Here's why a bad tune / bad gas kills motors
 

detonation

The second set of pictures is very difficult to compare to the first but it's important to note that the detonation in that case is caused by increasing the timing. It appears to me that the first set of pictures represents extreme cylinder pressures and/or poor gas (note that the plug never appears to fire).

The rapid increase in cylinder pressure at or before TDC will cause piston/rod problems very quickly.

Great post:bows:

Jerry

Awesome post! :thumbsup:

Another must read article on detonation.

link

If you have extra time on your hands you should really check out the other articles by this guy, particularly #18.:bows: Some of it only applies to aircraft but if you can get through it you will have increased your engine knowledge.:cool:

using the terms in the second article

The ping from too much timing ( the park plug firing too far before Top dead center ) ISNT detonation but its called pre ignition

Doug

You the man, Way to go Doug...:bows: