I'm building a 12a PP for my Rx2 and plan on using the 12a core i have, which is from an 84 1st gen. But i would like to have some sort of old school in the motor. i have a real clean set of early 6mm rotors and seals I want to use. Well, I have the complete motor and rotating assembly really. But I only really want to use the rotors.

Was there any reason Mazda swapped to the 3mm seals in the 12a besides cost? Same thing for the dual side seals? Would I even need to use both side seals?

The stock 6mm seals are carbon with aluminum centers I believe. And are solid 1 piece seals. These would work great for my PP motor, in theory anyways...

 

Narrower seals seal better, and allowed mazda to use a harder and heavier material for the seals without compromising high rpm sealing.

Your 6mm seals should be made of an aluminum/carbon alloy. Its a really neat material in that carbon molecules are basically held in a suspension of aluminum.

The double side seals are likely a workaround to accomodate inaccurate machining or material limitations of the time that made sealing problematic. You probably would need to run both to get acceptable compression.

 

The main benefit (and the main reason) I would like to use the 6mm seals is they were originally designed for PP motors on the 10a. And the fact that they do not wear the housings nearly as bad as the newer 12a/13b seals. And with 12a housings getting harder and harder to come by, this might be a great trade off.

I am unsure on how to sepc the apex seals. Any old school guys know how to check these?