Jaba
Ok let me say that what works on the computer is not always what happens in real life.
Simply put there are a lot of differences between manufactures, what material they made of comp ratios ignition timing etc etc etc. Detonation is always harmful period. Just because it didn't break now doesn't mean its not going to break. Stress now may not show now but will. The most harmful thing is that force is placed onto the big end bearing. This is the part that generally fails first.
As I recall the ATSB said it was pre ignition due to the lead and carbon on the piston head. Lyc rejected this totally. You said that was not overly lean well it must have been. full power full rich.
You said that fuel dosnt have a cooling affect. MMMM so how come when I pull the red knob back the egt cht rise, ?
At the end of the day I see the results. Ill just keep changing them out. Im Happy to do that.
Cheers always happy to learn