RJ - you missed the key point - it is the "FREQUENCY of the oil changes" that determine the outcome. That FREQUENCY is way below the ability of the human ear to detect - it is kinda sub-sonic? But then again, I might be off my meds.

 

Pre ignition causes engine ping, that rattle or marbles people hear when it happens. The sound of the pinging/rattle is caused by a very rapid expansion of fuel mixture in the cylinder that is not a controlled burn. Your hearing a shock wave that is going 770 mph inside a 3"(?) bore of the cylinder bouncing back and forth. Sorry if I might have misled you.

 

So you're saying that the sound is actually a sonic boom? Source please, I can't seem to find any reference.

 

Sound can't be a sonic boom because sound travels at a given speed (around 750mph). A sonic boom is created by a shock wave that exceeds that given sound speed.

Fwiw. This thread sure has drifted away from the original OP question.

 

Read abnormal combustion:
https://en.wikipedia.org/wiki/Engine_knocking
This was discussed and proven when I was taking the automotive technology course at SUNY Farmingdale, NY.

 

 

Cute Blue

 

My Dad has a couple old Fats Domino records. I didn't know he recorded that one, though.

There WAS something useful in here after all...

 

Okay, just read it, but... no mention of speed of sound(or sonic boom). Maybe your rememberie is playing tricks on you.