Pickel

I just rebuilt a 5.3 with heads, cam, and “25-LSOER-HV/OR - High Volume OEM Replacement LS Oil Pump” from Texas speed. Did not do new cam or crank bearings because they looked fine. I did shim the spring in the oil pump. It has a c5 vette pan on it.

at warm idle it’s sitting around 75 psi, and when driving warm it is 95+.

is this a concern?

Che70velle

iTrader: (6)

That’s a lot of pressure. Have you changed oil filter a couple times since first start? Oil filter will entrap fine debris and assembly lube which causes pressure to rise. Filter media type affects pressure also, as well as filter size. I went from a Wix 57060 to a Wix 57502XP for more filter volume, and my pressure dropped 10 psi across the board. Just something to think about there.
The average street build with standard clearances and OEM type internals needs 20 psi at idle and 40 psi at cruise. Any more pressure is excessive and is simply eating power and heating the oil excessively. 30 years ago we were setting up race engines at 30psi idle and 100 psi up top. Nowadays, we idle them at 7psi…yes seven…and top out at 60 depending on application.
Sounds like you’ve got a LOT of oil pump there. Any more details on the build and application?

stockA4

Agreed. That is excessive oil pressure, out of curiosity, what oil are you using? If it were me, I'd be thinking about taking the shim out of that oil pump or just replacing it all together with a standard oil pump

Pickel

is it going to hurt anything? My goal is to just cruise and hotrod around, not squeeze every last hp out. So my biggest concern is reliability not performance.

RB04Av

Might explode the oil filter at startup on a cold day. Other than that, it's just wasted horsepower from having to drive the pump harder.

G Atsma

^^^^^^ This. Between the higher pressure spring and high volume pump, neither of which you need, something will blow eventually, likely the filter as said above.

01CamaroSSTx

iTrader: (3)

I'll ask some questions since nobody else has. Did you measure the bearing clearances and what weight oil are you currently running? Is this on a mechanical gauge or electronic because oil pressure senders can give off readings. If you are running a heavier oil have you tried going back to 5w30 and using a premium oil filter?

bthomas

iTrader: (1)

If you get down to the nitty gritty.. too much pump will shear the oil quicker, wear the pump out quicker thru cavitation, heat the oil more, be a source of drag that costs hp, and even cost you gas mileage.

so all in all, not just a hp loss, but also a reliability loss that you were looking for.

is yours too much?, normally I’d say no to anyone asking, but 95psi is pretty dang excessive. I’d be questioning if the relief got stuck.

Pickel

5w 20, did not check bearing clearances, it was an assembled short block that has unknown history. Cam bearing looked good and rod bearing looked good, so I assembled it with new parts for the rest of the rotating assembly. It’s an electric oil pressure sending unit, but it has been reliable on past motors.

Che70velle

iTrader: (6)

With 20w, this is even more impressive. I’m suspect of the sending unit being accurate at this point. Try a different OPS and post back with update.

Mr. Black

If I had this scenario going on, I'm going straight to a mechanical gauge and see what's doing.

grinder11

iTrader: (1)

Agreed. No engine I've ever built had 75psi@idle on 20w oil. 95psi cruising is just dangerous! Why? Because if it's at 95psi@2,000+rpm, it may be 120psi@redline. When@120psi, at WOT clocking 100+mph on a freeway onramp, or dragstrip run, this is a recipe for a funeral if/when the filter seal blows out, or the cannister does, whichever comes first. IMHO, the OP is playing with dynamite.......

Zmg00camaross

iTrader: (11)

First thing I do with either low or high oil pressure is I verify with a mechanical gauge. Sending unit could just be wonkying from removing/installing it after a rebuild.

01CamaroSSTx

iTrader: (3)

With the HV pump it would've been a good idea to open up the oil return port some on the C5 pan. I don't feel it's the reason for the high OP but it will decrease the pressure some due to an increase in flow.