On Wed, 25 Aug 2004 22:17:48 -0700, Richard Riley
wrote:

The #3 cyl has the piston crown pretty much gone, along with the
rings. The other pistons show significant crown damage as well. The
local A&P believes it's detonation.

I'm no expert Richard, but that kind of damage could be pre-ignition
rather than detonation.

The mags were unchanged from their original factory timing, but it
turns out they were set at 18 and 20 degrees.

One would think, with those timing settings which are conservative,
that detonation would be unlikely because they are promoting a delayed
Peak Pressure Point, which should reduce pressure and heat. It should
also reduce power a bit, but that should also mitigate against
detonation.

Corky Scott