08-17-2014, 01:02 AM
(07-25-2014, 10:27 AM)Flynrider_imp Wrote:(07-25-2014, 06:52 AM)Ack-CB11_imp Wrote: 102 C = 215 F. Not very hot for oil.
Correct. For a liquid cooled auto engine (which is what API specs are concerned with) that's higher than you'd see on a typical hot day in traffic. Air cooled engines experience a wider range of operating temps, both on the high and low side, since it's the oil that carries the heat away.
Dino base oil stocks will start breaking down starting at temps above 250F. Synth base stocks are more heat resistant and will typically give you another 20 - 30 degrees above that.
Given that, I still think the trigger for the oil temp light on the CB1100 is ridiculously high. I don't even know of any synth oils that can withstand that temp without serious thermal breakdown. In fact, the procedure that is commonly used to test oils for thermal breakdown is done at 302F.
Given that, I still think the trigger for the oil temp light on the CB1100 is ridiculously high. I don't even know of any synth oils that can withstand that temp without serious thermal breakdown. In fact, the procedure that is commonly used to test oils for thermal breakdown is done at 302F.
I don't disagree with your discomfort; and I've added larger oil coolers to air cooled diesel engines. But, the manual for the engine in my truck specifies a normal oil temperature AFTER the cooler as 200°F and a maximum temperature AFTER the cooler as 260°F. Obviously, much hotter pre-cooler. This is for an engine designed in the late fifties with much poorer quality oil than we have today. Oil pressure comes up 10psi during cool down idle! Doing a search, 220°F oil temperatures are normal operation for diesels with a limit of 250°F. Maybe it isn't as big a deal as it seems.