Originally Posted by
oggers
We all know too much heat is detrimental to the engine. However, we are talking about a heat engine here so the thermodynamic efficiency increases with temperature. If the materials could take it we would run them hotter. It is always a compromise. It is too simplistic to say that colder is better. You could run at rich best power and get the same CHT as if leaned to BSFC but more power and a cooler exhaust valve. There are no free lunches.
There is this thing they call it cowl flaps i do believe not fitted to all aircraft though. Most problems with cylinder cracking is due to the use of older cylinders being reused after an o/h. Thus said they are far more susceptible to cracking due to the Parthenon known as fatigue. To be honest i cant remember the last time i had to change one on a 1st life for cracking. But more than i can count on plastic aircraft with burnt valves useing lean assist.