wrote:


I have the cylinder from an IO-520 here that had been
detonating. The head is blown clean off the cylinder; the aluminum
fractured at the top of the cylinder threads. Things would get very
noisy, shaky, smoky and scary if that happened. Cylinder pressures go
out of sight during detonation, as do CHTs.


That sounds like preignition, not detonation. Detonation is rarly fatal
to an engine.