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View Full Version : Oil pressure seems a lil low



Sofa King
09-27-2006, 10:10 PM
My 99 454 mag mpi runs about 5-10 psi @ idle and 35-40 psi at WOT. It isn't using an oil. Running Mobile 1 V twin 20-50. Do the big blocks run a lower oil pressure than small blocks? The engine runs like a raped ape.

Sofa King

gcarter
09-27-2006, 11:49 PM
Has it always been this pressure or has it dropped. If not, maybe a new sensor or gauge?

Rootsy
09-28-2006, 06:29 AM
"I'm givin her all she's got sir... if i giver anymore she's gonna blow... "

Donzigo
09-28-2006, 06:50 AM
Seems about right , if the engine is hot.

FYI: I would run straight 40 wt oil, non-detergent, though. A marine engine works hard all the time, whereby an auto engine loafs most of the time. The heavy oil will do a better job, IMHO.

Pismo
09-28-2006, 07:29 AM
My '96 502 Mag with Mobil 1 VTwin runs about the same pressures.

glashole
09-28-2006, 07:37 AM
check it with a mechanical indicator:wink:

Dredgeking
09-28-2006, 09:20 AM
10 psi for every 1000 rpm is the rule of thumb.

Sofa King
09-28-2006, 11:26 AM
Sounds right than, always has ran at these levels since I had my boat. I guess I was thrown cause my chevy z-71 5.3 usually gets 40-60 psi and it has 120 k on it.

Thanks All for the responses
Sofa King

RedDog
09-28-2006, 07:11 PM
Glad to hear this too because thats the way mine is after running at higher RPMs and the oil gets hot

I do want to try a synthetic and see what it does - I have always run Valvoline VR (or is it R???) straight 40W

gcarter
09-28-2006, 07:14 PM
I love 20-50 synthetic. Pressure is more consistant, even after hard running.

MOP
09-28-2006, 08:48 PM
Ken Minxguy works at Spectro Oil they blend a racing syn that beats the Harley V twin hands down, if you run a flat tappet cam it is a must. Or if you just want the very best contact him.

http://www.spectro-oils.com/ Read the independant oil comparison tests, I have the heavy duty Golden 20-50 and their gear oil.

Hotspare
09-29-2006, 09:22 PM
I think your oil pump's may be getting a little tired ..........

Case in point ,,,,,,, I had my engine out this past winter to F.O.M ...... Great time for some preventitive maintenance right, changing the oil pump was one of them ...... Was, running about the same pressure you guys have described, 15/40 psi ....... But, Installing the new pump gave me now, 40 psi at idle, and 65 at W.O.T ........... Pretty big difference I'm thinkin ......Hummmmmm Don't think the pressure's your running are hurting anything though, but do think you could be running a little higher ............ Just an observation to share ,,,,,,,,,, :)