Seems that this is an area that domestic guys seem to have greater knowledge than us "import" folks based on the search results I have seen.

I took interest in this topic when I decided to have my next engine ceramic coated on the rotor face and to have the outside of the engine coated in thermal dissipation materials.

Since no one has actually viewed the common points of detonation and knocking in an engine it would be fair to assume that the rotors are the culprit since they seem to have the least amount of cooling efficiencies.

This being said, it might be a good idea to coat the rotor face so that it serves 2 purposes: 1) smoother surface that minimizes carbon from sticking to it, 2) reduce heat transfer to the rotor itself.

High-tech coatings for engine and driveline parts have been around for decades. Early coatings sometimes deserved the reputation for poor durability and ineffectiveness, but when u consider most of the top Winston Cup and Top Fuel teams (and even a few OEM's) use several types of coatings in their engines today, they've proven their performance benefits.

There are three main types of coatings, and their names define their functions; thermal-barrier, heat dispersion and low-friction.

Thermal-Barrier coatings help to retain heat, Heat-Dissipating coatings help to move heat away and Low-Friction coatings help to reduce power-robbing heat friction.

Heat makes power, the more heat u can generate, the more power an engine will produce. Unfortunately, the internal combustion engine is inefficient when it comes to managing heat, using only about 20 percent of the heat energy created in the combustion chamber. Most of the heat escapes through the exhaust system or is absorbed into the engine and removed by the cooling system. Obviously u can't eliminate the exhaust system and the cooling system is mandatory.

The purpose of the thermal barrier coatings is to effectively contain and manage the heat that is created when combustion occurs, this optimizes the efficiency of combustion.

Here is a link that further explains the different coatings, their features and benefits, and illutrations along with references:

http://www.hotrod.com/techarticles/51120/

This should answer everyone's questions.

 

coating the rotor face might be bad, as the heat that is going into the rotor has to go somewhere, and if it cant go into the rotor then its gonna go into the coolant?

and if you put the heat dissipation stuff on the outside of the motor, its gonna fry evrything in the engine bay that much faster, no?

 

I've always been a big believer as far as coatings go. I consider them a mandatory part of my rotary build once it comes to that.

Also, another good place for a thermal barrier might be the inside of the exhaust sleeves. That combined with with a coated header should give at least a little bump to turbo spool, not to mention a cooler bay. There's the usual suspects for low friction coatings, too. Stationary gears, rotor gears, bearings, etc.

Oh yeah, j9fd3s. Your correct in saying that where the heat is going is an issue and you've gotta take it into account. When coating the rotor, that means that more heat will be going into the charge, coolant system, and exhaust gases. Subsequently, you'll prolly see a little warmer coolant and exhaust gasses, as well as an across the board torque increase and slightly cooler oil (from less heat being absorbed at the rotor). Thats how I see it anyway.

EDIT: Hmmmm, I wonder..... Would it be a good idea to coat the inside of spark plug holes? Not so it interfered with the threads or cooling of the plug, but would a thermal barrier be good in the little port? It may reduce the chances of stress related cracking.

 

I just read in another thread that pineapple coats the sparkplug holes on their 5yr warranty engines. So the idea's got merit.....

 

I would like to know...
How could you put a "thermo" coating on the threads and have that NOT interfere with the thermal conductivity of the spark plugs body itself???



-Ted

 

I would like to know...
How much these procedures cost???

 

Yeh, whats the general cost for most of these operations, say, how much has one spent on getting a rotor done?

 

Since the coated rotor is going to deflect 25% - 35% of the heat, it will certainly charge the coolant as a result. Of course the exhaust will be hotter as well.

I have an upgraded radiator, Koyo that should be suffice to handle that.

By coating the rotors, this helps take the load off the oil coolers that, IMHO which are less efficient than water in cooling efficiencies (that is why Porsche started to water cool their 911's).

Furthermore, this process should add TQ & HP since it raises the thermal efficiencies per combustion event.

www.swaintech.com charges $150 per rotor according to their site. They coat just the rotor face.

As soon as I have my engine apart, I'll have my local guy give me his price.

Just imagine coupling ceramic coated rotors and the external thermal dissipation coating with KDR anti-detonation device. That should easily take Sequentials well into the large single turbo territories as far as power is concern per PSI.

More on this later as this project develops with pictures as it unfolds........

 

I never heard of coating the threads.

Doesn't the plugs need direct metal contact to the engine block for proper ground?

 

its not the coolant temps per say but the rotor housing temps that are gonna go up, and seeing as how they are already over worked.....

porsche switched to water cooling because its nearly impossible to cool an engine consistently with a fan

 

Yeah, I wasn't talking about coating the threads. That would mess with the ground and cooling. I was talking about just the hole up near the housing face, around the electrode area.

 

What about widening the cooling passages in the rotor housings?

I think Racing Beat does that with some good results.

Labor intensive however.

My best guesstimate is that most of the heat would escape via exhaust and the Koyo can handle the rest.

Again, when i spoke to the technician at Swain Tech, they said there were only benefits and no issues whatsoever on rotary applications.

 

they can't produce any receipts that prove that they have the procedure done....

they do mill out the holes so you don't have to use a thin wall socket, but i think that's the extent

 

also, you want the rotors to transfer heat, the rotors are oil cooled...if they do not transfer heat, then i don't see how that would benefit the design

 

The rotors benefit because the coating is only on the face thats exposed to the combustion chamber, which prevents heat from getting into the rotors in the first place. If you were to coat the insides then that would trap heat in the metal, which may be what your envisioning.

 

CyberNinja is right.

A few days ago I spoke with Skip at KDR.

Skip used to work for Mazda and he told me that when the rotor's get too hot and the oil can't cool it enough it would created sunken areas on the rotor face that was mistaken for detonation points.

So that is why coating the rotor face makes sense to me.

 

the rotors are oil cooled, they cool something like 20% of the engine that way, if you block that the 20% has to go into the exhaust and the coolant. well those are already too hot....

 

Just a thought, but if it's possible to have a heat-dissipating coating put on to the water jackets, and also upgrade the radiator/coolant system shouldn't that help cure that problem? If the water jackets can't be done or even if they can, maybe have the outside of the block coated with heat-dissipating material...

Everytime a thread comes up on varous forums about the best apex seals, a lot tend to say ceramic are the best, but obviosly expensive as hell.
What about just taking a stock replacement (or your favorite non-ceramic apex seal anyway) and having it ceramic coated? ceramic is suppost to be lower friction along with better heat resistance right? Maybe even go so far as to shotpeen and ceramic coat them? may not be cheap if your just doing the apex seals but if you get the rotor faces done I'm sure it wouldn't be bad thing to throw in.

Dustin

 

I'm thinking about the low-friction coating.

Where could we put that where it wouldnt be destroyed?

How bout the side housings? Would it last on the rotor housings themselves?

 

side housings

 

Somehow I find this very hard to believe...
I sounds like someone trying to shift the blame off bad tuning and detonation.

-Ted

 

Didn't Mr. Wankel write a fairly large article about using ceramic coatings on rotary engines?

I really like the idea of using Dry Film Lubricants on rotor bearings, but I wonder if they would last on the apex seals and side seals.

The Thermal Berrier Coating would keep more heat in the Combustion Chamber, giving slightly more peak power? But would also not let the rotors kewl the engine as well, and make the radiator and exhaust system work more.
Using a themal dissipation coating would take heat away from the combustion chamber, taking away a little bit of power? It would take some heat away from the water cooling system, but add more to the oil cooling system?

 

This is not a substitute for bad tuning, but due to it's what it may offer, the coatings could very well allow greater tuning thresholds to be pushed, such as a slightly leaner ratio.

Sure, it does retain slithly more heat in the combustion chamber, but the thermal dissipation coating is on the external side where it's not directly involved with the combustion event and this is heat that has already been cycled and needs to be removed.

 

I concur. I'm seriously thinking about doing this on my next biuld.

 

not if i beat u to it.