Piston coating

RV8RIVETER · #1 03-12-2006, 08:57 PM

Hello All

I am thinking about having the pistons coated, specifically the heads. I know they do this for racing engines, but they also tear down said engine after every race.

This is a certified IO-360 in process of being rebuilt. All the parts have been inspected and certified within limits. The pistons have some head scarring, but again they were deemed OK. So, since I do not want/have to purchase new ones now, I thought it may be worth trying. I know if I do this it will no longer be "certified", but if I worried about that I wouldn't be building my own airplane.

Do any of you have any experience with engine coatings?

Thanks,

sf3543 · #2 03-12-2006, 10:17 PM

Wade
Talk to Craig at Cradin Ind. He has extensive knowledge on this subject and is an A&P. They can coat both the face of the pistons and the skirts. I would have done this on my IO-360 but assembled it prior to finding out about Cradin.

tacchi88 · #3 03-13-2006, 06:35 AM

As a race engine builder, coatings, all sorts introduced over the years actually do very little if anything to help performance. In some cases, as was ours, it usually delayed the inevitable seizures, and/or self destructions. In the end seized or self destructed any way. The damage to the engine was "minimized", but still required extensive "corrections". If cost is minimal, it "may" be a nice thing to do. In the end, carefull assembly, and good operating practices will win the day.
T88
A&P/IA/EAA Tech, Adv.
RV10 with no engine platings

RV8RIVETER · #4 04-07-2006, 01:30 PM

Well, I went ahead and had the intake tubes, piston heads/skirts, and valve covers done. Have not yet decided on the oilpan.

For anyone interested, here are a couple of pic's.

gmcjetpilot · #5 04-07-2006, 03:05 PM

http://www.eci2fly.com/pages/product...yl.aspx#piston

and

http://www.eci2fly.com/pages/product...spx#compresion

George

rv6ejguy · #6 04-07-2006, 09:02 PM

I've tried the various barrier coatings on piston crowns on several race engines. After 15-20 hours, the teardown revealed enough combustion deposits to cover the coatings which may negate some of their effects. Never saw any useful gains in power on the dyno nor measurable drop in oil temps.

I am a believer in the ceramic type, plasma/ arc sprayed coatings for exhaust components. Very impressive reductions in IR and underhood temps. Does not stay on 321 SS too well but great on cast parts like turbine housings. Had good luck with it on 304 SS turbo downpipes as well. Seems to stay on mild steel fine.

The dry film graphite/ moly coatings used by Mahle on piston skirts seems to reduce scuffing and is probably useful.

tin man · #7 04-08-2006, 11:49 AM

When I had mine done I was advised that doing the top of the piston was all that was really needed. I had my pistons , rods etc balanced before I sent the pistons in and I had to redo the pistons afterwards. In all honesty If youre not running around at full power and lean fuel setings all the time I don't think its really needed. I wouldn't do it again.
your mileage may vary
Tom
RV3

Walter Atkinson · #8 05-23-2006, 07:33 AM

I am very sketical that these coatings are worth the cost or do much to help longevity. Pistons are not the weak link in the engines. I'm also convinced that they do not add to performance. They probably don't hurt anything...... but your wallet.

The one thing I am more confident about is that coating the OUTSIDE of the exhaust is a sub-optimal idea. This holds the heat IN the metal and speeds up failure. OTOH, coating the INSIDE of the exhaust plumbing would be a very good thing--as long as none of the material flakes off and ends up in the turbine.

I'm completely unconvinced that this is a worthwhile endeavor. YMMV.

Walter Atkinson
Advanced Pilot Seminars