Apex Seals

[vex]

So I'm thinking I may pick up some new Apex seals to replace the old 3 piece seals I have but I'm a little concerned on which Apex seals to pick up for the right money.

My application is a turbo charged 6PI that will see within the first few months of rebuild (after break in) 5-8psi. Eventually I'll push the car to more pressure but only to achieve 300~hp and that will not be until I have enough to rebuild, or build a new engine from scratch to drop in off the bat.

As of right now I'm thinking of just picking up the regular Atkins seals but I'd like some opinions:

Would it be anymore beneficial if I pick up the cryogenically treated Atkins seals?

What about the one piece racing seals that Atkins sell?

What about the RA seals?

The RA super seals?

I'm not planning on running tons of boost pressure on a high compression ratio while in school, but I would like to have a reliable car that can handle tuning and still be okay to drive for quite some time. Any suggestions?

[Ender]

Here's what I've heard/read:
People have had good success with the regular Atkins seals, just make sure you clearance them (as you should ANYWAY, but some people think "Hey, they're new so I can just throw them in the motor and they'll work right." That's not always true, clearance your seals and you won't have to wonder if they're right or not. Plus, housings (especially used ones) differ in thickness, which is a big reason you have to clearance your seals.)

I've heard that the Rotary Aviation seals are harsh on the housings, that the housings take more of the wear than the seals, and you want it the other way around.

I would bet you wouldn't need the one piece seals, but they would probably work ok (however I don't know much about the one piece design versus two piece). They may not seal quite as well as the two piece design, but they might be slightly more durable. I honestly don't know for sure though, and just look at Kevin Lander's FC build to find out how important it is to use the newest, most expensive, flashiest sounding products.

Personally, I used new Mazda OEM apex seals with an Atkins kit for everything else. Unless I was going to build a really cheap/expendable motor or a crazy high power output motor (like 500+rwhp on a 13B) then I'll stick with Mazda OEM. They pretty much know their shit about rotaries.

Ceramic and carbon seals are available as well as different treatment options, but they're also usually pretty expensive. I think it's highly cautioned against to turbo a motor with carbon seals, too.

[Fidelity101]

Originally Posted by vex

I'm not planning on running tons of boost pressure on a high compression ratio while in school, but I would like to have a reliable car that can handle tuning and still be okay to drive for quite some time. Any suggestions?

Sounds like an oxy moron

[Ender]

The devil is in the details. Good tuning at reasonable outputs will help the motor last, bad tuning can kill a motor fast.

[classicauto]

Yes, you absolutely DO NOT want carbon seals. They are for N/A *only*

Personally, not a big fan of atkins apex seals. Had a strange failure with a set, which may or may not have been the seals themselves, and just lost trust right off the bat.

I've run OEM 2mm, 2piece for everything after that, and Iv'e had failures, but they didn't have ANYTHING to do with the seals themselves. The set in my car right now puts down 380whp. ALL OEM.

IIRC, mazda apex seals are about $30 each.

No experience with RA.

Know some guys running ALS, if you want a cheap set of "race" seals get them, they're pretty good. As for benefits over non-race seals, good question.

[Ender]

Originally Posted by classicauto

IIRC, mazda apex seals are about $30 each.

They're more like $70 each, at least from Mazdatrix. I got my set about a year ago for I think $300 from someone who didn't want them and that was a good deal back then, too.
http://mazdatrix.com/getprice.asp?partnum=11-C00C-N351

[Whizbang]

what im kinda curious about would be how a cryrogeniclly treated seal would behave. The process will make a material have higher overall "toughness" but the fracture point will be much lower. Essentially, in materials, a material will have a point where it will not deform permanently under a load. This is the elastic region. At a certain point called the "yield point". At this point the material will not completely return to its original state once the force is removed. This isnt really a bad thing. The material, especially steel, will become stronger through atomic dislocations. But what really will matter is how large an area of plastic deformation you have to work with. Things like glass have nearly no plastic region and fracture almost before the yield point.

what it means is that the treated material will break before the non treated material as opposed to deformating under a stress. So what i want to know is how exactly will detonation work on such a seal.

[85rx-7gsl-se]

I am running RA Classics and thats what my builder uses for all of his...So far so good

[NoDOHC]

I have heard that if you are driving it on the street, you need mazda seals. The 3 - piece seals make better sealing at low revs (like starting). Unfortunately, I just bought some seals and they don't sell the 3-piece seal anymore.

I am using Mazda seals (they ran the first 75,000 miles just fine, 200,000 in my NA).

[Fidelity101]

RAs are nice but they put more wear on the housings

[RETed]

Personally, I think almost every other aftermarket apex seal is CRAP.
I use and recommend Mazda OEM.
For super high boost / power applications, you can start to look at the ceramics, if you can stomach the $1,000+ price tag for a set.
Ceramics have no real advantage for street cars running under 20psi of boost and making under 500hp.

The older 3-piece design was more prone to damage.
The newer 2-piece seal is stronger (along the height of the apex seal).
The newer 2-piece seal should last longer due to it's design.
The sacrifice is sealing was very minimal; there is no reason to want the older 3-piece apex seals anymore.


-Ted