Oil Change

[madmaxx]

1) determine oil pump rv set point. Rev engine while cold and identify point at which the oil pressure does not increase, this is the set point hopefully 65 t0 70 psig./
2) Use oil viscosity that generates 55-60 psig at 6K rpm.
3) If oil pump rv set at 60 psig find oil that genrates 55 psig of oil pressure at 6K rpm when hot. YOU DO NOT WANT YOUR OIL PUMP RV LIFTING WHEN ENGINE IS HOT (85c) AND PUMPING OIL BACK TO OIL PAN, YOU WANT OIL GOING TO ENGINE NOT THE OIL PAN!!!

I found Mobil 1 10W40 to be optimal or Brad Penn 15W40. With the mobil 1 I use 1/2 bottle of red line break in additive for grins. Not for camshaft protection but for roller bearings in lifters and rocker arm pivot point.

My test showed 67 psig at 100C at 6Krpm's with 20W50. It showed 61 psig at 100C at 6Krpms with Mobil 1 10W40 high mileage synthetic and it showed 55 psig at 100C with Mobil 1 10W30 high mileage. Each weight is about 5-7 psig difference.

Almsot forgot the oil ran 5C hotter with the 20W50 confirming it is too heavy for the engine.