ORIGINAL: Oil IS coolant for the engine. If the film is maintained so well, why does an engine get hotter when you lean it out? (assuming you maintain the same RPM)
And also, consider this, in a full size diesel, they maintain such a large oil reserve simply for the purpose of heat absorption.
The fuel of a glow engine has a lot to do with cooling - not as much the oil. When the fuel evaporates it absorbs heat. Also a lean mixture runs hotter in gasoline engines too.
If loss of lubrication beggins tempratures do go way up till the parts gall and seze.
The rod end carries all the load in an engine and has far less surface area than the main bushing does for the same load. The main buhsings should get just as much oil as the rod end on a front rotary valve engine since all the fuel and oil pass right there. Some engines of use an oil groove too. Crank case pressure should also be pushing a constant supply foward twards the prop. Most of my engines leak some oil out of the front bushing.
I may have to run my own low lubrication destruction tests to see what fails first......