HI, this may be a stupid question but i can't really find the info anywhere. Are all 12a engines the same, do they vary a little by year? I want to find a second engine at the junkyard to rebuild before pulling the current running engine from my 83. Also don't maybe places have laws that you cannot engine swap down a year or whatever? or wil they never know

Thanks, and if the question is really stupid, just laugh or something

 

just kidding , the housings are all the same as well as setup but the differences come in with the carb , emissions , rotor weight , counter balance , flywheel , etc.


if you go to the stickey at the top of the page "performance vendors" there are plenty of site listed that can go into greater detail

peace

 

thanks, is it better to have a ligher or heavier rotor if i want a bridge port engine that i don't want to rev over 8500-9000 using steel? apex seals... or maybe carbon, not too sure the differences in performance

nick

 

On rotors, always go lighter...if revs won't pass 8500 RPM, then steel is preferred for durability and you can also nnnaaawwwwssssss it with a 100 shot....

 

thanks, so i guess 83-85 12a would be better becuase it is 9.6 lbs a rotor. Any ideas for apex seal thinkness if i use a steel on a bridgeport? and is a thicker apex seal hard to install when rebuilding?

 

you already have the thicker 3mm seals in the 12a. going from 2mm to 3mm requires machining of the rotor to accept them.

 

Here is a little run on what I've come to learn about the seals from the people on this forum.

Apex seals:
Steel - 8.500 RPM and lower.

Carbon - 8.000 RPM and higher, but don't last that long. (somewhere around 20k miles). Designed for racing only. They do NOT seal well at low rpm's. Not recommended for turbo, supercharged, or nitrous engines. Recommended for bridgeport. (but not if you are planning on doing everyday city driving.)

Ceramic - $1000+ per rotar. If you have the money go right ahead.

 

thank you very much for all your help!!, got another question for ya ...if you rebuild an engine you need new apex seals and new gaskets right? and good housings and rotors...

thanks,
nick

 

There are also corner seals, side seals, and oil control o-rings to check.

 

I must reccomend the Atkins rebuild video to all who are rebuilding a rotary.

 

Have yall every seen a 6port 12a? A guy here in Dallas has one! The motor came from Japan (obveously) and was transplanted. The guy autocrosses the car, it makes nice power! The car is for sale too.

 

That's not entirely true. Mazda used many different housings over the years all with different sized ports and runners. The Series 2 and 3 Rx-7 plates are the best to use as they have the largest ports in standard form. (excluding later models)

 

revhed, if i used a 83-85 12a in my 83 it should work out fine, plus be the best choice for me to rebuild?

yayarx7, isn't that only for a 13b or is it all the same basically

 

1 dollar, I would look for an 84 or 85 engine becuase they will have the lighter rotors.