I got a 455 Olds mileage unknown with Edelbrock manifold, Stock bore pistons, shim head gaskets. Took the old girl on the high way and raced a motorcycle. Oil pressure is now 7 psi idle 25psi at 2,0000 rpm.
Should I keep running it, it.s making no odd noises? I live in the Brampton area.
My son has a 350 rocket has the same oil pressure when hot had it looked at and apparently that's normal but was advised to run 15-40 Shell Rotella diesel oil for the zinc content of 1400ppm. He's running #5 heads w/64cc chambers and 2.07 intake and 168 exhaust so runs a little hotter than with the #8 heads. Drive it till it breaks Joe.
-- Edited by el toro on Thursday 24th of July 2014 12:58:30 PM
most GMs of that era run 7-10 psi hot at idle even with 15-40
The 455 Olds was a heat monster to begin with, and not known for longevity as a performance motor unless you were Mr. Mondelo, who seemed to make them survive
takes a huge rad and severe shrouding to kinda keep them cool
The general rule is 10 PSI for every 1000 RPM as a baseline minimum, so you are right about there at idle 7 to 10 PSI at what I'm going to guess is 700 to 1000 RPM in gear. At 2000 RPM you are fine at 25 PSI, but like the others have said, run a little heavier oil to keep more of it on the bearing surfaces. I think the Rotella 15w40 fleet oil has the good zinc ingredients that we need in our older flat tappet engines.
I wouldn't recommend just driving it until it breaks though, keep an eye on your pressures with the heavier oil - document your pressures at a pre-determined engine temp, measure your pressure at that same engine temp every time, as heat drastically effects oil pressures. If the pressure starts falling you may just catch it in time to save you from a crank grind or even replacement and might only have to swap out bearings without machining - saves you mucho moola!
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"If I could get back all the money I've ever spent on cars...I'd spend it ALL on cars !!!
I have built a lot of these engines for customers. One fellow 4 (for different cars.) (SS455 chev truck so he badged it and went hunting for SS454s) 56 GMC 1/2 still around after 20 odd years and running. Replaced a 4.5 caddy with a 455 for same guy and did one for his 57 Caddy two dr. Plus several for others over the years. Interesting engine. Very tough piece and virtually indestructible. That oil pressure is low. 35 Psi would be what be would expect on a stocker at 2500 RPM. 45 on a hi v pump well done motor. For racing fordy acres already covered it well. First verify the gauge. If that checks out I would be suspicious.
Not a expensive engine to do. Lots ofpower and was for years highest torque engine in production for use in cars. 440 was #2 with a mere 10 ft lbs less torque. 440s were and probably are still my specialty. 455 has similarities when building for hot rod use. As stated cooling a 455 is no accident. it takes concentration to detail.
don
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SR Dragster because old people need to have fun too!
