Michael Houghton wrote:

He does offer credible arguments that the engine manufacturers
offer recommendations contrary to good engineering and operating practices.

AOPA also made that statement recently. In a recent "Airframe&Powerplant" article,
they stated "In fairness to both Lycoming and Teledyne Continental Motors, the
engine-operating instructions in POHs … appear to have been the result of marketing
decisions taking precedence over engineering recommendations."

I felt that it would have been more accurately phrased as "In fairness to both
Lycoming and Teledyne Continental Motors, their engineers are competent, but the
companies apparently lie through their teeth to get you to trash your engine and buy
a new one sooner."

George Patterson
None of us is as dumb as all of us.