I originally posted this in the Old School And Other Rotary section but thought I'd post it here as well, for anyone interested in GSL-SE engine rebuilds. I'm having my GSL-SE -based 13B rebuilt and was supposed to get stock Mazda 3mm apex seals. It's a NA street motor and I don't want or need harder/stronger seals, especially with concerns of housing wear. My '84 GSL-SE housings are still in very good shape and my builder recommends OE seals for all NA engines. From the original thread -

So my engine builder called to tell me that 3mm/13B Apex Seals are "On back-order indefinitely" according to his Mazda dealer. I looked up Atkins site and they show 970 sets in stock, but when I called they told me the same thing; "Back-ordered indefinitely. Not dead yet, but nobody can get them".

I realize this only affects 74-85 13B's so it's a fairly small market for Mazda (compared to all the 2mm 13B Apex Seal engines '86+) but it's affecting ME right now, and everybody else reading this who has an older engine to rebuild. If Mazda really is stopping production on these then the 12A seals will be next.

My builder is going to use either I-Rotary (*) or Goopy seals and tells me I'll have to double the amount of pre-mix I've been using. If I put the OMP back on I'll still need to pre-mix so the harder seals don't wear the housings prematurely. My car isn't subject to emissions testing because I have a PA "Classic Car" registration, but anyone who still has their emissions equipment and is subject to yearly sniffer tests could be affected by the smokey exhaust and possible cat. converter fouling.

*I-Rotary hasn't made 3mm/13B seals in several years, but MazdaTrix shows them in stock. We're going to call them when they open today and use those if they're really in stock. My builder says they're a little easier on housings than the Goopy's (my engine's a NA street motor).

 

N304-11-300A is out?

Did the turbo people quit milling their rotors for 3mm seals?

I don't know if opinions have changed but Atkins seals have been recommended for stock rebuilds.
I put 70k miles on a set before my 13B spun a bearing, I used an RX-8 rear gear without knowing about the offset oil port.

 

Yep, N304-11-300A is what we were after but they're not available. When I talked to Atkins (Mr. Atkins?) he had a long explanation that I didn't fully follow. Something about before 2020 Mazda would announce when a product was being discontinued and make one final production run. But since 2020 they just sell out and then list them as "Back-ordered" forever, just in case they decide to make another run some day. So they aren't officially NLA, but good luck getting them.

I'm not trying to start another Apex Seal thread, but since I wanted the OE seals and they aren't available, I thought I'd bitch.

 

yeah, they don't work as well as the 2mm stuff

two things, Mazda never announces anything that actually happens... two; its become really common that Mazda USA stops ordering stuff, but its available in Japan still.

Mazda USA shows a date of June 14th as an ETA, they probably won't meet it. there are tons of parts on backorder right now

Mazda Japan seems to have figured out that if they have stuff people will buy it, but Mazda USA hasn't.

 

Thanks for the info. I've been waiting on this rebuild for months ("2 to 3 week turn-around" they said.... yeah right). They were supposed to stack it this week but no Apex Seals, so... I can either use a stronger/harder seal and get the motor back early next week, or... leave it with them indefinitely and wait on a low-volume-selling part to come back into production.

I think I better buy stock in Peak 2-stroke oil. Im going to burn a lot of it.

 

I've seen many apex seal producer's websites discouraging this. The 2mm seals seem to be plenty strong, and changing to 3mm seals actually induces a measurable amount of extra friction by that extra 1mm. The modern thinking seems to be (from what I read) is that bad tuning / detonation is the failure point ; not the Apex seals. IE: stock Mazda seals can hold 600 whp as long as the timing/tuning is good.

I'm not building a drag motor. I'll be happy with 200hp in this car. I want to blast up n down the mountain roads where I live (*) and red-light race some Subies and Audi 2.0T cars. It's just a classic street/sports car build.

*I want to go to the DGRR some day, but watching videos doesn't impress me much. Those roads look tame/lame compared to all the mountain and river roads we grow up racing in SE PA.

 

My builder (I.R.Performance) found someone with OE Mazda seals and they'll be here on Monday. Good for me! But I hope Mazda is able to keep supplying the market for other old-school 13B builders.

 

You talked to Atkins—I’m curious as to why you didn’t consider or use his apex seals? Seems as though they would be well suited to your application.

 

Here's my experience with Atkin's seals. It is limited and very skewed.

I bought this engine as a zero-mile rebuild about a year and a half ago (off epay... my biggest mistake). I spent that time rebuilding my suspension / steering / brakes, and had my OE tranny rebuilt with miata gears. I was finally ready to install the engine and started turning it over by hand.

Suck-swoosh-suck-swoosh-suck-quiet. Something wrong with one of the apex seals. Looking in the exhaust ports I found this...

It's an apex seal bent/bowed/broke lower than the sharp edge of the rotor face. One of the apex seals on my "new" rebuilt engine was bad. So I shopped around to "local" rebuilders. The shop I chose tore the engine down and found that seal was cracked/broken. They said it was an Atkins seal and couldn't tell if it was broke due to install error or factory defect.

But that's my experience with Atkins seals. A brand new one was found defective with zero miles on it. Was it the factory or the rebuilder? Probably the junk rebuilder I bought from, since the apex springs were found to be used and too soft, and the main bearings were also used and worn below spec.. But that's my experience with Atkins Apex Seals. Limited and skewed, but it left a bad impression on me.

 

I have two engines I rebuilt using Atkins seals. both GSLSE. One has been running for a few months. the other has yet to be started. In the early stages I a pleased at this point. The future will see if my opinion remains the same

 

My GSL/SE based racing engine makes he kind of power you are hoping for with Atkins apex and solid corner seals. All of the springs are from Mazda. It is disconcerting when parts dry up but this isn't the end of the world like it will be when all of the non-Renesis housings are NLA.

 

so the thing that happened is that the rotary engine factory is a separate building, and while they have redone everything else, the rotary engine factory is as it was since it was tooled up for the Rx8.
or to put it another way, Mazda has a whole building that only does Rx8, FD, and FC engines (and GSL-SE rotor housings), so that is what they have been using it for.

which has been great for us, and for them too.

 

This is one of the reasons why I opted to engine swap my factory 12A with a fresh built 13B Renesis. There's no doubt that a 13B S4 or S5 swap would have required less fabrication .. however engine parts availability for a 30+ year old 2nd gen RX7 will most probably dry up before a 13B Renesis.

 

Well if thats the case I might as well buy some 12A springs and apex seals just in case.
Mazda is really stupid when it comes to supporting their vintage rotary engine. So many people who own rotary cars buy modern mazda ...

 

[QUOTE

*I want to go to the DGRR some day, but watching videos doesn't impress me much. Those roads look tame/lame compared to all the mountain and river roads we grow up racing in SE PA.[/QUOTE]

I can tell you, the videos do not do it justice! The roads, the scenery, the cars, but most of all(for me anyway) the people. It truly is an event that every true rotor head should put on there bucket list.

 

Oh yeah, I meant no disrespect. That's why I want to go - to meet everybody and share in it.