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.

Has anyone here used the teflon o-rings from Adam heyman at RX-7 Specialties, In Calgary, Canada. And if so how has your experience gone so far.

+1 rotary avation inner seals failed on my motor. BDC replaced them with oem's and motor is fine now.

add me to the list as of now :icon_no2:
Great thread Brian.

ive hurd rumors of this before. how do you mate the ends of the wire to provide a continious seal? or is this just for the engine that only has to last one day

1

I've been using ra oring kits for about 4 yrs, never had a motor come back for overheat issues. www.rx7store.net
__________________

my RA seals failed as well.

What was the failure mode you noticed upon disassembly?

B

I built a few motors using their seals. Some were ok, others acted like a warped housing. Swapping in Mazda seals completely solved the problem.
Stopped using them around the same time I ditched their rotor-housing eating apex seals.

Mine were starting to fail/failed with only about 600 miles on them. Upon disassembly, we noticed that the teflon jacket had started to split.

Mazda OEM for me this time around.

Here are a couple pics:

Rear seal was completely split near the exhaust port, this was in a motor with less than 2000 miles on it. Other seals were showing the teflon jacket splitting like mentioned above.

Took the motor apart, replaced with mazda seals and have put 5000 miles on it without any problems. While the motor was apart, I even replaced the stock exhaust sleeves with some AL ones which would obviously put even more heat into the water near the port..

so here I am..........reading this 7 months later and wow!!
I've reused my seals 3 times. Yes, 3 times already!! They have 36,000+ miles on them and I never had a problem. I know exactly what you guys are referring to about fitment and all, but even then, I never had a problem. I think I had to stretch mine a little bit too, but I made sure it was done VERY evenly.
Weird....

i used them once, because the customer provided them for his rebuild.. they didnt fit well,but i used them anyway.. 6 months later his motor starrted showing signs of an overheated blown motor, i rebuilt it again with mazda seals.. its been fine ever since.. he was using a ron davis radiator so i know that was not the issue :)

I've used them on my motors for over 5 years with no issues. I also use them in motors I build for friends with no issues. But after reading all of this I am really hesitant to use them in someone else's motor other than mine!

Anthony

you blew the motor 3 times?

Correct! :lol2:
The first one was already blown because that's how I got the car.
The second time around (8,000 miles later), the rear rotor bearing seized onto the e. shaft. A stupid --but valuable-- mistake that I made (please don't ask) :shocking: :wallbash:
The 3rd time (@29,000 on the RA o-rings and seals--->and the pineapple aux. sleeve inserts) was due to the front aux. sleeve insert popping backwards towards the steel pin on the other end of the sleeve and knocked it out, and then the sleeve got sucked back in place and the steel pin flew right in and caused catastrophic failure (punctured the rotor).
My current build is an s4 TII block w/ s5 N/Arotating assembly. :icon_tup:

Brian.
Did you check for shrinkage/warpage on the rotor housings?
It might be that the RA seals are less tolerant of that problem than the Mazda ones especially when dealing with used housings. Even the factory o-rings depending on application meaning if it's a NA or boosted application would seal even when they are out of spec to a point. The OEM does allow a little more flexability in that department.

anyone besides me cut the black o-rings when there too big/stretched with a razor knife and use silicon? Done this quit a bit on my motors and it always worked fine.

Personally, I'll use Mazda OEM or the Pineapple o-ring kit. I havent been impressed by anything Rotary Aviation that I've gotten my hands on.

http://www.pineappleracing.com/index...PROD&ProdID=99

I personally think that RA is negligent with this little piece on their website:

"Main Bearing 1979-1991 and 4 port Renesis $22.90 In Stock
This part is for 1979-1991 Engines AND Renesis 4 port 2003 - 2006. You CAN use it on the 1993-1995 engine IF you CUT OFF THE LOCKING TAB. "

taken from (third pic down):

http://www.rotaryaviation.com/new_page_3.htm

These main bearings certainly will not cut it in an FD application, they do not have nearly enough windows in the bearing to offer sufficient lubrication, locking tab or not.

Guys I know this thread is about the RA versions but if you use the Mcmaster seals, you wont have any problems at all. No stretching needed. Regardless of the thread title, a thread like this will only miss lead people into thinking that the tephlon seals in general are no good. My engine has 18k on them and have been abused pretty badly.

Check out this amazing story.

Recently I've been just running water through my engine since I've been trying to find a coolant leak (later found at the thermostat housing). One night we had a suprise freeze that I wasn't aware of. I woke up as was like SHIT, I forgot to add coolant. Thinking the water was froze, I went to start the car and it fired right up with no unusual noises. I was like cool! So I'm on my way to work driving 70 on the interstate. As I near my exit, I start seeing a huge cloud of white smoke exit my tail pipes. I was like FUCK there went my coolant seals. All of a sudden the smoke stoped. :confused: As I exited I started noticing that my temp gauge was rising with no sign of going back to normal. I shut the car down and coasted to a safe location. I popped my hood and removed the radiator cap to find that my radiator was froze with water still in it. I looked down and noticed that the lower radiator hose had popped off. Ahhhhhhh now it all made since. With the radiator froze, there was no circulation so the un-froze water inside the engine started to boil and the pressure blew the hose off. I thought then why the white smoke? I was hoping it was just the excessive pressure inside the engine forcing the water past the coolant seals and into the combustion chamber.


I called a fello co-worker to pick me up. The only way for me to know if the engine was fine was to let the radiator thaw out and come back later. After work I returned, hooked the hose back up and put in some coolant and water. I started the car and drove away with my father following me. So far so good. The tephlon coolant seals did infact held up to all that abuse. That was a month ago and my car is still running perfectly fine with no signs of coolant seal failure. Stock coolant seals would NOT have survived this. Once they let go, they let go. The tephlons allowed the pressure to relieve through the combustion chamber up until the point it was soo great that it blew the new hose off my radiator. Based on my experience, I will NEVER go back to stock seals.

On the other hand, I did that on numerous occasions (shame shame) with stock seals as installed by Mazda 150-210k prior to my abuse!

Not only freezing the radiator, but also blowing apart the heat hose under the oil filter (and cooler on that engine). It's true, when you're driving down the road you do NOT notice it until it's too late. Fortunately, the only time that happened to me while driving, my plug wires were shoddy and the water sprayed on the wires causing a horrible misfire.

And numerous occasions of just plain running low on coolant and pegging the gauge... or running out of radiator when rallycrossing (speeds below 40mph, minute-plus long runs at near WOT most of the time, five to six runs in the space of an hour...) causing boiling-over... or the time the engine boiled over because the wires worked loose from the e-fan relay and I was standing away from where the car was idling and didn't notice until I saw coolant geysering from the overflow...

Maybe that engine just had 12 or 13 lives? Or maybe the stock seals are also PDG? (And when that engine died, it was an apex seal failure... cooling system still intact)

Then again I also have had good luck with Right Stuff silicone and 18-gauge hookup wire (yes like for radio installs etc.) ! Including overheating because I was dicking with the carb while it was idling and I forgot that I didn't have the fan installed yet... :D

PS - Every time I froze the radiator, it broke the lower tank. Wasn't always immediately apparent. Just a FYI and a heads up to watch it very closely.

The main point about my storey was how the seals survived the blowby pressure. In my situation the pressure was so great that the water was forced past the coolant seals and into the combustion chamber (causing me huge amounts of white smoke) up until the hose blew off. If stock seals would have relieved the pressure this way, they would still be leaking today. I have never heard of any situation where a stock seal leaked water like this and miraculously repaired itself. When the water seeps past that tephlon ring barrier, the combustion chamber heat/pressure will then guickly breakdown the rubber causing the seal to fail. That's my point!

MY point is that the stock seals wouldn't have leaked in the first place.

Think of it this way... pressure in the combustion chamber is on the order of hundreds of PSI. Do you think you had hundreds of PSI in your water jacket? (I'll bet you didn't...) It isn't a one-way seal, allowing pressure to flow one way but not the other. Likewise, if water leaks past, then the fact that there is a poor seal is why chamber pressure quickly breaks down the seal, not merely the presence of water.

Now, if you were to argue that the bottom half of the engine runs hotter, and so develops a tighter metal to metal seal, so maaaybe it was in fact sealed better at the bottom where the heat and combustion pressure is, vs. at the top where it's much cooler and therefore has less crush... then maybe I'll buy that. But it still shouldn't have leaked *at all*. Stock seals certainly do not. Neither do high tech solutions like hookup wire. And besides... did you have any leakage out of the TOP of the engine? The beauty of a liquid cooling system is that the liquid is necessarily everywhere and at the same static pressure. Therefore, the same pressure blowing past the wunderseal should also have blown past the outer seal. Did it?

PS - It is spelled Teflon, with an f, and a capital T because it is a proper noun, Teflon being a trade name for PTFE.

And my point is if they do they are done.




I forgot to menchion that I had stock outers. MY BAD! Yes they do a great job of sealing but they dont fail nearly as much as the inners as they aren't subjected to nearly as much heat and abuse. I know what your trying to get at about the static pressure possibly causing the water to blow past the outer seal. It didn't happen in my case as the stock seals are square. My tephlon inners (ok ok teflon just for you) are round so even through they are fairly thick, they still wont compress enough to seal with the same amount of sealing surface area as the factory square seals in the square like housing grooves. This lower surface area is the reason my teflon inners leaked the way they did under excessive pressure. Too me that leakage is fine under these severe conditions cause I know for a fact that once the stock inners allow any water to seap past them they are done.



This comming from someone who spelled underseal "wunderseal"? The "W" and "U" are no where near each other on the keyboard so you can't say it was a typing error. I'm not going to break out the dictionary (like people here seem to do all the time on miss spelled words) as I don't play that silly game. Don't tell me your also one of those who like to look for words that are spelled incorrectly to make yourself look smarter for correcting them? You do know there are a bunch of people in the world who have Phd's and don't know how to change their own tire? Please lets not turn this thread into some spelling contest. Everyone reading here knows exactly what I'm saying. It doesn't take proper spelling to prove one understands how something works.


P.S. You could have PM'ed me the spelling correction but you choose not to.

I think peejay is being sarcastic with the "wunderseal" comment. ;)

B