I'm 99.9% sure that mazda has done all of us a big favor, and are now making a stronger factory apex seal. They are 2 piece, yes 2 piece!! just like the older 12a's and 84-85 13B. They are 2mm like usual, and slightly oversized in length. The new number is #n351-11-100C
and it replaces all of the apex seals from 86-95. Seem to be much stronger looking, and I will try to post a pic of them as soon as possible, as I just recieved a set yesterday for my rebuild. I think mazda is making them machined like the Rx-8 to cut down on machining costs, since the rx-8 uses 2 piece seals as well. Just thought I'd let you all know
Oh yeah, you cannot get the 3 piece anymore, the 2 piece # has replaced all of the 86-95 numbers.

 

interesting....i wonder if they will cost a lot more >.<

 

good to know, but I am sure there are a lot of posts covering this already.

 

why are they doing that...? They are aleady done with the 13b's...?

 

you know how much money they probably make on parts for the 7's that people still tinker with? go look at the member count for this forum :p

 

Oh yeah same cost too, another good thing!

 

I've been using them on rebuilds for almost half a year now.
All the Mazda parts have gone up in price, so they are like $60/each now.



-Ted

 

$60 each as in...per seal? As in...$360 in apex seals per rebuild??

 

Yes.
http://www.mazdatrix.com/getprice.as...m=11-C00C-N351


-Ted

 

Does anybody know what makes them stronger? Material...new design...fairy dust?
Call me skeptical but....well...ya skeptical will do.

 

buy the ones from rotary aviation they better and if you use new housings they warranty them for life

 

thats why i'm putting a v8 in my car if engine blows up .. but don't worry engine has only 8k on complete rebuild oil rings etc .. so I will still have it for a while

 

The stock OEM Mazda seals are electron beam hardened.
Through a Brinnell(?) hardness test, the new tips show about 60 hardness, but the back end of the seal only shows 40 hardness.&nbsp; This is why the stock OEM Mazda seals last a lot longer.&nbsp; This also explains why the seals wear so quickly after it has worn through the initial hardened tip.&nbsp; AS FAR AS I KNOW, *NONE* of the aftermarket apex seals are made this way.&nbsp; I know for sure, the Hurley ones are not hardened, and I have a feeling the Atkins ones are not either.&nbsp; I do not have any experience with the Rotary Aviation ones, but I do not think they are hardened like the Mazda OEM ones.&nbsp; This is why the stock OEM Mazda apex seals cost you much!&nbsp; Most of these other vendors are cutting their apex seals from blank stock with no hardening, so they break-in quick/don't do as much damage when they fail BUT they do not last longer or handle abuse (i.e. detonation) as the stock OEM Mazda units.

This has been my experience, and it has been mimic'd by others as well.

I have always recommended to purchase the stock OEM Mazda apex seals, but others can't afford them and go cheap.&nbsp; It's your call if you want the longevity or the low initial purchase price.



-Ted

 

Back from the dead. In light of recent news, what is your take on the seals now?

 

does anybody know which seals kevin landers uses? i know they are 2piece 2mm but i'm not sure if they're atkins or mazda.

 

he uses atkins.

 

I've heard problems with the new 2 piece OEM Mazda seals such as melting?

 

The ONLY reason mazda switched to two pieace seals was to cut machining costs. The three pieace seals seal better for starting and low rpm because they effectivly run zero groove clearence. I believe rotary aviations seals are heat treated the same throughout the seal. Therefore they cannot be as hard as stock seals (60 is pretty damn hard..) The reason stock seals are diferentially heat treated is to provide a super hard wear surface, and retain some durability/flexability. I'm not knocking rotary aviation seals, as they are much cheaper and much better then non heat treated aftermarket alternatives, but they will wear faster then stock (untill stock seal are passed there hardening), howmuch faster we cant even guess at untill someone like ted does hardness testing on them. (i'm going to guess youll get 50-55) I find it interesting that apex seals are heeat treated like a katana,.. someone should polish an broken one and see if they get a hamon.

 

Can one order said seals from a local Mazda dealer? or rather, where's the best place to get OEM Mazda seals?

 

what are the recent news??? please tell me..I have 5 month before a rebuild and port job...i was going to go with the OEM ones

 

There have been reports of the new mazda seals warping in certain ported turbocharged rotaries. It's too soon to have specifics as to why/how this is happening. Theres a thread on it on the other forum.

 

i remember reading that the rotary aviation seals were cryogenically treated. Anybody care to confirm?

 

I believe the news is old and about RA seals from the first production run, see this active thread:

https://www.rx7club.com/rotary-car-performance-77/rotary-aviation-seals-10-000-km-report-285884/


Its a long thread - take the time to read the whole thing before you post comments in it as RA does come to the forum and comment.

 

No, we're talking about the new mazda 2pc seals when used in turbo rotaries with porting or higher boost levels.

https://www.rx7club.com/3rd-generation-specific-1993-2002-16/who-running-new-2mm-2-piece-oem-mazda-apex-seals-328748/

 

Yep, you're right.
There's been a flurry of aftermarket apex seal development recently.
Most of the aftermarket apex seal problems have been blamed on quality control.

I believe the Hurley units are still being made the same, and the rotary community has been slowly moving away from them.

Atkins and RA have been getting the most interest, right now.

Atkins have been getting better quality control, and a number of high profile rotary builders have been getting good results.
I believe Judge Ito has been getting good results with these units with on cavaet - the seals need a slight more clearance to run.
I believe there are threads on this in here - try and do a search.

RA has release their "700% stronger" seals, but I am wary of such claims.
I think there is not enough data to support one way or another at this point.
These seals are relatively new.
So far, I think the initial, early data is promising.

I still prefer the newer 2-piece Mazda OEM apex seals, although there are reports they are melting from several, solid sources.
I'm trying to keep an eye on a couple customer cars of mine that are supposedly built under this bad combination (extra wide upside down "D" exhaust port + new Mazda 2-piece seals = melted apex seals), but so far they are running fine at around 5,000 miles per engine right now.


-Ted