Ceramic Coatings and Dry-Film Lubricants...

[Wayne 962]

Anyone have any experience with these modifications to their pistons? I'm trying to do some research on people's experiences with these mods...

-Wayne

[HawgRyder]

Wayne....
We used a ceramic coating on the tops of pistons for drag motors. It was a light beige colour and seemed to cool the chamber successfully.
If I remember correctly...the guy who did the coating used his name as the product name, I think his name was Heany...or something like that. He called his coating Heanium.
He also had coatings for the sides of pistons...with Teflon in it I think.
Also coatings for bearing surfaces and other parts.
Hope this helps.
Bob

[TimT]

funny I just asked the same question albeit in my query about twin plugs.


"plugs for twin plug conversion

I just got my heads back from being machined for twin plugs, Im wondering if I should just get 6 more of the plugs I already use? or do I need to go to another heat range?

I know I have to use less ignition advance with the twin plug set up.

Also im thinking of having the a thermal barrier applied to the combustion chambers and piston domes, would this affect the heat range of the plugs I need and willl it affect the ignition advance that I have to use.

thanks fo any help.

BTW the engine is a 2.2 with all the racy mods you would expect 10.5:1 cr rad cams, etc "


I didnt recieve many responses from the bb but i did get some informative answers privately. Ive been doing alot of web snooping about these products and procedures NASA F! and porshce use them so......

[jbailey930]

Wayne
I was considering coating my 3.3 Turbo pistons for my rebuild project. One piece of advice came from a 944 engine tuner who recommended doing it. Other advice was no way in air cooled, high compression, turbo motor. The negative point was with the coating, the heat will be trapped not dissipated. I witnessed a fresh (less than 2 hour) 930 engine blow a piston at a DE. This was a local club racer who spent $40k on the motor. P&C's coated, he was only running .8 bar boost. It was like his 3rd lap after warm ups down the main straight. The rings came flying out his exhaust. Tear down indicated too much heat. This guy had all turbo goodies: Motec, twin plugs, K29, huge intercooler, Carrera intake, etc. I opted just for dry film on the skirts. We'll see how that works.
Best

[911pcars]

By this account, the ceramic exhaust port coatings on the latest Porsche engines should cause them to overheat as well.

Not having been there, IMO, I think the 930 with the melted engine was caused by something other than using ceramic coated pistons - maybe mixture too lean, high boost, high charge temperature, detonation/preignition, insufficient fuel octane, excessive ignition advance, etc. Of all the things that overheat an engine I don't think painting something on top of a piston causes it to melt. Is it then better to have all combustion heat absorbed by the piston? (answer: no)

Coatings on engine parts for heat dispersal, reducing friction, heat containment and/or material longevity have been effectively used for years on real expensive racing engines with success. Swain Tech coatings is one name I recall. There are others.

If you're building a high compression, turbo engine, you should make appropriate modifications to ensure resultant combustion temps. and engine parts operate within safe margins - ceramic coated pistons/combustion chambers might be one such modification.

Respectfully,
Sherwood Lee
http://members.rennlist.org/911pcars

[Superman]

A friend built a 2.4L 4-cylinder engine for his 914 autocrosser project. He had many parts coated to reduce the heat problem he was certain he would encounter. That engine has run VERY well for the past three years with no heat problems.

I would agree that a melted 930 engine after only two hours did not die because of the coatings. Something else was going on there. Well, in a 930 engine, there's LOTS going on in there.

[911/914gary]

Contact Doug weaver at PS Racing in Burbank. He has done several of these engines including his own 500+ HP monster. His was featured in Excellence several years ago (wish I could remember the date).

[jbailey930]

Well, it was just one data point on the 930 engine. All other precautions were used on that puppy as I said: Motec with sensors, twin plug, compartment wide i/c and race gas. Cost was not an object. I dont know if they were factory p's or JE's. The builder and driver swear it was .8 bar. No dirty injectors, updated fuel pumps, yada yada yada. Could've the heat been created by pressure in the combustion chamber that weakened the rings?

The cost to coat is about $40/piston. No big deal there. I'd like to know for sure its safe in my motor. I'll be following this link closely.

[zotman72]

I had my rod and main bearings coated last year on my 2.4MFI rebuild. Teflon coated, but not my pistons. EBS did it

[TimT]

the thermal barriersprevent some of the heat from combustion from transfering to the head/valve/piston whatever is coated. it is claimed that the higher exhaust gas temps increase exhaust velocity, which increases scavenging

I have info from a pretty good authority who asked Porsche about the coatings on the 3.6. Porsche said just the ports, not the heads or pistons, because it messes with the combustion temps.

which confuses things further, as many (all) F1 teams, nascar and even Porsche race teams use the coatings. Perhaps its because they tear the engines down frequently, and get to see the "real" picture of what is going on in the combustion chamber...and more closely monitor a/f ratios and EGTS than we all do

I had my headers done by jet-hot, I took surface temps before and after the application of the thermal barrier and it does work on headers