per 1,000 RPM, or the system is not right.

 

[ARCOgraphite]

Bruno is on it!

On the old iron V8's we built with customer requested "Racing pumps" (like a BBC pump in a SBC) that just = timing scatter and lost HP.

Do people think pumping a large volume of oil at 100 PSIg doesn't take serious power or hurt something?

More is not better here.

 

[bullwinkle]

Originally Posted By: sprite1741
The turbo 2.2 and 2.5 where Chrysler. Mitsu had a non turbo 2.5 that Chrysler sold on some models.
That was actually the 2.6 Mitsubishi, eater of timing chains and guides, very common in the earlier Dodge/Chrysler/Plymouth minivans, and also found in K cars. I knew several people that were putting timing chains in theirs pretty early, around 80-100K.

 

[Yah-Tah-Hey]

I recall seeing oil pressure spec for my 04 Camry V6 in the OEM repair manual and it is something like 15 psig/60 psig.

 

[clinebarger]

Originally Posted By: BrocLuno

Yeah, I'm in this camp. 15 PSI hot idle is fine with me. No work being done, engine just loafing. As long as no noise like lifter tick, no biggie.

150 PSI is way to high to do any good, and indicates that the pressure relief is not working... Should not see anything over 10PSI per 1,000 RPM, or the system is not right.


I don't know man, If my fresh engine had 15 PSI a hot idle.....I would pull it back out & start measuring to find out where my pressure is going. Oil pressure isn't going to get better as the engine wears in.

My L92 has a stock LS6 oil pump & makes 32 PSI at hot idle. Goes into relief at 65 PSI.

If his oil pump is actually capable of making 150 PSI at redline.......It definitely has the displacement to make better than 15 PSI at idle with correct bearing clearances.

 

[SteveSRT8]

Originally Posted By: clinebarger
If his oil pump is actually capable of making 150 PSI at redline.......It definitely has the displacement to make better than 15 PSI at idle with correct bearing clearances.




This. Sure we've had old LS engines with very low pressure at idle, but not fresh rebuilds!