I remember there being a thread about someone trying to make ceramic coated apex seals. Well I found some. They are made by Francesco Iannetti, and I believe are only sold through Mazda. They come in either 1 peice 2mm, 1 peice 3mm, or the more expensive 2 peice 2mm, and 2 peice 3mm. From what I understand from the article they are about $1,100 per set. Now they are very expensive but from what I am told they can withstand knock a lot longer than stock seals. They also are much lighter which means the spring pressure pushes them down further increasing heat absortion, and increasing the efficiency in sealing the combustion chamber. They also are much more resistant to wear than any other seals, they are much lighter making them more resistant to float during pressure. The single peice 3mm is good up to 45 lbs of boost! The only downside is that they are expensive. One other problem people were complaining about was the fact that with the increased height of the 3mm that it was sufficently dispersing heat. This can be avoided by running a pre-mix. (oil in fuel). I hope this helps anyone who was wondering about ceramic seals!
- Steiner

Oh yeah here is the link
http://www.scuderiaciriani.com/rx7/apex_seals.html

 

Those aren't ceramic coated, they are pure ceramic material, and you are correct that M-comp is the only distributor.

Sorry, but old news.

The ceramic coating however, is a different thread that recently took place in the "rotary performance" section. The name of that thread was Broke apex seals screwed rotors. or something like that.
https://www.rx7club.com/forum/showth...hreadid=102831

Cliff claims he can coat the housings (interior), rotors, and apex seals. I sent my housings off to be replated, & am waiting for them to come home...

 

Okay thanks for the info. Is he coating the rotor and housing with ceramics? That would be sick. With it being self lubricating and so strong. Thanks
- Steiner

 

Not arguing that these aren't much better than stock at all, but how can this be true? Seems that since the seals are at the outer circumference of the rotor centripetal force would be less on a "light" seal compared to a stocker.

 

He is only plating my housings. He says he can do rotors & apex seal too & that it greatly reduces hot spots. I'm wondering though if it will reduce the thermal conductivity between the combustion chamber & the coolant... I'll find out soon enough.

DamonB, the lighter ceramic seals are most commonly used with heavier "competition" springs. This makes up for the lower compression due to one piece design, and since the seals are self lub'ing, & wear proof you don't have any of the common problems that come with those "Comp" springs.

 

Yeah like he said, I understand that them weighing less centrifical force wouldn't pull as much as stock would. But in the kit I believe, not positive, that they have two harder springs. If they are not included in the kit I know that you can by them extra, they push harder on the seal making it contact the housing. Thanks for you intrests in this. I would imagine that coating it would reduce heat. In fact I wouldn't be surprised if it significantly reduces heat. Hey if this works it would be a great idea for everyone else to help keep temp down and increase life.
- Steiner

 

I've got a set of the ceramic seals going into my new engine, Pinapple Racing is doing the job. Hope they work out okay.

Matt

 

I'm sure they'll work great. If my budget was larger I'd be going with 1 piece 2mm Ceramics myself, but I'm going to skimp & save a little over a grand. Or maybe I should just save up a few more dollars & dump it on the ceramics

 

There's something here you guys don't seem to be realizing. If the Achilles Heel of the rotary, the apex seal, can be designed out of pure ceramic, and that it actually withstands detonation better than stock metal seals, then why not make the whole engine from ceramic? If pure ceramic is displaying better breakage strength, then make the whole motor from the same ceramic and you can throw your oil and coolant system in the trash.

Another thing about ceramic is that it has almost no significant thermal expansion and is self lubricating so the complex sealing system of the current rotary engine could be replaced with a solid trochoidal rotor that has it's tips and sides in direct contact with the working surface. Since the engine wouldn't dispense a lot of its combustion heat to a cooling system or oil, much more would be turned into usable power, especially considering the elimination of the excessive windage losses of 80 to 100psi of the current oil pressure requirements.

Since the rotor itself is a solid unit, instead of a build up of parts like the rod, piston, and pin of a piston engine, and since there is no reciprocation itself, it would seem that the crack and burst failures of past ceramic engines would be less likely in a rotary ceramic engine. Also due to the reduction in parts, especially with the elimination of water and oiling systems, the ceramic rotary would take on even greater reliability then ever before displayed. Goin by current ceramic standards I'd say a ceramic rotary 13B would go 100,000,000 miles and more with almost no mechanical wear and produce about 500hp over the current Renesis. So the added costs of the utilization of the more costly ceramic would be well worth it considering the added power and the profound life of the motor. On top of all this it'd never need an oil or coolant change, would produce far less emissions than today's unit, would be even more compact, and weigh about 100 to 150 pounds.

 

That's a great idea. I only see one problem getting someone to actually consider it and manufacture it. But hey if we could get someone to look into it and possible try making one that would be incredible.
- Steiner

 

windage??? what windage?

MWW

 

just pickin centrifical = centrifugal and that doesnt exist anyways, its only centripetal

Justin

 

uhh, if you had a solid rotor meeting so close that it touched the rotorhousing to seal it. you could chip and destroy the entire engine with a little bit of foreign debris.
And you would have to have the walls machined to perfection
There's a reason for the apex seals and springs

 

I thought ceramics crack easier than metal.

 

Garfinkle has 3mm ceramic apex seals in his car, street driven it run s good idles good , has good low end ,it will pull away at idle . no complants except high cost. they should last along time and they are said to be stronger than stock

 

Yeah. I am very intrested now in developing a new ceramic for this engine. I am taking a materials science and engineering course right now and am learning a lot about heat resistance, strength, weight, and cost. So I will see if I can find a medium between all those and then maybe in a about 5-6 years I will develop a completely ceramic apex seal. I hope.
- Steiner

 

Wait til one of those seals breaks,it's going to take out your motor and turbo at the same time!

 

"...take out the motor and turbos" ... oh, you mean just like what happens to the stock or carbon seals when they grenade?!

{ceramic evangelizing on/

Wear, reduced inertia/rotor chatter, nominal thermal expansion, increased lubicity, strength across the beam, and an "uber-cool" set of (quality assurance) x-rays with each set... Once you go ceramic, there's no going back.

/ceramic evangelizing off}

Flyin, Racin, and Buildin Rotary Beasts,
Carlos A. Iglesias
'93 RX-7 R-1 (Racin')
'95 M3 Sport (Drivin')
'01 Pathfinder SE (Towin')
http://www.the-rotary.net

 

The hurley seals are safer IMO because if they do decide to let loose they arent so hard that they damage everything in its path...

With the ceramic,thats a diff story.