Rotary Engine build Blog

Building the Rotary Engine is all in the right tools, experience and knowhow. Get it right

12A, vintage racing 12A

5 Min Read

Rotary Engine Build tips | Using newer Stationary Gears

12A vintage racing rotary engineWith the rotary engine, there are a few things that can make or break a rebuild. 


Using new seals and springs is a must.

Checking every set of parts with a digital vernier caliper (down to .0001) ensures a quality build.


What most people do is to use or reuse the stationary gears. This is fine if you have a motor that hasn’t had a lot of racing miles on it. What if you are going racing?


For every high performance build, I highly recommend using new style stationary gears. In the case of this 12A rebuild I am currently on, because it is for a vintage racing Rx7, we use the FD stationary gears.


These gears are cut down to fit the 12A engine with oil porting and race bearings. 


Why go to all this trouble? 


Stationary gears from the early years were soft. Add in years of hard driving and they are even softer. The FD turbo engines came with hardened stationary gears and they fit nicely in the 12A housings once they are machined down, oil ported and fitted with racing bearings. 


racing rotary enginesRemember, these stationary gears do very important work, keeping the rotors where they should be as they spin.


When rebuilding 13B motors from 86-91, we would then use new Rx8 stationary gears if the motor is for competition use. That has some specific tactics to make them work, but you get the idea. 


The bottom line is that building in safety and reliability comes from using the right parts in the right places.


When I put the final torque specs on these motors I don’t want to have to see the internals any time soon other than a tune and maintenance. Details matter, do it right.


Ask questions, knowledge & experience matter to make good decisions

Topics:   12A, vintage racing 12A

google-site-verification: google66f53be324ef579e.html