[BobS]

Bigscoot
My understanding of the differences between gas and diesel engines is that the gas engine's fuel mix is set on fire by a spark, effectively a point source, and a flame front moves away from that point source in every direction, burning the mix.
A diesel's mix is set on fire by compression, with the same pressure occurring everywhere in the chamber. I believe complete simultaneous ignition goes by the label "explosion" and, combined with the higher energy of the diesel fuel, stresses the engine more.
That is why I suggested the grease powered video - it uses a point source to start the burn.