Piston and Cyl. head coatings...Yes or No Options

[SpecialK]

I just read a pretty interesting article in the new Hot Rod mag that had to do with coatings for engine internals (pistons, cyl. heads...) from a place out in CA:


http://www.techlinecoatings.com/articles/a...ation_guide.htm

They (Hot Rod) performed a test on a coated vs uncoated piston with acetylene torch, and the coated piston lasted three times longer than the uncoated piston (32 sec. vs 97 sec.) before melting a hole through it. They also recommended coating the inside of the cylinder head (particularly aluminum heads) and the face of the valves. All of these coatings can be applied at home, and cured in the oven (send the wife shopping...unless she's VERY understanding of your cause (IMG:style_emoticons/default/wink.gif) )

Any comments?

[dmenche914]

i'd be concerned about a coating that is cured in a home oven, Home ovens just do not get all that hot. parts of the head may exceed that curing temp, and thus the coating may change, or be affected at engine running temps. I would think I would want a coating that was cured at a higher temp than its service temp, that would reduce the possiblilty of the coating still changing (ie flacking, or property change) while in service. Thus I would think you'd be better off with some commercial service, that has the ability to cure the parts hotter than in a home oven. This is just my assumption, but I do have lots of experience in materials engineering.

As far as coating the cylinder fins, I read about a test, between the heat disapation of coated (painted) verses bare metal, verses old rusty, crud clogged cylinders. The bare fins had the best heat disapation, followed by the dirty ones, the painted ones came in last.

In order to stop rust, a THIN coat of high temp flat black paint may help. It might give less heat disapation than a clean bare one, however with the paint, it may not rust as fast, and thus after time, may result in better heat dissapation than a bare one that eventually gets rusty.

Any ceramic coating on the fins will no doubt reduce heat disapation, thus i would not coat the fins, except maybe very thin flat black. Same holds true for the engine case.

Gene Berg wrote a bot about paint and the case and cylinders, and the tests I read elsewhere backed up his claims.


dave