It yielded the following interesting results: The piston rings on
every piston were broken in several places. Removed from the pistons,
the rings could be easily broken by hand, as if they were dry twigs. The
piston heads themselves (each of them) had two inch long chunks of metal
flaked off the sides of the pistons, all in the same general place on
the piston side.
Incredibly, the cylinder walls were not damaged at all, at least not
visibly, and every thing else looked fine, except for some normal wear
on the valves.
My mechanic thinks that the original source of the problem may have
been a defective turbo wastegate valve that pushed the pressure way too
high.
In any case, it was great fun looking at the impressive innards of
this engine, and I can't wait to get it back with FULL power for the
first time since I've owned it!
By the way, any suggestions as to any other work or parts replacement
(other than pistons, etc.) that should be done while it's apart?
Best, Cris