[Richard]

I had the EXACT same problem in my NA Skymaster. Had people telling me to check baffling. I put new baffling all the way around. Pluged every hole with red RTV and still the same problem.

Got sick of having to shut off the rear engine on the taxi ways at busy airports while waiting. Enriching the mixture to cool some, then reducing power in the climb so it doesn't overheat.... yep been there.

Don't think the ceramics solved all of my problems, but helped. Some people are pretty sinical on some of these subjects. I'd suggest calling the companies themselves and doing some of the research yourself. Some non biased groups have done some pretty good studies.

A U.S. government study was done just a year or two ago suggesting using ceramic coatings on EVERYTHING in an airplane.

"The overall goal of this project is to replace the environmentally hazardous chromium treatment with the environmentally friendly ceramic coatings"

NASA and the government are experimenting with ceramic coated piston rings and cylinder liners at this time too.

More recently they are researching ceramic coatings on the pistons and valves. The study is trying to see if these coatings on the pistons will lower emissions.

Sounds like if NASA is willing to coat their pistons, exhaust, valves, and piston rings......

Do your homework, and make up you own mind.