Just finished porting my rx7 12A and want to build it now. But, found that my rotors are worn in the apex groove. Are there any diffs between capella rotors and RX7 ones apart from the obvious combustion chamber shape?

I have a perfect set of capella rotors.

Would they make different horsepower and are they heavier etc.?

 

... what's a capella?

Jon

 

http://home.alphalink.com.au/~hillsk/capella1.htm

 

LOL! A Mazda Capella is almost the same as the RX2 but a bit newer with steel 3mm apex seals and single point distributer among other things.

 

That link says the capella models are piston cars. I don't think the pistons will work in it. What exactly are your rotors from? An RX-2 12a?

 

well, I suppose they named the models different in the USA. These rotors look the same as the RX2 but dont have 6mm carbon apex seals.

Is there anybody that has any idea what I`m talking about?!?!

 

Yeah, I know what you're saying. In 74, Mazda went to the 12B as the internal designation for the engine. They had a lot of street 'cred with 12A so they kept the name and castings, but it was always referred to as the 12B, at least at the time.

The S3 car you have was the same as the 74 I have, and Capella was the right name to use in Japan and maybe South Africa. In the home market, it was actually the Capella RX-2. In the states and Australia, the Capella was a piston car with a lower trunk floor and different taillight and sheetmetal, along with the boinger engine.

For the 73-older 12A, they used an older thermal reactor design, twin dizzy, top-mount starter, 6mm apex seals, and some other wacky things. The 12B from 74-on survived largely unchanged through 79-80 when they went to electronic ignition. That engine, like your "12A" from an SA or FB, used 3mm apex seals, single dizzy, bottom-mount, etc which is why they look nearly identical. I don't remember seeing any differences other than the shape of the bathtub, but maybe Jeff20B would have some ideas. I think you'd be good to go.

 

Thanx Crit! I dont know anything about 12B coz these housings all have 12A on them. But I wont disagree with you on that.

The distinct dif between the 6mm and the 3mm motors are the Mazda Logo on the rotor housing. the 6mm ones only had 12A (some had TCP closer to the intake port) on them where as the later(12B) ones had 70`s style Mazda bandge ( still with 12A) casted on them, the way as the early 13B`s had.

Also, the early end plates had 3B on and the newer ones R5.

 

Yeah, you'll never see 12B on any housings. It was just an internal designation at Mazda when they made a substantial rev to the design. The public loved the 12A, though, so the name stuck. Nobody other than the engineers ever saw a 12B designation, but it was still useful at the time when it came to keeping the parts straight. It's now more trivia than anything.

 

Might get better feedback in the old school section

 

someone isnt a very good reader..... the capella re isnt a piston

 

I've moved the second thread you made over to the Other Rotary section so it gets some views.

Jon

 

Thanx Jon

 

I saw that-the "RX-2"'s had "capella re" with the "RE" in red on the glove box lid, but for the most part the "capella" name is used for the piston models. Unless you live overseas...