Well its already installed and in a couple of weeks i should be able to post up compression numbers. I also took pictures which i shall update here soon.

They're black in colour and numbered (as per older RA seals) Anybody had the chance to speak to RA with regards to these "new seals"?

 

Are these the new Nitrided RA Seals people are talking about? If so how much did they run you? Please post pics of them if you have them.

 

yes, pics, please ...

 

also very interested! well in the compression numbers your gonna post... are you using new housings or used ones? judging from the way he posted this guys it looks like hes using the originals not the new Nitrided seals. yes please post pictures and anthing else you can share it helps everyone out but forget them just help me!

 

i emailed laura nd here's what she had to say:




Hi Dave- sorry for the delayed response - I am having email problems unfortunately.

We DO have a new seal - the RA Super Seal - which has been in use in a number of cars for the past 3 months or so. We still consider the product somewhat experimental until we get all the results from the current customers, but so far they are very successful. The seals are of the same base material as the current 2 mm seals BUT are nitrite coated. Although we have had very good reports from customers of our current 2 mm seals (including a number of drag racers world wide who use our seals in ery high boost cars) we believe the new "Super Seals" will be even more tolerant of excessive heat ( found in high boost and nitrous boosted cars and in the case of incorrectly tuned turbos). Again, we are not saying that the seals are "unbreakable" but we believe they will be extremely resilient even when abused.

 

you beat me to the info... thanks though! do you think you can get her to disclose who has the seals so we could possibly contact them?

 

doubtful.
you can ask if you want to though.

 

as promised.

 

Thx for the pic. So how much do these run? They also look just like these.


http://www.southcoastrotary.com.au/scrseals.htm

 

Looks like they finally went to small corner pieces to, thats a huge plus for me.

 

whats much better with smaller corner seals? and why is only one corner separte i thougth both were loose... teach me!

 

There's an older animated pic floating around here showing how an apex seal with a wider/larger corner seal seals against the housing. If that apex seal is machined to long then you will have a small gap underneath the apex seal where the corner piece meets the housing. This can potentially leak small amounts of compression from chamber to chamber. It isn't a bad thing. It can lower compression until the seals break in and the entire seal makes contact with the housing surface. Personally I like the older RA seals with the slightly wider corner pieces because they cause less housing damage. That small pointy edge from the stock corner piece really digs into the housing causing chrome flaking.

 

Nitriding is just an anti-wear coating.
It doesn't typically make the seal stronger.
I'm skeptical on any claims that makes the seal stronger.

I wonder if it's heat treated.
Heat treating make the base metal stronger and resistance against warping from heat cycling...which is what RA is trying to do...yet no mention of heat treating.

I'd still rather go with the triangle corner piece.
Have a wider assist piece allows valuable compression to leak through...i.e. blow-by.
Doing this under huge boost is asking for trouble.
Having this in daily driver just drops efficiency.
I'd rather have a pointy assist piece digging into the housing (which seals better) than take the hit on compression from the gap between rotor faces.
Unless you're using brand new rotor housing, this should not be an issue.
Are you guys building motors and expecting them to last 200,000 miles?


-Ted

 

T-von- Laura exchanged one set from the 5 or so rebuild kits we bought.

RETed- we'll never know until someone tries it.

So far, at least here in malaysia, we've used RA seals with good results. The reason for posting this is give a heads up to others pursuing a rebuild.

Also do check out my rebuild pics and comment.

https://www.rx7club.com/showthread.p...0&page=1&pp=15

 

Well I recently rebuilt my S5 engine with used housings and RA seals. The engine fired up the very first time without any ATF and has been running great so far (1,500 miles so far). I feel the small blow by is a small issue especially since the seals will still eventually break in(RA claims 5k for used housings). I feel the wider assist piece will keep the housing face more level with a better chance of better sealing over the long run. Once the edge flaking starts, compression tends to go to ****.

 

Sorry, I don't agree with your statements, especially the last sentence.
Unless we're talking about a really gouged rotor housing, I find compression numbers are 95%+ percentile.
I believe Rotary Resurrection has posted his experience on this subject, and it mimics what I have seen...and he has built a lot more engines than I have.


-Ted

 

Well truthfully there isn't really a proper way to compare the two. The RA seals are harder and should wear the housings faster. The only real way to test the differences between the small assit piece and the larger one, is if we had both types from Mazda. The pics below are of my 12A engine with 155k. I just feel this kind of flaking wouldn't be that much had the engine been fitted with a wider assit piece.

 

Wow, I wouldn't reuse that housing!


-Ted

 

Yea tell me about it. It sucks because both of these housing surfaces are in pretty good shape and would have been reusable had it not been for the edge flaking.

 

maybe, i think that kind of edge wear has more to do with housing design and coolant temps than apex seal design. 4 out of 5 12a's look like that, but how many 13b engines have you seen wear that badly?

in extreme cases the chrome just falls off the 12a housings, ive never seen that happen with an 86+ 13b.

 

Mazda experimented with larger corner pieces in the earl years, the negatives were to great so they switched to the current design.


I also still have issues with everyone saying RA seals are harder then stock when the stock are electron chill beam hardened on the tips, and almost as hard and ceramic like as you can get an iron alloy. RA's marketing says they are harder then their competiors, not harder then mazda.

Until I see actual hardness tests, I wont believe this.

 

If the flaking was due to the corner piece, how come it happens on both sides of the housing?

I pulled an engine apart once that had perfect housings, except the front housing has a slight groove all the way around on only one side. It was the side that had the "solid" secton of apex seal, and each seal from that rotor had a little "tooth" on the end where it had been running in the groove! If that doesn't blow the "corner piece causes flaking" theory out of the water, I don't know what does.

 

That's easy! Odviously were talking about the different housing surface applied between the 12a and newer 13b models. The main difference is the newer 13b's with the 3 piece seals on average didn't last as long as the 2 piece 12A and SE models. It's not that common to fine a 13b with over 150k on the original engine since the top piece gets so thin and so brittle it breaks. So it's too hard to make high mileage comparisons. Plus where talking about the wear differances between a 2mm 13b seal with a better housing coating and a 3mm 12a & SE seal with the older chrome surface. That's not really an apple to oranges comparison. So truthfully the only way to compare them would be on a equal playing field. Currently that equal playing field doesn't exist.

 

You know I wondered the same thing on my 12A. It could also be a number of possibilities. The older 12A/SE engines only had 1 spring to push at the corners of the apex seals. Guess what my 12a seals are slightly warped. This pressure being applied to the edges puts more pressure on the edges so they wear faster on the corners. This was completly the opposite from the last 2 13b's I took apart(87 and 91 NA). They only had small wear grooves on the side where the corner piece was and not both. I think it's a combination of the newer housing surface and the fact that the newer engines had 2 apex seal springs. Two springs equlizes the pressure against the seals and housing causing more even wear.

Below is a pic of my rear housing from my 91 vert with about 80k on it. Notice the groove on the back side but it was competly smooth on the other side.

 

did you even need to ask if we wanted pics :P