"It has nothing to do with the amount of oil in the combustion chamber, or if the engine is consuming oil or not. There's going to be oil in the upper ring zone in every properly lubricated engine. It's a question of whether the oil in the upper ring zone has a tendency to hold fuel, or not. If the fuel mixes with the oil, and the oil creates an emulsion, if you will, where it holds the fuel in the oil, that's where things can begin to go bad," says Speed.
Profound, and easily interpreted.