"Matt Barrow" wrote:
Um...leaner is cooler, Dan! 50 LOP is about a hot as you can get an
engine
without milting it down into slag.

No. Highest power, and thus greatest heat, occurs ROP. Maybe that is
what you meant to say.

I routinely run my engine 50 LOP in cruise; the CHT's stay below 380
deg. How could I get it hot enough to "melt it down into slag?"

Anyhow, "leaner is cooler" is so general as to be useless as a
guideline. It is true that cylinders will run cooler at some point LOP
than they will at some point ROP, but most carbureted engines cannot run
LOP because of poor fuel distribution. The only option in that case, if
one wishes to be sure the cylinders stay cool during break-in, is to run
well rich-of-peak.
--
Dan
C172RG at BFM