Honest review of the Rotary Aviation O-ring kit
 

Hey guys,

I'm pitching this out to you all who've assembled any motors using the Rotary Aviation o-ring kit w/ the TES (teflon-encapsulated silicone) inner o-rings. Have any of you have any issues with not only assembly due to the o-rings being slightly too skinny diameter-wise but also with random, intermittent symptoms that suggest an overheated motor even though the motor has no history of it?

B

I know this is not what you are looking for, but I have been using them for quite some time on my current engine; no overheating issues at all.

i actually liked the slight tightness on assembly. if you stretch them a little bit, they fit fine, and they cling to the groove better than the stupid mazda ones that you have to be so careful with. I only have driving experience for about 15k miles on them, since I decided to blow a dowel pin, but i dont recall any problems in that period. I will be putting some of these in my 20B when I build it, but i'll probably just order them straight from mcmaster carr.

pat

I personally don't think the fitment is that great w/ them. Some you need to try to stretch in order to get them to fit in the groove, and I don't think the material takes to kindly to stretching, as it doesn't want to. I also don't feel they seal as well after looking at a motor I tore back down after 1000 miles.

This was my the last straw w/ them. I will be using Mazda inner from now on.

I have built 7 motors w/ the aviation inner rings.

Good luck collecting data.

That's been my experience. Most of the motors I built between '03 and '06 use that o-ring set. The problems I had with their o-rings were the orange, inner water jacket ones. I'm getting odd reports from a few customers here and there that are exhibiting partial symptoms of overheating for absolutely no reason whatsoever. None of the motors have overheating or water-burning history yet they are showing some of these symptoms that would say otherwise, even though it's usually only some of the symptoms instead of all of them. I discontinued using this o-ring set in mid-late '06 and have since reverted back to stock as I am beginning to believe that these inner o-rings from that RA set are not a good choice to use, even if the material and construction of the o-ring is superior (my original motivation for using them in the first place). I am also curious of the technical aspect of using a round o-ring in a square-ring land.

Anybody else have anything else to add?

B

Yeah, I used a set once in my 3-rotor when it was first assembled. For the same reasons you had used them. Once I installed the engine, added coolant, and cranked it to build oil pressure, I saw mist coming from the front rotor exhaust port. Luckily I had semi p-ports too with no intake or exhaust on, and it had collected a nice water sample in the runner. After being super pissed, I pulled, and re-assembled with stock seals. It ran great ever since. They dont really squish well at all, and the surface area being squished is very small compared to stock. I hate those damn aftermarket seals.

Subscribed.............

While I haven't built a ton of motors, I didn't have a good experience with them either. I agree that some of them didn't want to stretch to fit, and some of them were no problems. The ones that didn't want to stretch basically went back to their original shape in just a minute or so. Making it a race to mate the housings before it pulled out of the grooves. :(

I got sick of fooling with them and ordered some OEM ones as well.

That's pretty much been my frustration as well. Drove me nuts having to try and jimmy those rings to fit in the lands. I quit using them mid-late last year. Back to OEM, for me.

B

DITTO for me also BDC, had an overheat for no reason, after a hi-speed run, only 2000 miles on engine, fully tuned and conservative tune. my new engine 3mm NRS single pc, stock OEM coolant seals, GT4085 turbo. now I have a new problem,cant get the engine up to temp, runs a new 180* thermostat, and EVANS coolant. temp runs around 70-76C, seems as tho 13bs like 80-85C for best expansion. Ron

Welp, I'm no longer recommending these and I will not use them anymore.

B

We tried them back in 2001 on a few engines. They do work but it is critical that the o-ring groves are perfectly clean. However we are not a big fan of them (we got ours from Mcmaster Carr.)

yeah I had everything RA last rebuild and I have to say that the o rings where not good at all. I think since mazda has put so much time and money into R&D then why are we out buying other stuff? It's been proven to work time and time again. From now on only mazda parts for me.

Slightly off topic, but could we quit with saying that? It is obviously bogus reasoning. Mazda's R&D has nothing to do with aftermarket products. It stands to reason that the results of Mazda's R&D are in the car, so an aftermarket company starts with that, and builds on it. If you think that just because a company has done a lot of research that they cannot be wrong, or there can be no improvement on what they come up with, you should probably stop thinking at all. If that were the case, wtf is up with this wankel thing? Otto and all the car companies put a hell of a lot of R&D into the piston engine, but youre not telling everyone that a rotary was a bad idea. The wright brothers but a bunch of R&D into their flyers, but nowadays you can make a better plane in your basement in a week. The idea that just because something was extensively researched there is no way to improve on it is both laughable and sad. If thats what you believe, how do you expect anything to ever get better?

sorry, that comment is so rediculous it always hits a nerve.

Pat

This whole thread is just sad, period.
I've been using them ever since Hayes sold them (overpriced!) and then sourced them directly from McMaster.
I've never had a single problem with them and have had several cases where I had to reuse them...with zero problems.
If they were Mazda OEM, no way in hell they could've been reused.

Yes, they are not a perfect fit.
I've gotten really good at getting them to fit well.
Yes, the Mazda OEM seal is easier to install.

I fault the installation process for all the headaches indicated in all the replies.

I recommend them and use them in all my rebuilds.
Yes, I'm meticulous in cleaning the grooves.


-Ted

This is a good thread, Ted, and others will hopefully benefit from it. If you don't like it, don't read it and don't bother responding.

The McMaster-Carr o-ring (9319 K239) is a different o-ring than the one in the Rotary Aviation kit, dimensionally speaking. I'm not complaining about the McMaster-Carr o-ring; I'm complaining about the RA one. If you're making an inference that I don't clean my o-ring lands, you're way off base as I have all of my housings blasted. There aren't issue with the o-ring lands being dirty; there's issues with the o-rings they provide having random dimensions.

B

I know alot of ebay products that you must love then :rolleyes: Mazda seals have been proven to last hundreds of thousands of miles, I think RA seals are still to new and quit frankly I don't think anyone should be selling a seal for a particular application that doesn't fit correctly. I don't know, maybe your the type that likes to modify your entertainments system that holds a 24" tv to fit your 27" tv but me, I like things that are ment to fit for thier particular application. If Brian isn't the first person to see this overheating problem then I think there is a problem. I don't think I've heard of any mazda seals that have had any problems other than if someone over heats the car.

none of that has anything to do with mazda's R&D. If it is actually true that the RA seals fail more often, then sure dont use them. But that doesnt mean you should dismiss every product just because "mazda did more R&D." If you have a valid reason not to like something, thats great, but that lame shit is just a waste of time.

as far as what people should or shouldnt be selling, they can sell whatever they want. If it's worthless, people wont buy it. I belive RA states in the instructions that the seals may need to be stretched slightly to fit. And as far as reliability, if they were installed improperly or the groove wasnt cleaned enough, thats hardly their fault. There are RA water seals that have lasted just as many miles as Mazda ones. That argument is getting pretty old too. How many engines are there out there with mazda seals compared to aftermarket? And keep in mind that all those engines were perfectly clean and assembled at the factory exactly to specs, whereas many rebuilds are half shot already, and slapped together on someone's nasty garage workbench. So yeah, maybe some people get mazda seals to last 300k miles, but there are also thousands of mazda seals that have failed. If the stock coolant seals are so damn wonderful, why are all rotary owners scared shitless of overheating and blowing one?

Im not trying to say that the mcmaster seals are perfect, I just wanted to point out that the stock ones sure as hell arent, which is in fact the reason that companies supply the mcmaster ones in the first place. Maybe they are an improvement and maybe not, but you make it sound like they shouldnt even bother trying, and that's bullshit.

pat

True, but that R&D has been updated since the 7's were out. I'm not saying you're wrong, just pointing that out.

your post is invalid. BDC does top notch rebuilds and cleans his irons therougly as seen on numberous pics on his website. Also I never said not to try anything aftermarket that would just be stupid. I was talking mainly of the engine components of a rotary engine. a great deal more than half of the stuff on my car is aftermarket but the engine stuff will always be stock. I don't say this out of inexperiance as I've put a motor together using thier seals, their orings etc... and from what I saw and experianced it was sub-par when comparing them to the stock mazda parts. You can say what you want but it ain't going to change my mind.

Fist off, i wasnt trying to imply anything about BDC, i was just generalizing. I dont know anything about BDC's rebuilds and have no reason at all to say anything bad about them.

Second, youre missing my point, again. I'm not trying to say that RA seals are better than stock. I'm only taking issue with your statement about Mazda parts being better just because they did all the initial R&D. If you dont like RA as an example, heres one: how about the Kiwi-Re raplacement e-shafts? You know, the ones that can handle twice as much power than stock? Would you also dismiss that just because they arent made by mazda? Also I wonder what you have to say about 3 piece apex seals? If all this R&D makes Mazda such experts, dont you think they might have caught that one a little sooner?

The basic point I'm trying to make is that rotary design is still a relatively unrefined concept, and just because mazda was the first to produce a usable engine doesnt mean that it was a perfect one and no advances can be made. I dont much care if youre convinced or not, but you and I arent the only people who read this forum.

Anyway, we probably ought to quit polluting this thead with this argument, so I'll agree to disagree if you like.

Brian,

Are you sure about that? I had always thought that RA was just reselling the mcmaster ones?

pat

Yep they're different. The McMaster-Carr ones are ever-so-slightly thicker. I believe RA is getting their o-rings from Creavey Seal Company.

B

Well I've assembled two engines with the McMaster-Carr versions. My 91 vert has 7k on the rebuild and no coolant problems at all. I just added these seals to a friends Fd. So far so good! Maybe the extra thickness is the differance? Time will tell. I personally believe in these and will continue to use them.

I've used these on quite a few motors with no problems. I think a lot of people have a problem seating the seals in the groove and end up pinching them. The way I have done it and haven't had any problems with is that I take electrical tape and tape them down in the groove. You might have to stretch them out just slightly to get them in the goove. Once they are all taped down in the grooves stack the motor and put some tension bolts in and just snug it down. I usually let the motor sit overnight and then assemble the motor the following day. The next day you take the motor apart and the seals will sit perfectly inside the grooves. The tape holds them in place to ensure that they don't get pinched. Now remove the tape add a little hylomar and you are good to go. I've built a lot of motors with these seals and have had no problems. I tore two motors down that I used these seals in, due to other factors, and reused the seals with no problems. This is just my experience with them, which has been nothing but good so I will continue to use them. But on the other hand I like using 18awg teflon coated mil spec electrical wire for coolant seals also at $12.75 for 25ft you can't beat it. LOL.