Background: rebuilding a motor for the REPU. New 84-85 GSL-SE rotor housings, new S5 rotors, new 3 piece apex seals. 4 port Streetport, 3b end plates, 12a intermediate plate, weekend driver + some autocrosses.



I measured two new 3-piece apex seals and they were 80.10mm long. My rotor housings narrowest points are 80.0020mm and 80.0049mm. The How to Modify your RX7 book says to sand the apex seals down to 79.90mm length for street use. Some people don't clearance the length of new Mazda seals and say they're fine as new. Other people say to clearance it 0.0015" narrower than rotor housing width. And others still say clearance it 0.004" to 0.0045" narrower than rotor housing width. Who is right?



The triangle piece is super glued to the upper piece. Should I super glue the lower piece to the rest of the apex seal, to make it all into a one piece? So I can sand it all as one piece and get a uniform cut on the apex seal? How thick is the super glue between the top piece and the triangle piece, should I subtract that out when computing the length?



Also, I assume I don't sand the triangle piece. Just sand the other end(s).

Well I exchanged them for stock 2-piece Mazda apex seals. And the new ones are 80.09mm long. Now what? Do I sand them narrower or install as-is?



Does anyone here set the length of apex seals?

i understand that the triangles function is to set the length of the seal, or its self adjusting. but if you were going to measure it, then you'd measure the seal WITHOUT the corner.



once they switched to multi piece apex seals they don't list a length in the shop manual anymore

Sounds like I should just install them as-is and move on.

i agree!

As mike stated. corner apex seal tip is for self adjustment.. use the seal in it's oem stock form.