apex/side seal coatings?
 

has anyone thought of getting a lubricating coating on the apex seals and maybe a tbc coating on the side seals,springs and exhaust ports?
lets brain storm this. Swain can do it.
olddragger

guess not lol!
OD

Swain Coatings are wonderfull products. That said im not sure they make a proper coating suitable for apex or side seals. I can see how coating the ex ports would help.... I would go ahead and do the ex Manifold also.... but then I would worry about cooking my cat. If they did make a coating for the side and apex seals I would be all for it. I thought I had read somewhere someone had used one of there products on the rotor face. I Cannot remember where or what was said.

I would be more interested in Cermet coating everything possible

Could you imagine the exhaust heat from that one Dehacked! Ha read up sometime on the ceramic rotorys built by Mazda. fun stuff.

Some nice Inconel exhaust would help with keeping the heat out of the engine bay. Pricey yes but if you could afford cermet apex seals and cermet coating then it wouldn't be a problem. Start out with a custom double-wall 718 header I don't think heat would be much of a problem. If I had loads of money thats what I would do anyway. If the Mazda F1 team uses cermet then it has to be the way to go.

Try buying the Inconel needed for even one manifold. And I am not talking about money.

lol
the exhaust heat can be controlled in other ways
if i had my wishes i would have a rotor with a ceramic bearing instead of an apex seal!
OD

Why is buying Inconel tubing hard? There are probably plenty of companies that sell it. http://pacificalloys.com/Inconeltubing.html

Didja try?:) I hope you have a need for 20' of it at a time. At least, those were the terms we had presented to us and we were going through a guy who deals with exotic metals of all kinds in his line of work.

18' is pretty much a standard order for materials like that anyway.

If you think buying it is bad, wait until you try to cut it.

Ok back on topic..... Is there such a coating or has anyone tried to use a coating for the seals? Heck how about other surfaces anyway?

I hate to go back to it but I know that people have used cermet coating with great success on the REW. Why not on the Ren?

Side Note:
20' of tubing could make a coulpe of custom exhasts. Why not buy one length, fab it up and sell it? I would buy it if I had something turbo. How much would it really cost for a customer to purchase a straight pipe that bots to the header and goes all the way to a nice exaust tip? You would only need to sell 3 to get rid of the whole pipe. This discussion defenitely belongs in another thread so I'll stop now.

Yeah, try finding 3 customers who don't run away when you tell them the price of a properly fabbed inconel exhaust.

coatings have not made it to the renny yet--but i do believe people are starting to get more interested in them--hence the thread.
olddragger

I've someone looking at giving the apex seals a hyperlite coating (low friction, self lubricating, very hard PVD coating, normally used on milling tools), but I'm not sure on what to coat the the housings with, as being so much bigger PVD is impractical.

I emailed Swain Tech asking them for any info they may have or if they could point me to anyone that has a bit of experience using there products in the Mazda Rotary but have yet to get a response. You guys will be the first to know when/if I here something.

I would be kind of leery to use any sort of coatings on the housings as they see such high thermal loads and wear. Could they use something like piston skirt coatings?

Well, a coating on the housing would be far more beneficial than on the seals for just that reason, the problem is really on the housing we need something that has oil retention capabilities for lubrication, this rules out most of the common metal/ceramics from the industrial tooling area, pity as they have massive development behind them and are relatively cheap.
A boron nitride based coating might work but they'd need an intersticial layer underneath to get enough bond strength.

Just got a Email from Swain!!
-Well it seems it use to be common to coat the rotor faces with there TBC thermal barrier coating during the hay day of SCCA rotary racing in the 80s and early 90s.
-Also as I thought, they mentioned the use of there exhaust coating.
-This person also said he did not think they had a coating that would benefit the seals.

My question is do you think a coating to rotor faces would adversely affect the thermal considerations/longevity of the housings? Could this also have a negative effect on the seals?

I’m sure it would help keep heat out of the rotor shaft, bearings and the like. I would just worry about where SOME of that extra heat that is no longer absorbed into the rotor face could be displaced.

From the email it sounded like coating the rotor faces was at one time a popular thing to do. hmmm if it was so popular why have more people not chimed in yet? I would love to hear from someone who has done this the pros and cons.

coatings to the depressed area of the rotor face without upsetting balance would be good--also oil shedding coatings on the inside of the rotor itself would help.
I am thinking on the apex seals that the wear area of the seal may not benefit but the sides of the apex seals would--less vibration and carbon buildup? The main seals imho to benefit for a coating would be the sides.They need help.
olddragger

How would the coating affect the tolerances? In a properly remanufactured engine they are pretty short. I would prefer some seals that ae crafted from a self lubricating material (like carbon? dunno) but i don't know how long they could last.

Do you mean something like these Denny?

Paul.

Typical coating thickness for multi-layer ceramic coatings is 0.001mm to 0.006mm, shouldn't be a worry.

Paul you old cool dude! thats a start!
OD

Denny,
Have you looked at polydyn coatings?
http://www.polydyn.com/index.htm

Turblown here in Phoenix has had the polydyn coatings applied to several Rx-7s and a couple of Lamboghinis (sp?)

The Housings,Rotors,e-shaft and turbos that have had this coating applied wear much longer and the motor runs cooler water temps.

I don't see why this couldn't be applied to a side/apex seal..