Project84

Then you ask: So have any of YOU (not my cousin's barber in Florida or some guy that you might have talked to who makes ceramic plates for Lladro or some other ambiguous association) experienced the use any of these coating in ANY OF YOUR rotary engines?

So I guess Duane and David are Rotary engine experts with all sorts of 1st hand experience in ceramic coatings and its ok for you to go get plowed and listen to them spout off quantum physics formulas so you can come here and regurgitate what you can remember about it, but we can't use our own gray matter to contemplate the same theory as the ones you discuss with your friends? How about I put it in perspective for you (in my experience, officers need to have things put into perspective once in a while so they don't loose site of the big picture).

The proven gains (through your own testements no less) of using ceramic coating on the internal engine components are next to nil. You claim that:
It helps reduce oil temps and give some (unspecified) increase efficiency (i.e. power) due to the increase thermal efficiencies.

That was from your first post.

NO coolant temp rise.
- NO balance problems to 8300 rpms.
- NO **I REPEAT** detonation EVER per my J&S SafGuard out to 18lbs of boost on STOCK turbos.
- Compression increase is LESS (at a 5-8 thousands for the coatings) than the CARBON buildup that would occur over the same interval... ANY RECOMMENDATIONS HERE?

Ok, so lets see; temp stays the same, no balance problem, no detonation, unkown amount of power increase(if any, because increased power output can be measured), yeah! I got a recommendation! How about you tell me why i should crack open a perfectly running engine that has no temp problem, no detonation and no other problems, just so I can spend my money to get the internal parts coated with some bullshit ceramic something or nother so I can put it all back together to see absolutely no change what so ever when I could spend the same amount in getting my motor ported and buying a bigger radiator to keep the engine block temps below the threshold of detonation? How much does it cost? You said it was $350 7 years ago and you get an unknown, possible no power increase, where as I just spent $250 to get Racing Beat exhaust pipes and presilencer that is proven to increase power. Speaking of Racing Beat, the plasma spray they are talking about doesn't say anything about insulating the internal components from heat to improve power or cooling efficiency. It reduces wear.

And besides that, why have people been throwing around the word detonation like it is caused only by the heat of the engine block at normal operation tempratures? It is caused by the amount of compression of a specific grade of fuel, the air/fuel ratio will increase or decrease the amount of compression required to cause detonation of that grade of fuel, as well as the temp of the engine.

This guy makes it sound like engines just detonate all the time unless you lower the temprature from the manufacturers thermostatically controlled operating temprature to some thing lower.

Again, detonation does not occur at normal operation temps, or with the correct amount of air/fuel mixture being compressed at a safe compression ratio for that air/fuel mixture.

What is a recipe for detonation, running with no oil injectors and no premix? No, this is a recipe for scratched and gouged rotor housings and apex seals because that is what the oil or premix was intended to lubricate. It has nothing to do with detonation.


carlos@the-rotary.net,
Don't worry about the definition of exothermic. Its obvious that you don't understand that a spark is not a chemical and a piston face, or rotor face isn't a chemical, though you yourself posted a definition that clearly states "A rapid, persistent chemical reaction... You see? A chemical reaction. Not chemicals compressed and ignited by an outside source of heat. The heat has to be initiated by the reaction of the chemicals in question mixing together. If you mix bleach and amonia, you get a toxic gas from the reaction. If you mix air and fuel, you get nothing. I guess its so simple its complicated.

ERAUMAZDA

Project you are right in all your comments. Yeah oil will wear down surfaces. But detonation is caused by a combustion before combustion is suppose to take place. meaning something is iginiting the air/fuel. Parts that are to hot can cause this......oil reduces this tempature. Fuel grades 93 is harder to combust than 89

wwilliam54

*yawn
your drivel tires me
this conversation is over for me

maybe again in another thread

artowar

iTrader: (1)

Anyone have any experience with the lubricant coatings? How well did it work?

Project84

I see what you are saying. The oil injected by the injectors, or the premix put in the gas tank will actually raise the flash point (so to speak) of the air/fuel mixture.
Its like how water will boil at 212F, but if you add antifreeze, you have to get it a lot hotter to boil.

BATMAN

Bump............ I am thinking about doing this.

Can we summarize in Cliff notes version the pros and cons?

I am also concern with the coating being able to take the combustion pressures.

Will that cause it to chip off?

Carlos Iglesias

iTrader: (6)

Unfortunately, there were two camps on this that did not agree on the benefits. I have personally used internal coatings and championed their benefits. The other side (Project84 & ErauMazda) disagreed.

That said, it was never questioned whether it would last. My coated rotor face did NOT chip off.

I'll be quiet now lest I stir the natives! ;-)

es

Well, I'm going to say that I agree that the oil cools the rotors reducing the hotspots that can cause detonation.

Ceramic coating can do the same thing. If the ceramic coating doesn't transfer heat you are reducing the hotspots by not allowing them to happen vs: cooling them after they happen.

Possible down side:
What if the rotor got really hot? Would the ceramic coating limit the cooling ability of the oil? Possibly, but that would mean the ceramic coating would have to get hot enough to create detonation which hasn't yet been proven to heppen. Actually our friend Carlos came here to state that even under some pretty extreme abuse he still never expierenced detonation of any kind.

Usefull info found if you are able to weed out the bickering:
Ceramic coating the rotor faces >>can<< have positive effects on reliability & power. Could even reduce the chance of hot spot related detonation by not allowing hot spots to occur vs: the typicall action of cooling them when & after they occur.

There, does everybody feel happy now or should I go buy a flame suit?

Eric.

BATMAN

I have used ceramic coating on the intake and exhaust regions as well as the turbos.

What I noticed was that the car felt as if it was just warmed up for longer intervals. I noticed more torque.

This is probably attributed to it reducing heat transfer by 20 - 35%.

Since I have done the exhaust I have noticed that there is alot less carbon deposit that stick to the surface of the ceramic coat.

I see both sides, but I feel that the coated face of the rotors would have more benefits then not.

1. It would reduce heat transer from the combustion process to the rotor

2. It smooths the surface and this helps minimize the area of carbon sticking to it.

3. The rotors are thick and I have always doubt that the 4.5 quarts or so of oil will be able to effectively cool the engine that well. Even with oil coolers the engine generates so much heat relative to it's displacement that the very hot oil will be cooled to hot at best. I think most people can agree that the thicker the metal the slower the heat transfer.

silvr94r2

iTrader: (3)

I'll toss my $.02 in to this old thread.......i haven't used ceramic coating on my rotary motors internals but it is used everywhere else. I've coated my upper and lower intake manifold,compressor housing,exhaust housing,manifold,wastegate, and quite a few other things i can't think of right now.

We've used these coatings on many many cars with great success. The most recent being the 9sec. Supra we've been building. The stock motor blew with too much nitrous which brought about the rebuild. It was done right from top to bottom without anything being coated. It lasted about a month with no overboosting or overheating. I can say that detonation brought it down along with the thin *** ring lands on the pistons. Another thing to note was the excessive chatter.

The next rebuild was underway with the same things being done as before. The only exceptions were the new pistons with a larger ring land and the use of internal coatings. The motor went back together with the same break-in period used before. The 1st thing we noticed was the absence of chatter. It was a huge difference! Once we got the car on the dyno we were supprised again. It made more power with less boost. I can't explain the exact reason why.......could've been the temp. or any number of different factors. For the most part we tried our best to keep the variables to a minimum.

We used the piston coat along with the lubricant coating on as many surfaces as we could. We've used it in many cars since along with my Banshee and my jetski's. I swear by it and will never build another motor without using it. It has done wonders for us and i'm sure it'll do wonders for whoever uses it. They just have to make sure they have a good machinest and assembler.

maxcooper

Wow, what a wild thread.

Engines work by burning a fuel and air mixture. That stuff isn't just along for the ride -- the energy released from this burning is what makes the engine go. The burning heats up the gas. The heat causes the gas to expand, which pushes on the walls of the combustion chamber. This pushing is harnessed by the mechanical arrangement of the engine (pistons or rotors) to produce motion at the output shaft. If you reduce the amount of heat that is "lost" through the rotor or piston face, you should get more power since pretty much nothing else has changed (well, that's not entirely true -- the hotter temps will increase the transfer through the uncoated combustion chamber walls, but the total loss will be less than if all the surfaces were uncoated).

I have no idea how much heat is actually lost, but just to make it more concrete imagine that the combustion gas temp is 50 degrees hotter at the end of the power stroke with the coated rotors than it was with uncoated rotors. The higher gas temps mean that there is more pressure in the combustion chamber over the course of a power stroke. Which obviously means more power, all other things being equal (and I think they are "equal enough" to support this claim).

If you disagree, state specifically what is wrong with my explanation here -- exactly which step of the explanation is wrong, and what is wrong with it.

-Max

silvr94r2

iTrader: (3)

Maxcooper: hearing it from your viewpoint brought back something that the coating guys were telling me recently. They've heard from quite a few different people that after they did the coatings (external and internal) there was a very significant gain in power and a very significant loss of "lag". I would rather refer to it as boost response but most people seem to only like to hear "lag". Anyway, the increase in heat at the end of the power stroke would have to increase boost response. That alone would be worth it's weight in gold. You could run a larger turbo and gain the top end but it would respond like a smaller unit.

Am i reading into this right or am i way off?

BATMAN

I have done ceramic coating for a few piston guys and they tell me that they notices roughly a 5% increase in HP across the board.

Temp reduction was also noticed..

TQ felt as if the engine was cold started in the morning just before the engine is fully warmed up.

fdracer

for any thermal coating to be efficient you need to coat the housings too. there is too much surface area along the housing for heat transfer that coating the rotors will net you very little gain. it's like closing your front door to keep the heat in your house, and leaving your back door and all your windows open, it doesn't do much. unfortunately all the wear along the housing would make any coating useless because it would be worn away very quickly. also whoever said it would increase the likelihood of detonation was correct. if you did have a very effective thermal insulation of the combustion space (in which rotors and housing were both coated) the combustion temps would be higher. normally this wouldn't be a problem in engines with good quench area and good flame propogation, i.e. a well design piston engine. however, this is not the case w/ rotaries, where the design does not lend it self to detonation resistance.

Carlos Iglesias

iTrader: (6)

Though I strongly disagree, I'm stayin the heck out of this one. I think I used my annual "hunt and peck" typing allowance on my original, earlier comments. I do however, look forward to someone championing my orginal contentions.

BATMAN

Having been around ceramic/thermal coatings I would think that the smooth finish would lend itself to resist carbon deposits, one of the major contributors to detonation itself.

ERAUMAZDA

I agree with both batman and fdracer.

maxcooper

When the engine is at TDC, the rotor face makes up a very large proportion of the combustion chamber's outer surface (35%?). Based on that fact, it seems like coating the rotor face could offer a significant reduction in lost heat.

-Max

BATMAN

I think it would lend to less detonation since ceramic is a poor conductor of heat and has abject heat retention properties.

There for the surface of the rotor should be cooler where I suspect is probably the hottest part of the engine from within. Sure the rotor housings are exposed to a greater area of heat, but it has better cooling propterties with the coolant passages where the rotors have just the oil and the distance of the surface of the rotor face and oil is greater.

epion2985

1-------------------

I have also been looking in to coatings and such. From what I understand the only true way to reap the most benifits is to:

-ceramic coat rotor faces
-ceramic coat housings/irons
-get ceramic apex seals

coat rotor faces/housings/irons because if only one is coated the heat will still be absorbed by the other parts and because one repells it then the load on the others will be greater.

and ceramic apex seals are a must because like said above othervise the coating will be worn off very fast.

any feedback is welcome.


2-------------------

Now with that said, lets look in to detonation. After coating more heat will be present int he combustion chamber, which means more power but also it means the mixture can detonate easier.

so when all said and done what you have is a setup that is resistant to wear and stress/heat, but if you detonate which becomes more likely then whats the boody point????

PS:
under detonation the ceramic coating may chip and come off no?

epion2985

one more thing that is bothering me is this.

The way to make more power is to create more pressure when the air/fuel mixture expands as it burns.

This is done by adding more air and more fuel.

This creates more expantion, heat/pressure.

Heat and pressure are the main causes for detonation. And you need pressure to push the rotors so the only thing you can try to bring down is heat.

So how do you make more pressure with less heat. Knowing 1. that inherently when you raise the pressure the heat raises proportionatly 2. that this is internal combustion engine so you cant really get rid of heat.

this seems to be a paradox. You need things to violently burn and expand, yet you need them to burn at very low temperatures and under high pressure.

epion2985

anyone?

Erdin

maybe water injection can help?

deadRX7Conv

Coatings will send the heat out the exhaust. There will be less heat(absorbed) in the engine. This will decrease efficiency but will allow you to run more "timing or boost or...." which will more than make up for the loss of adiabatic heat efficiency.
Plus, you'll end up with cooler oil/antifreeze and a longer lasting engine(seals won't go/housings won't warp.....).
Better make sure that your exhaust can take this heat(one reason why headers are optionally coated on the inside now besides just the normal type outside coating).

The housings are already coated. Mazda used antiwear coatings on them.
Even the T2 rotors have coatings.
The rotors had some type of teflon like coating to prevent carbon buildup.

Octane, like coatings, is a bandaid for power. We use higher octane which allows either better timing or more boost to prevent detonation. Most stock timing NAs make more power on low octane. Think of coatings as a prevention for detonation(like octane) or wear(like oil) and nothing else. Much simpler that way. The engine is more cooler since heat is sent out the exhaust. The engine is better lubed since oil doesn't go everywhere we want it too.

Every minor increase is better than none. Think of leaving the AC(summer) or heat(winter) on. It gets warmer/cooler with ONE door(front) opened faster than having BOTH doors opened.

Don't forget to coat the exhaust/intake ports and intake manifold. Anything that helps keep the intake air cool can prevent heat caused issues or be used to increase power.

epion2985

so coat the inside of the engine and the heat will go out the exaust instead of part that way and part through the walls. ok, but now there is a problem of burning out the muffler.

My question is can you ceramic coat the inside of the

exaust manifold
exaust turbo housing
downpipe
straight pipe
muffler

as to protect the car and just flush the heat out.