smallblock oil pressure question - The 1947 - Present Chevrolet & GMC Truck Message Board Network

Alex Hayley · 10-29-2010, 12:02 AM

I have a new 406 that I built and installed a few months ago. It is running well but I am troubled by the oil pressure I am seeing. The oil pump is a typical Melling M55 (standard pressure and volume). The engine runs between 170 and 185 degrees. On start up I have about 70psi at idle and 80psi when driving cold. When the engine warms up I have about 45psi to 50psi when driving. When I get on it, the pressure pops up to 60psi or more. However, I have about 20psi to 25psi at idle (950 rpm) in gear and 30psi out of gear (1100 rpm). I am running 20w50 with some Lucas Oil Stabilizer. During the build I measured the main bearing clearance with plastigauge at about 0.0030" which is just on the loose side, right? Should I be concerned with the oil pressure at idle?

10-29-2010, 12:02 AM	#1
Alex Hayley Registered User Join Date: Jul 2000 Location: NC Posts: 987	smallblock oil pressure question I have a new 406 that I built and installed a few months ago. It is running well but I am troubled by the oil pressure I am seeing. The oil pump is a typical Melling M55 (standard pressure and volume). The engine runs between 170 and 185 degrees. On start up I have about 70psi at idle and 80psi when driving cold. When the engine warms up I have about 45psi to 50psi when driving. When I get on it, the pressure pops up to 60psi or more. However, I have about 20psi to 25psi at idle (950 rpm) in gear and 30psi out of gear (1100 rpm). I am running 20w50 with some Lucas Oil Stabilizer. During the build I measured the main bearing clearance with plastigauge at about 0.0030" which is just on the loose side, right? Should I be concerned with the oil pressure at idle?



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