I've seen a little talk about coatings here and there, and thought it would be nice to have a thread with information about performance coatings. Which coatings are actually worth using, which don't offer much, if any, gains, etc.

For instance, I have heard of people using ceramic thermal barrier coatings on the inside of the combustion chamber, bottom of valves, and top of piston. This is supposed to hold the heat in the combustion chamber and out of the surrounding parts. I have also heard of using low friction coatings on piston skirts, bearing races, valve stems, and lifters. Heat dispersant coating is also sometimes used on parts, I myself have a head with heat dispersant coating that is supposed to pull heat out of the base metal. I can't tell you if it actually does anything

So any engine builders out there with coating experience? There are a lot to choose from and various companies that offer them (Swain, microblue, etc). What sort of actual gains could come from using performance coatings in an engine, and what is the best bang for your buck?

Ceramic works ok for a thermal barrier if you can get it to stick to the parts.

Unless its DCL done by someone that knows what there doing, everthing else is junk in my opinion(used as a friction coating).  We have tried evey coating on the market on are dyno.  We sent out parts for microblue a few times.  Could not see any power OR temp difference.  

If anyone has seen how a good DCL coating is applied, you wouldn't been messing around with at home and some professional spray on an bake friction coatings.  
But DCL is not cheap.  Some parts we do cost $1,000 each to coat.  And the gaine is vary small.

who is "we"?  and what are you applications?

So you feel that nothing other than DLC offers any noticeable gains? I feel like a dry film lubricant can't hurt on a lot of parts, just from the fact that it offers a little cushion should you have some sort of oil system failure. I feel like any part that sees oil always has an oil film between it and the next part, so a dry film lubricant coating won't do a whole lot for performance. I have dealt with a local company at work that has done some dry film lubricant coatings on some parts and I will admit, that stuff is pretty slippery.

You say the thermal barrier coatings are alright? Any real gain to coating the combustion chamber and top of piston? Some companies are claiming 5-10% power gains. I feel like 5% may be realistic, but 10% seems a bit optimistic.

I'm intrested in thermal dispersant coatings for my brake caliper and non swept area of my rotors.  Any idea of what that costs?

lazydog said:

Swain charges around $60 to coat a head with it, so I would imagine it would be a little less than that since a caliper is smaller. Probably like $40-$50 would be my guess.

I have had the best luck with this place , they are the oldest in the business.
http://www.swaintech.com/

I have never seen any difference in with ceramic style coatings in a positive way.

On highly tuned two strokes it has a HUGE negative drawback.

EVEN DLC seems to not show any real gain if the entire system is working as it should...lets think about it:  Technically there should never be metal to metal contact within your engine, period.

It's the same with transmission micro polishing - the benifits are NOT in the power gained just by doing that.

Rather by the fact that if the job is done right....you can THEN run a thinner oil often worth a little power with the same reliability as previous.

Thermal barrier coatings seem in concept to be great but I have yet to ever see a real benifit.

i have never seen a gain with any coatings,cheap to ridiculous expensive.

i have seen reduced wear but its on parts that need to replaced on a time basis any way.

valve coatings in a abusive applications how ever are critical.

Thermal barrier coatings are generally intended to prevent the loss of thermal energy to the cooling system in the hopes of having it convert to mechanical force.  In theory, this all sounds good.  It's not a new idea, as the concept was the basis for the invention of the bimetallic cylinder head (an aluminum or magnesium head with a steel or iron combustion chamber dome) in the 1940's(?).  

It has proven somewhat practical in turbocharged aircraft engines, and is useful to prevent overheating the exhaust valves and turbine fan, but heat isn't what drives a turbine, and in a normally aspirated engine, almost all of the heat that would be prevented from escaping to the cooling system simply blows out through the exhaust, accomplishing nothing.

I have not seen any measurable gains in power from coatings or surface preperations there benifits seem to be in increasing reliability .titanium has come a long way with the coatings if the right process is used .

sucmah said:

Sorry I've been away for a few days.
I can't say who I work for.  But we have a vary nice driveline dyno for testing.  
One day we had a pice of tape on the driveshaft, so we could seen when the dyno started up.  A few minutes in to the test we seen the tape fly off the shaft.  After the pull, I look at the first part of the run, and you could see a small drop in power.  That peace of tape flaping on the shaft cost .2 hp!

KJ790 said:

Your right, a dry film coating will help if you have a oil pump problem.  On a 9000 rpm V8, it's like 8 sec before the coating comes off.
Dry film on a piston skirt works if bore is on the loose side.

Thermal barrier coatings do work.  I love Calico for header coatings.  You will pick up some power from the underhood temps droping (if you rejet).
Piston tops, exhaust ports, and combustion chamber offer a vary small gain. 1 to 2%.

Id like to know more about the coating Pro Circuit Kawi uses on their fork sliders.

What about those cerimetric exhaust coatings swain does on 2t pipes. They say it makes a big difference.

They "say" it does because it "sells" their product.

The funny part about 2-stroke pipes is that they are tuned to work at a certain temperature.  The coating increases the temperature of the pipe and increases the speed of the pressure wave as a result.  You could also reduce the volume of the pipe for the same result.  So why bother with the coating?

barcode said:

A piece of tape cost you .2 hp??   I have built, and operated dynos and I just can't see a piece of tape affecting a HP reading..  Sorry I just have to call BS

.2 horsepower isn't much.   If the driveshaft were turning at 5000 rpm that would only be two tenths of a ft lb of resistance on the driveshaft to create a .2 horsepower loss.  Would it be possible for a piece of tape flapping in the wind to make a .2ftlb load on a driveshaft?  Certainly.

For more details on cryogenic treatment, Wikipedia is your friend.  Aluminum is not mentioned there, though.  It's all about steel.

From Wikipedia:
  Cryogenic hardening is a cryogenic heat treating process where the material is cooled to approximately −185 °C (−301 °F), usually using liquid nitrogen. It can have a profound effect on the mechanical properties of certain steels, provided their composition and prior heat treatment are such that they retain some austenite at room temperature. It is designed to increase the amount of martensite in the steel's crystal structure, increasing its strength and hardness, sometimes at the cost of toughness. Presently this treatment is being practiced over tool steels, high-carbon, and high-chromium steels to obtain excellent wear resistance. Recent research shows that there is precipitation of fine carbides (eta carbides) in the matrix during this treatment which imparts very high wear resistance to the steels.

The engineering world is leary about cryogenic treatment because there is no scientific backing behind the results.