Peter R. wrote:
: What would be the most likely reason a cylinder in a high-time engine
: would crack, old-age or poor temperature management on a descent?

Pull power, full rich, shove nose over. Guy parked next to me has an
Archer, flies maybe 100 hours/year. Goes through at least one cylinder/year,
sometimes 2 or 3. That's his secret: at the top of descent he pulls power
to idle, goes to full rich, and shoves the nose over. Please note that
the full rich bit is required to properly master cylinder cracking. If you
leave the mixture alone until level-off you'll not have any trouble. Better
yet if you leave both the throttle and mixture alone.

You should have heard this guy going on at Oshkosh. He visited each cylinder
vendor that he's tried and they all suggested that he leave the mixture leaned.
He wasn't interested in their viewpoint, he just wanted to beat them up
about lousy quality.
--
Aaron Coolidge