New build.. Oil pump is a Melling 10778.. NOT supposed the 10778C. Main bearing clearance is .028" on 1-4 .030" rear main. " rods are .0027" -12 lines to and from a Mr cool MRC CPH-775 oil cooler with the thermostat removed.. . Less than 2' of hose total. Fram HP4 Filter is mounted to a Canton 22-542 oil filter adapter ..

Low idle hot oil pressure at 750 RPM is 18 psi with 15-40 oil..at 180 degrees.. Once the RPM comes up to 900 I have 30 PSI.. at 3000 RPM I have 60 PSI..... Should I be concerned ? Had just pulled the engine apart to investigate and found nothing wrong.. Now same oil pressure readings....

Sounds pretty typical for a non-HV pump. I have a pair of motors that have very similar pressures after 1xx hrs upon disassembly all bearing surfaces were perfect. I do run 20w50 in these motors. 15w40 is a little light for to light for my style of throttling or lack there of.

Sounds OK to me.

+1

That's just it... it IS a high volume pump.....

I was going to change the oil anyway, I'll fill it with 20-50 and see what it does.... seems to run good otherwise...


good to hear.. Just freakin' out a little.. used to seeing more pressure, but then again this IS my first blower motor so clearances are a bit looser than I've had in the past...

rule of thumb is 10 PSI of oil pressure for every 1000 RPM - You have that. My 509's had higher oil pressure than my new 598 but it still had more than the rule.
I run 20/50 VR-1 Valvoline

Looser clearances = thicker oil.
Looser clearances = typically the oil psi you are seeing

I know that is an old rule of thumb but I damn sure don't want to see 7.5 lbs at 750 rpm or 10 at 1000.. 20 ish at hot idle makes me happy enough .Not wanting to argue just making a point ..[/I]

COMMON sense has to come into play.

I always tend to set up my engines with looser clearances. Some not necessarily by choice but never any issues especially with northern mi water temps and oversized coolers. Run straight 30 or 40 depending on what month were in. Although it's not uncommon anymore to rarely see water temps above 55-60.