A “straight 10”. Now I’ve seen everything!
Wonder what the firing order on that son of a gun is.
It can be caused by both, actually. Retarding timing will help if it’s being caused by “spark happening too soon.” Spontaneous detonation requires different steps, usually the cheapest is to use a higher grade of gas.
Here’s the whole story:
John Deere 2 cylinders set the crank throws at 180* which meant that the engine had 2 power strokes on one revolution and none on the next. It would POP twice and then pause, then POP twice and pause. Harley Davidson’s odd sound is from a similar situation, they put both rods on a common throw and spaced the cylinders at 45# and the engine fires alternating between 315* and 405*.