I was tearing apart my gf's 12A. One of the rotors is gone. When I pulled it out the rotor bearing was stuck on the e-shaft and inside the rotor where the bearing was its all grooved to hell. I need a new rotor. However I do have a 79 12a laying in the yard and I was wondering if a 79 rotor would work in my engine??? I checked the stats and on those years (79/83) the displacement and the compressions is the same which kinda makes me think that there would be no difference in the rotors. However I checked the mazdatrix site and they sell two different rotors for those year engines. Anyone have any knowledge on this???
thx for your help.

 

You need the 83-85 rotor, the earlier rotors have a differnt weight. Which one do you need, the front or rear? Sounds like you need and e-shaft and bearings too. You can use the e-shaft out of the earlier engine, not the rotors.

 

if you have a complete '79, the whole rotating assembly from that engine. just don't mix the rotors or you'll have balance issues.

 

i need the front rotor. i weighed the 79 and then the 83 they are both 9 lbs and my old eshaft is in good condition
both the rotors are identical as well.
is there any other way to tell any differences?

 

you need to keep a balanced assembly, the rotors have letters, a, b, c,d maybe e too. you need to figure that out so you keep them matched. pm me and i might have a good rotor for you.