I'm buying a rebuilt 13B out of an '85SE to drop into my '84SE. The engine is street ported and the seller said that the "rotors are pinned." I did some searching and can't find a definition of what this means. Yeah, I'm still learning about this whole rotary thing! Any clearification would be greatly appreciated! Thanks.

Also, any major differences that I need to know about between the 84 and 85 configuration?

 

Pinning the rotors prevents the bearing from spinning in the rotor. This mod is done done for high performance, high rpm engines. I believe Mazdatrix and Racing Beat offer that option.

As far as differences between the 84/85 engines, there aren't any of importance to mention.

 

I thought pinning refers to circlipping of the rotors. It's done to stop the rotor gear from "walking" out of the rotor at high revs.

 

I've seen pics of pinned rotors for the reasons I stated earlier. I vaguely remember the circlip mod and it will prevent walking, but not spinning. Both appear to be valid mods, not sure if they are done concurrently but that would make sense if they were. A quick check of either MT or RB should answer the question. Fwiw, you are one of the few members on the forum who's knowledge I'll dispute.

 

i thought pinning a rotor means putting a set screw into the rotor bearing so it won't spin or walk. which means the bearing will roll up onto the set screw and seize onto the e-shaft. then more engine damage occurs before the rear tires lock up and you spin out of control. better to just red loctite the rotor bearing in place.

using a snap ring to hold the rotor gear into place sounds like a good idea too, but the snap rings have been known to explode.