Oil Pressure Problem...

[Frank]

Ok, old Mellings pump used to put out a little too high of pressure... 90psi cold idle and 55psi hot idle pressure.... that old gauge could be off by 15psi. New Mopar unit reads 25psi cold... about 10-15 hot idle. It does get up to 50-60psi at about 4k rpms.

Is this ok???? I am nervious. She revs fast in the garage....


Frank

[turbovanman²]

That is more than adequate, spec for minimum is 4 psi hot.

[Una]

10psi per 1000rpm.. I usually get 12-13psi per 1000 in my worn out old engine (brand new oil pump), even when hot.

[BadAssPerformance]

That is more than adequate, spec for minimum is 4 psi hot.

Well that is what the idiot light comes on at but if you only got 4psi at anything above idle, you'll soon have junk.

Frank, your numbers sound ok to me for a standard tolerance motor with a few miles on it.

[Frank]

Ya well it barely has 300miles on it, and is a completely re done motor. When cruising at 2k rpms, it has about 25psi of oil pressure hot.

I still have my knock issues.... trying to figure that one out.


Frank

[BadAssPerformance]

knock as in detonation, not as in rod right?

How tight was the engine built? What all was done to it?

[Frank]

Knock as in #2 detonation, but its not detonating.... I think the cam maybe the problem.... since there is excessive noise from the head... probably off balance.

As for the engine, it is tight. Eagle H-Beam, Ross pistons, line bored, ARP, etc. The short block was assembled by a race shop.


Frank

[crazy1eye]

With Mobil 1 15w50, stock T2 oil pump...
(HOT)
Idle = 18-20psi
3k+ rpm = 58-60psi

[BadAssPerformance]

Knock as in #2 detonation, but its not detonating.... I think the cam maybe the problem.... since there is excessive noise from the head... probably off balance.

As for the engine, it is tight. Eagle H-Beam, Ross pistons, line bored, ARP, etc. The short block was assembled by a race shop.


Frank

What bearing clearance? Some race shops go loose cuz loose is supposed to make more power.

[rhubbard]

With Mobil 1 15w50, stock T2 oil pump...
(HOT)
Idle = 18-20psi
3k+ rpm = 58-60psi

I need to pickup oil soon. is that a good viscosity to use? before my pressure was almost nothing with 5-30 synthetic, except at startup where it was great.

[TurboJerry]

Sounds like loose bearing clearences to me. A HV pump on a stock engine with over 100,000 miles usually has 20-25 at hot idle if it wasen't abused it's whole life. 10 to 15 is still good though.

[rhubbard]

how high is too high of an oil pressure at idle? I know something like 75 is outrageous, but what about 50?

[puppet]

With Mobil 1 15w50, stock T2 oil pump...
(HOT)
Idle = 18-20psi
3k+ rpm = 58-60psi

Holy balls Pat ... 15w50 ? Combine that weight and Canadian weather the oil must take what, a week to get into the head? :P

[turbovanman²]

how high is too high of an oil pressure at idle? I know something like 75 is outrageous, but what about 50?

I would say 50 is too high.

[BadAssPerformance]

I would say 50 is too high.

My Z idles cold at 80. Nice and tight motor.

[turbovanman²]

My Z idles cold at 80. Nice and tight motor.

Wow, thats insane,

[Tony Hanna]

I replaced the bearings in an old Toyota pickup I used to have and fooled with the oil pump a little. It would do well over 100 psi at anything over idle when the engine was cold. It would settle back into the 80-85 psi range warmed up though.
Frank,
How fast does the oil pressure come up as you rev the engine? If it jumps up pretty quick as you come off idle then I wouldn't worry.

[BadAssPerformance]

Wow, thats insane,

LOL... not sure about insane, but it probably does rob some power. I like it tho, seems to e pretty durable (knock on wood) btw, it it is Moparboyy's old bottom end.

[rhubbard]

The reason I ask is because I would get almsot 0 pressure at idle when I had 5-30 synthetic, so I switched to 20-50 or 20-40 and it's at 50 psi cold idle. I'm not sure what it does when it gets warm though cause it hasn't ran that long and I don't know when warm is cause I need a new sending unit for my water temp.

[turbovanman²]

Sounds like you have a bearing issue. Switching to a thicker oil shows you have some loose bearings.