When you argue with an idiot, it's tough to tell the difference.

 

White2001s10: You are right on who has to prove this to you. If Dart331stroker wants to sell you coatings, he'll have to find some way to prove it to you. (I personally wouldn't bother with your attitude, though.) Just saying "all the big boys do it" is not good enough for me either, but Dart's info on lower EGT is some good info because that's a reflection of the efficiency of their entire system. For me, that's better than any single component test.

And just so you know, the military does test coatings at Wright Patterson AFB--often with the help of local schools like Wright State University, the University of Dayton, and The Ohio State University. I've had friends involved in the process for over 20 years and know a lot about it. (And no, they don't do any of that at Scott AFB--you sound like a typical know-it-all jet mech, not an engineer.) Of course they subcontract out the mass production coating work, and I'm glad they do. That's the best use of my tax dollars and yours.

There's a ton of good real world, experiential, and scientific data here if you sift through it. This is one of the most informative threads I've seen on LS1Tech. Everyone has contributed something useful to the discussion.

 

With the pistons and chambers coated how would this effect the correct Spark Plug Heat Range?

 

Good question!

Also would just coating the chambers and not the piston top negatively affect piston life? by possibly transfering more heat to the piston crown?

 

my guess would be you could go 1-2 steps up in heat range. either that or no effect at all.

 

Though I personally observe the merits of thermal coatings I commend white2001s10 for keeping his cool during eight pages of flames against himself. He wants data, not hearsay, and no one has provided it to him.

 

I was reading the whole thread up to when people started arguing about who has to prove what, so if this question was answered already, forgive me.

Personnally, I believe that coatings would work as the logic is there. I just had 2 questions.
1. When coating the piston crowns, combustion chambers and valves, will this decrease the cc of the chamber? is the coating thick enough to make a difference or not?

2. Are there any coatings that could be used on the sidewalls of the cylinders themselves?

thanks again in advance

 

The coating for the Piston Top, Chambers and Valves is less then .001, will not make much if any difference.

 

Why would anyone spend hundreds of thousands of dollars building engines, testing components, coatings, tuning , etc. and then give away all the results of the test, giving up the competitive edge that testing achieved?

For everyone that doesn't believe and continues to seek proof, please re-read all eight pages and notice how many times the words FREE information appears. Help was offered so that anyone could try to reproduce the test & results to their satisfaction.

It does't matter if you are a scientist, an engine builder or a backyard mechanic. If you are class racing and held to tight tolerances thoughout the engine, you would never reveal exactly how you achieved results that gave a superior performance. Racers are friendly people, but they race to win.

Sure there is a lot of money in a racecar, but anyone who believes there is anything in a racecar that doesn't have to be there to win is kidding themselves. Roush is an excellent example - they've easily built enough engines and developed a procedure to obtain repeatable results (much lower than 5-8hp) from one engine to another. If repeated tests showed that non-coated engines performed equally as well as the coated ones, they would leave it out!

I'm sure a race team would proudly proclaim any paying sponsors product on the side of the car, but do you think every square inch of Jeff Gordon's chassis and car body are 'exclusively' covered with DuPont finishes?

 

If your post was intended to me, I just wanted to clear it up.
I my response (post #148) to the coating being about .001 thick and not making much difference, I am referring to change in the cc of the chamber, the question asked in post #147.

I do believe that the coating is a benefit and I am using coating in my current engine build.

Bob

 

Nikasil is the only thing I've ever heard of. Other than rubbing down the walls with an assembly graphite or something.

 

Dart331Stroker, I want to compliment you on your patience. Obviously, coating various parts works. Obviously, some would rather argue and project pedantic discussions of "science" than real world results. My hat's off to you for holding your temper and responding in a civil manner. I hope you'll be around for other discussions.

Olen Goodwin

 

Bob,

My post was not directed at you, I just happened to respond after your post once I finished reading all the previous posts. It was for those who are demanding the scientific proof as well as the test methods so that they can see the results that they want before accepting that this stuff works. I'm not arguing for or against at this point, as my car is all stock internally. I'd be better off optimizing airflow into and out of the engine long before the coatings became a worthwhile investment for me.

I'm mainly just teching in here because I may build a shortblock someday, and I would definitley be interested in TBC and anti-friction coatings then. Less heat transfered to the engine, and therefore the cooling system, is more heat pushing on pistons.

 

A few general Qs, if anyone has the time:

Can one coat nikasil surfaces with ceramic compound?

Can ceramic be used in place of nikasil on a fresh, sleeveless aluminum block?

I've read that the high-sulfur content of imported, ie, cheap, street fuels are hurting nikasil coatings (BMW V8s and others): I just called four Porsche dealers in NYMetro -- they haven't had any problems, know of no related Factory Notices. Assuming that some nikasil surfaces are being affected by these fuels, does anyone know which nikasil process can handle the sulfur? What, if anything, is the downside of the sulfur-resistant nikasil coatings?

(The engine I'm researching will run on street fuel.)

Thanks in advance.

 

It is nikasil that is the coating. Used to coat the bores on cast iron blocks, iron liners or aluminum blocks.
Ceramic liners are used in cup engines according to this thread. http://speedtalk.com/forum/viewtopic.php?t=519 Nikasil can also be used to coat Metal Matrix Composite liners http://www.perfectbore.com/performan...nderliners.htm
BMW and Jaguar had problems with nikasil. Porsche with more years experience did not have problems with it. http://www.lnengineering.com/type4.html

 

Thanks, JCR --

From what I've read, confirmed with a scan of the links you were kind enough to provide, is that nikasil is used to control friction, while the coatings traditionally referred to as "ceramic" are meant to keep the heat in the cylinder, increasing some aspect of performance and protecting some components by reducing the amount of heat they're exposed to.

What I'm wondering is if one needs to apply both -- nikasil and "ceramic" -- to both reduce friction enough to go sleeveless and to keep as much heat as possible in the cylinder.

Perhaps there are other options.

EDIT: I don't like the term "control friction" in the first paragraph, as it doesn't make clear that nikasil resists damage by being harder than the surface it's protecting.

 

Good discussion even thought I get the impression that no amount of empirical data would satisfy everyone.

Like many, I find it hard to believe what I haven’t seen personally or heard from an impeccable source. In my current life as a Test Engineer in the Missile Defense industry I find myself querying many of the resources I have available during the day to satisfy many questions outside of the aerospace business. If the answers aren’t readily available I find myself proving the worth of some products myself.

I can't speak for all of the other coatings, but I had tested Techlines CBX coating 8 years ago. It’s advertised as a thermal barrier coating for pistons in nitrous and other high temperature applications. I'm sure the other coating companies use effective materials also. For my test, CBX was applied on 2 piston domes according to Tech Lines application instructions. Speed Pro flat top forged pistons were used in the test. 2 were tested as received. The first test that was conducted was a heat soak-test, Time vs. Temp. TC probes placed on the center/back side of each piston dome. Data was acquired at 1000 Hz sampling frequency. The heat source was an Oxy-Acetylene torch set 2" from center of untreated piston. The test was conducted over a 5 minute period. A CBX coated piston was tested immediately following the un-treated piston. This was followed by another untreated piston, which was followed by another coated piston. Much to our surprise when the TC data was examined, both coated and un-coated pistons followed the same temperature rise vs. time. Thinking about it, with a coating penetration depth of approximately 0.001”(Thermal resistance is very small because of lack of thickness) it is no surprise that they were a virtual layover on all four pistons.

The last test was a destructive test and the oxygen was turned up on the Oxy-Acetylene torch. The flame tip was once again placed two inches from the top of the un-coated piston as the timer was started. The first observation on the un-coated piston was the heat zone was red hot and half the diameter of the coated piston which was tested later. 2 min, 20 seconds into the test of the un-coated piston the top melted through. The coated piston was tested next with a burn through time of 4 minutes 52 seconds. It’s heat zone was duller red in color and twice the size (½ dollar size vs. dime). The other two pistons were tested to check repeatability and were found to be within two seconds of the first two pistons melt through times.

I know the sample size is small, but the test was on my dime and I’m confident it would repeat within a statistically significant sample size given the time and resources. Another interesting observation was the coated piston maintained it’s surface shape until the point of melt through when the back side of the piston failed before the top. The un-coated piston started eroding at the point of flame contact and the final burn though hole was much smaller.

Racing nitrous and blown engines in drag racing using this form of coating has yielded qualitative results that support the test findings. If you need a little extra margin at the end of the track to keep your pistons from burning though this type of coating could save you some heart burn.

 

Porshce Cramic coats alot of their turbo exhaust ports . If its good enough for them its good enogh for me . As soon as I can afford it I am going to get my heads done at Performancekote in Orlando they did my headers and they came out awesome . The guy there said he was going to advertize on here and give a discount , I think their website is performancekote.com

 

I keep reading that people that take apart 924/944/928/968 blocks never -- NEVER! -- see any sign of the nikasil damage -- no scratches, dark spots, etc.

I'm still wondering Re "ceramic" in conjunction with nikasil or other protective coatings.

 

TT632,

Thanks for sharing your [expensive] data.

There seems to be a plethora of data in support of these finishes. It's up to each of us to evaluate them for our application and budget.

Me?

I love tech too much to bypass something like this!