Hi era620:
Hope you don't mind me butting in, but I've had a lot of experience with
oil-temperature control with my aircraft engine and high-performance engines in general. With that said, I like engine
oil to operate at a minimum of 180 degrees F, or about 82 degrees C. This allows the
oil in hotter areas of the engine such as the heads to reach 212 degrees F, or 100 degrees C, which boils off impurities in the oil such as the dreaded corrosion causing moisture. To do this I simply apply the old 200 mph tape over 1/2 to 2/3 of the oil cooler depending on ambient air temperature. Caution: If you're in the competition mode, don't do this because the engine should get all the cooling it can when under heavy load, so restrict it to street operation only.