I read on rotaryaviation website that they dont make apex seals for 12a's. Couldnt there 2 or 3mm seals be used somehow? I read about guys interchanging rotors-13b rotors in 12a housing or vise-versa. Can they be worked to fit a 12a?

 

from what i "hear" the RA seals are good, but their springs suck

 

Yea but whats makes then not fit 12a's?

 

It is not the width of the seal that is the problem (2mm or 3mm), but the length of the seal. The 13B engines have rotors that are 10mm wider than the 12A, so the seals would be too long. The interchange thing that you you heard about is using 13B rotors, housings, and e-shaft with the 12A side plates. This creates a 4 port 13B engine (this only works with early (pre '85) 13B housings because because of the location of the coolant seals).

Kent

 

just order some Atkins 12A seals.

 

Much cheaper from Rotary Aviation.

 

there seems to be some quesitons about there longevity, some guys are talking like 10K miles and there having problems. while they might be cheaper, do you really want to save a few bucks and then have to tear your engine apart 10~20K miles later cause they don't last as well as the OEM parts?

I would personally do some more research first about the longevity issues and there were some fitment issues as well I think (warpage or something).

Kenn

 

From what I've been able to gather, this has only been a problem on higher-boost engines, and the seals in question came from an early batch from a supplier with questionable manufacturing techniques.

Rotary aviation has had no problems with these seals in N/A and aircraft applications, and has (I believe, correct me if I'm wrong) switched to a different manufacturer. In spite of this, the jury is still out on these seals because as far as I know we have yet to see a set of them accumulate high mileage in a high-boost application. They simply haven't been out long enough for anybody to rack up the mileage.

 

The reason I said Atkins is because RA doesn't make 12A apexes but Atkins does and their much less than Mazda seals.

 

Good to know we have options other than Mazda for these. I haven't heard anything bad about Atkins either.

 

Atkins it is then!