My engine is getting rebuilt, and I've decided to go 2mm because I don't really like the idea of milling the rotors, because they have to be perfect otherwise it defeats the benefits of them.
Anyways,

Im deciding between 2 piece, 3 piece or rotary aviaton seals. My motor will have a fairly large but streetable port and will probably make ~380whp. I will have every mod possible with stock twins (non-seq)

Mazda went from 3-piece seals to 2-piece seals, back to 3 piece. I heard this was because mazda found the 3-piece seals to be more durable, can anyone confirm this? Also, I do not know a lot about the rotary aviation seals, but they seem to be pretty good and people on this forum like them.

All input is greatly appreciated and any other seals could be considered also. I searched, but could not find anything comparing the different apex seals.

-scott

 

I'm basically in the same boat with you. Curious as to what the expert rebuilders say about this.

 

I've used all three, given my experiences, I would opt for the mazda 2 piece'ers, some people didn't like them, for me they worked good, and took some abuse, one of my rotors is dented, but the seals never broke...I think the aftermarket seal manafacturers need to get their machining standards and tolerances somewhat closer to Mazda's before they are truly a alternative to Mazda's seal..max

 

max... why would you chose the 2-piece over the 3-piece? I know you reccomend the 2-piece, but you never really said why you think the 3-piece is inferior to a 2-piece. thanks

 

I don't think the current Mazda OEM apex seal is 3-piece.
Mazda had changed over recently to the 2-piece, 2mm apex seal.

The Rotary Aviation apex seal kit I saw up close looked like it was hand finished.
Tolerance is not even close to what the Mazda OEM stuff is like.
We haven't run these seals yet, but we're taking a chance on them for a customer.

I've had the Mazda OEM 2-piece, 2mm apex seals up to 1150C - that's 2,000F!!! - on the EGT gauge.
We've never had warping problems with them yet, but others have reported that early batches have had warping problems.


-Ted

 

Rotary power in california told me to go with 3mm seals, as did Rotary performance here in Tx. thats what I went with.

 

Yes Mazda is back to the 3 piece seals, at least in Canada, I ordered the same part number , but got 3 piecers on the last order batch...
I like the 2piecers for reassembly puposes, they are easier to glue back together than the 3 piecers, I can do it by hand with the 2 piece, I used a piece of glass with the 3 piece'ers. I also like not having the lengthwise split for porting reasons, you can squeeze a bit more out of the port wall with the 2 piece, especially with a bridgeport. I would think by design they would take bit more heat, without the lengthwise split, they should not only have a higher heatsink ability, but a greater rate of heat transfer back to the rotor. I also found that on a worn rotor, the 2 piecers will yield less seal rock than a 3 piece, even though the tolerance measures the same..max

 

I'm going to 'cross off' the R.A. seals off the list. They just can't compare to the tolerences and long success of the mazda seals it seems...

cloud9.. I looked into 3mm seals..but they require perfect milling of the rotors.. it simply increases the margin of error for problems with the seal not being as good of a fit to the rotor

thanks, max, for that good comparison.. you know your stuff!

 

If your not planning on upping your boost over 1.4 I would just stay with stock seals. I haven't had any experience with the 2 piece seals but the 3 piece seals handle 1.4 with no problem. Also since your planning on using your stock turbines it would be a waste to go with anything but stock.

-Destin

 

bump

looking for more opinions... mostly now opinions of 2 piece vs. 3 piece seals

 

Whatever the case may be, stick with OEM Mazda seal, I've been using the 3 piece seal now for about 2 years, and drive my car at about 18psi of boost on pump gas, and it's my daily driver, and I haven't had any compression loss, or seal failures at all with the stock seal, it's been holding up to abuse very well.

 

when i was at racing beat for sevenstock 7, i asked one of the guys there about the benefits of two or three piece seals. He basically said the three piece seals better than the two piece seal, but it isn't quite as strong....to my best knowledge thats the only difference

 

I didn't know Mazda acturally went back to 3 piece?? So do RX8s replacement seals also 3 piece?? Can someone verify this for me?

 

I got a question on those who have actually installed them on your own...

I just had to install that set for a customer, but it looks like the RA apex seals did not like "super glue" at all.
I realize I wasn't using the "Super Glue" brand, but it was Devcon cyanoacrylic - not some cheapy brand.

4 out of the 6 easily broke off.
2 actually stayed intact.

Luckily, with the shape of the triangle assist piece, you can shove the piece into the groove after the rotor is installed within the rotor housing and not have it pop out.

So how did you do it?


-Ted

 

Are you cleaning the seals with isopropyl alcohol or brake cleaner before gluing them?

 

Yep, we got all of the "light machine oil" off the seals with brake cleaner.
I typically would get 1 out of 6 to break off doing this with the Mazda OEM apex seals, but these RA units were driving me crazy.

Welp, the motor is together, and it spins by hand so in the end it all works.


-Ted

 

I used no glue and just slide the springs into place. Works for me.

 

rx8 seal is too short for a 3 peice

 

Guys.....stick with the Mazda seals.
I've had both 2 piece and 3 piece up to 20 psi on pump gas....no warping issues.
I did notice teh 3 piece offer slightly better sealing @ idle....possibly the reason why Mazda may have gone back to 3 piece(if true).

JD

 

im def. not going with RA seals, espeically after what RETed said along with everyone else pretty much saying stick with mazda seals.

It doesnt sound like it matters too much whether one goes with 2-piece or 3-piece seals. Both sound like a good option even under lots of boost.

however, if anyone has an opinion over which is better, please contribute

 

At what HP mark would you suggest ditching the mazda seals in favour of ceramic items?

 

Never.