Posted for "Dominic V Crain" <domcrain@tpg.com.au>:

 Walter - I think your argument is accepted by most. Picked up on it about 50
 years ago.
 
 If you look at the question, it was a philosophical proposal, rather than
 just scientific.
 
 A statement proposing CHT's 385-400 F was mentioned.
 
 I know the Lycoming manual states keeping temps below 435 F is desirable for
 maximum engine life.
 
 The point is, however, what narrow temperature range is ideal.
 
 Obviously you disagree with the above statement.
 
 The drivers of the machinery we operate are heat engines. They are obviously
 inefficient if run too cold, equally as they are like to break down if run
 too hot.
 
 Therein lies an operational envelope where the heat engine is relatively
 efficient. According to Lycoming, quoting a temperature below which - etc.,
 there must lie this optimum envelope.
 
 Therefore, it becomes a philosophical debate - not scientific.
 
 Kind regards
 
 Dom