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

 Chris:
 
 Detonation (even heavy) is not audible in an airplane.  I only know of one
credible source who says he had heard it--once.  He is an FAA test pilot and
knows his stuff.  We can stand in the test cell and SEE detonation on the
computer screen and you cannot hear it at all.
 
 I suspect you experienced heavy detonation for an extended period and yes,
that can be destructive.  It is unusual to experience that without damaging a
spark plug or two and having a pre-ignition event, but it could happen.
 
 The clean cylinders are what we see from light to moderate detonation.  It
cleans things out with little to no damage.  Heck, a little light detonation
occasionally might even be a good thing!
 
 Not all cylinders will experience detonation at the same time or to the same
degree.  Some could be severe, while others are not even detonating at all.
 
 Over an extended period, even if spark plugs are not damaged and there is no
pre-ignition, you can have damage to bearings, etc.  This is possible, but
would be a little unusual as the weak link has always seemed to be the spark
plugs' ability to withstand the forces.
 
 Walter