Posted for Walter Atkinson <walter@advancedpilot.com>:

 Craig:
 
 Thanks.  Good points.
 
 As George pointed out, a lot of the problem is the fuzzy definitions between
light, medium, and heavy detonation AND then being able to determine without
doubt that there was no pre-ignition.  One engine in particular was run about
20 hours in light detonation, about  2-3 hours in medium detonation and under
about 30 minutes of heavy detonation and upon tear-down it looked like a very
clean, normal engine.  No pot-marks, no visible ill effects whatsoever.   BUT,
we were very confident that it had never experienced pre-ignition.  This
experience is what changed our view of the dangers of detonation--as long as
CHTs are controlled and there is no pre-ignition, it's far less damaging than
we have thought.
 
 Without an engine monitor download, that's pretty hard to determine.  If
there is an engine monitor download, it's not so hard to see whether or not
there was some pre-ignition.
 
 Walter