The suggestion that keeping your oil below a given temperature means it won't break down just doesn't work with internal combustion and conventional oils. The overall crankcase oil temperature may never rise above 180 degrees, but small volumes are constantly at much higher temperatures, particularly where it splashes against the undersides of pistons and where it washes over exhaust valve rocker bosses. Extracting that extreme heat is just as much it's job as general lubrication is.
One additional thing anyone should consider before running oil a long time in an engine is molecular shear. When oil is refined, additives are given it to stabilize the molecular bonds, but they are still subject to mechanical shear. This is a much greater problem in close tolerance, high rpm engines used as aircraft and auto powerplants than for low rpm industrial diesels. The other advantage his big engine has is an industry that knows the value of $40 a gallon oil. When you have a 3 million dollar engine the fully synthetic vegetable base oils start looking cheap. RBell Did the ferry boat engine mechanics mention anything about neutralizing the acids that might form in the engine oil due to combustion processes? If so, what do they do about the salt that forms as part of the acid neutralization process?
