🚀 go-pugleaf

** head line **

If the head's never been off, one possibility is that there's a lot
of carbon deposits built up in the combustion chambers.  This is
likely for an engine with this many miles, particularly if it burns
a lot of oil.  Two things can happen as a result of carbon buildup:
1. The deposits get so hot that they can ignite the charge before
the plug has a chance to spark, thus causing detonation.  2. The
chamber is so full of carbon that the compression ratio is actually
increased due to decreased volume (I've only seen this condition
for real in two-stroke motorcycle engines).

R.M. Mottola
Cyborg Corp.
Newton, MA.