I have an Olds 455 engine. These engines only had 2 bolt mains and a cast crank. They are low RPM torque monsters (shifting at 5,200 RPM but making 550 Ft Lbs of torque) but they suffered from weak cranks and weak main block webbing. The cranks and bottom end would "flex" under heavy loads and RPM and wipe out main and rod bearings. In order to avoid spinning & wiping a main bearing or rod bearing, extra main & rod bearing clearance has to be built into the rebuilds.
So typically an Olds 455 rebuild will see .003" on the rods and .004 - .0045" on the mains. This allows the engine to live but requires one to run a 50 weight oil. It's common for these engines to see oil pressures of 15-20psi hot idle and 45-50psi hot cruise (180F+ oil temps).
I noticed I get better hot oil pressure with the Valvoline VR1 20w-50 oil than I do with Mobil1 15w-50. I looked up the specs:
VR1 20w-50 Viscosity Index @ 212F = 20.5
Mobil1 15w-50 Viscosity Index @ 212F = 18.0
I am considering trying Redline 10w-60 which has a Viscosity Index @ 212F = 25.9
It has the highest VI at 212F out of all the oils I found. Pennzoil 10w-60 is close with a VI @ 212F = 23.2
I would estimate maybe a 5-10psi increase in hot oil pressure with the Redline 10w-60. Any pros/cons with running that oil?
So typically an Olds 455 rebuild will see .003" on the rods and .004 - .0045" on the mains. This allows the engine to live but requires one to run a 50 weight oil. It's common for these engines to see oil pressures of 15-20psi hot idle and 45-50psi hot cruise (180F+ oil temps).
I noticed I get better hot oil pressure with the Valvoline VR1 20w-50 oil than I do with Mobil1 15w-50. I looked up the specs:
VR1 20w-50 Viscosity Index @ 212F = 20.5
Mobil1 15w-50 Viscosity Index @ 212F = 18.0
I am considering trying Redline 10w-60 which has a Viscosity Index @ 212F = 25.9
It has the highest VI at 212F out of all the oils I found. Pennzoil 10w-60 is close with a VI @ 212F = 23.2
I would estimate maybe a 5-10psi increase in hot oil pressure with the Redline 10w-60. Any pros/cons with running that oil?