Possibly just different flame rate spread causes the diferences primarily. On normal diesel the activity of buirn in the cylinder is over a long time before the piston is very far down the bore. I suspect with non petrolem products the period is much longer and translates into much smoother and less noisy power strokes. A softer primary ignition of the fuel is also going to go a long way to reduce knock,The start of the initial burn is much less dramatic but endures longer in my opinion. With gas engines the period of burn lasts a great deal longer than diesel in fact not unusual to get flames out the exhaust headers. WVO should in theory be a lot less punishing to the block. During certain operating loads and rpms there are probably some other complications that are harder for a simple guy like me to understand when wvo is either the fuel or a portion of it. I am probably wrong in what i think but I did not notice a lot of people jump on this thread so thought I would mention one of my thoughts. Still burning petro products myself. Wife hides her canola oil everytime I mention alternative fuels.