Lou, we are in disagreement on what goes on in a diesel vs glow engine. In a diesel engine there is a burn throughout the combustion chamber as soon as combustion temperature is reached from the added heat of compression. This gives a sharp increase of pressure on the piston. The exhaust from a diesel is expanding and cooling, not burning, gas. This is why you can stick your finger into the exhaust to see what color the oil is. So each firing cycle has a sharp blow included. This is why diesels break cranks and rods and throw prop blades in comparison to the same engines run glow. In a glow engine, the burn starts at the glow plug, and a flame front expands throughout the power stroke and out the exhaust. This is why sticking your finger in a glow exhaust will result in a burned finger. The power stroke peak in a glow is much more prolonged and smoother than in a diesel. It is a matter of universal initiation of the burn in diesel vs localized initiation in glow, rather than differences in burn characteristics of the fuel. Or so it seems to me.