OK. That's not what their Tips Publication says. Those numbers are quite a bit higher than their more recent publications.

Walter


On Apr 22, 2006, at 4:17 PM, Paul Lipps wrote:

Lycoming Spec # 2283-G for the O-320-D series says "For maximum engine life, the CHT should not exceed 475F above 75% power and 435F at 75% and below." Kas Thomas, in AIRCRAFT ENGINE OPERATING GUIDE, says "Pilots of so-called high performance aircraft are often squemish about leaving the ""balls-to-the-wall"" for more than a minute or two after takeoff, when actually there is no legitimate reason to be squemish at all (unless of course CHT or oil temperature are approaching redline). In certification testing, engines are required to spend many hours at full power, with CHT and oil temperatures a specified amount above redline."  (Emphasis his). Also, " ...cylinders will generally last longer if maintained at no more than 435 degrees." I have another source that mentions the range in my posting, but I don't have it here. When I get it, I will post it.