Rebuild + Oil Pressure?
 

I rebuilt both of my motors this spring and have been seeing some different oil pressure numbers than I had before. I have 20w50 oil and am seeing around 60lbs or higher at startup and around 40 to 50 while running. After a hard run I idle around 18 to 20lbs. If I remember right my pressures used to stay a lot more steady closer to 60lbs all the time.
The motors are GenVI and both act about the same one slightly lower than the other (could be difference in gauge). Here are the changes from last year. I am using the Clevite H series bearing and have had my pumps reliefed (anti cavitation grooves on gears). So could my volume now be higher and pressure not a issue? Did I have the wrong series bearings installed? Should I be concerned about this or is this type of pressure normal?

Remember the pressure characteristics follow both motors and yes I do have welded pickups with the brace. I am using my old pumps they only had 150 hours and looked to be in great shape. The rebuild was done because of other reasons that don't apply to pressure problems.
Thanks Scott

One other difference I can think of is the oil type I am now using regular oil (break in) used to have Mobil One 15W50 but I just can't see that making that big of a difference.

Scott,
I just my had my motor rebuilt also. My pressures are exactly like yours using the same weight oil.
My engine builder was out to the lake to tune mine and said no problem with the pressures. Are you running an oil temp. gauge. May be a good idea to install. I am running about 200* on oil temp. My lake is just too small to build any oil temp.

Paul

Scott,
I am in the process of breaking in my rebuilt Gen iv 454 Mag and see the same pressures also. Running around 60+ lb when going and warm. Only seeing 20-25lbs once warm at idle. I'm told this is fine. Running a Mellings pump with 30 weight oil.

Scott

My pressures are the same as your's, same bearings etc. After a hard run I'll idle 18-20 then as the oil cools it will come up to 35-40. Motor is 632" Merlin..

Thanks for the responses.
This will take some getting used to, I hope i am right about the volume increase. It just seems strange that it changed that much and on both motors. Scott

I'm running two new 365hps mags... one with HV melling, one with stock melling. I am still breaking in with 30 wgt. The motor with the HV pump runs at 75spi cold, 65 spi hot and at WOT... and at 40spi idling in drive after hard run. The stock melling motor runs at 75psi cold, 65psi hot at WOT and 20-25 psi idling in drive after hard run.
The rule of thumb is 10psi per 1000rpm, so if you are within that, you are running fine.

BT :cool: