Embarrasing but...
I tried to install a 12A from a 84-85 RX7 into my RX2 yesterday. It seemed the tabs on the front of the RX2 manual transmission would not match-up with the tabs on the rear housing of the 84-85 12A.

What's the secret? How do I bolt an 84-85 12A onto an RX2 transmission?

 

Hmmm, are you certain that you have a 12a? 84-84 RX7's where all GSL-SE's that only came with the larger 13b. The stock Rx2 manual trans won't fit, since it's a 12a setup.

 

The newer engine is defintely a 12A, as was the orignal motor that was in the RX2. Stamped right on the rotor housings.

 

umm... no.

all GSLSEs were GSLSEs that had 13bs. But they had the GSL, GS and base models as well with 12a through 1985

 

is it a sidemount starter?if so,it should mate.

 

The RX2 transmission has a top mount starter. I converted the RX7 12A from beehive to front-mount oil cooler, and this opened-up the space for the starter. It looks like the starter will not be a problem.

The upper tabs for the "transmission to block bolts" look like a problem.

 

can you get pictures?

 

74-85 12As won't bolt up to original Rx-2 4 speed box! Twin dizzy 12As had totally different bolt hole configuration. You'll need a rotary gearbox from 74 onwards. If you really want a 4 speed you could use an rx-4 or repu or some base sa22s had them too.

 

Ozzy, thanks you are correct. As per Mazdatrix, the 1974+ years all have the same bolt hole pattern. I have a 1972, so the engine's rear housing has a different bolt pattern. I need a 74+ transmission, or, at least a 74+ bellhousing for an RX2, to mate to the later motor.

The easiest dimension to check is the upper right and lower right transmission bolt holes (facing the rear of the motor.) If they are 9.5" apart, it is early (pre-1974.) If they are 10.5" it is 1974+

Does anyone have a 1974+ RX2,3,4 transmission they want to sell?

 

74-80 are going to be your best options as far as shifter location and requiring less hacking of you trans tunnel, as all 5 speeds are longer than the stock 4 speed is. I have 79-80 rx7 5 speeds in both of my Rx-2s and a Rx-3 SP 5 speed in my 73 Rx-3. You're going to have to get your driveshaft shortened and balanced too. Please don't listen to any of the clowns on here that insist on you throwing away your 2 piece drive shaft. It's there for a reason so use it! Hit up your junk yards for a box and make sure to grab the bell housing bolts and the starter too.

Good luck grasshopper

 

hmmm so that 72 4 speed i have laying around is rather useless.

 

I have a twin-dizzy motor that will mate right-up to it. PM if interested

 

RX-2 13-B TII streetported with semi-pport T72 turbo ONE PIECE DRIVESHAFT never had a problem 130 mph grasshopper

 

I believe late 73 model had a side starter that mated to a early engine, I had one years ago. I never seen one since.

If you have a later 12a, I would install a 79-80 5 speed and yes you can install it with the original 2 piece drive-shaft, No need to shorten it or re-balance it, just some minor mods that will take about a hour.

FYI: RX2-Mazda-Fan and Gravity Fed, 74-91 engines will bolt on to any 74-91 transmissions 12a or 13b as long as the flywheel clears the bell housing.

 

Thank you very much Ozzy, Siranako, and Rotorholic.
I know the ways of the FB, but the mysteries of the RX2 I am still learning...

 

Rx7 trans and shorten the shifter. Custom drive shaft

 

Two FC 5 speeds on L.A craigslist and also found this place parting a wrecked 82 rx-7.

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