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-   -   Need help with motor identification (https://www.nopistons.com/vintage-mazda-rotary-70/need-help-motor-identification-73037/)

dirty 12a 08-24-2009 12:17 AM

I picked up a free 12A free from a buddy and I would like to put it in my Baja Bug. I originally posted in the 1st gen RX-7 forum, but after more research I found out the motor is older than I thought. The housings say 12A, but the two distributors kinda threw me off. I've looked all over the net to decipher the engine serial number, but no luck. I'd like to at least find the year of production so I can find a wiring diagram, torque values, ect. Does anyone know were to find out or can identify the motor based on serial numbers? Thanks!



Dirty 12A

edsrx3 08-25-2009 09:08 AM


Originally Posted by dirty 12a (Post 833387)
I picked up a free 12A free from a buddy and I would like to put it in my Baja Bug. I originally posted in the 1st gen RX-7 forum, but after more research I found out the motor is older than I thought. The housings say 12A, but the two distributors kinda threw me off. I've looked all over the net to decipher the engine serial number, but no luck. I'd like to at least find the year of production so I can find a wiring diagram, torque values, ect. Does anyone know were to find out or can identify the motor based on serial numbers? Thanks!



Dirty 12A



With 2 distributors its a 12a twin dizzy. 72-73 vintage from an RX2 or RX3. Originally with 6 mm apex seals. There are differences between that block and all the other 12a's. You would need a specific bellhousing to bolt up to it. The water pumps are getting hard to find. The motor was problematic and newer versions had more durable housings and plates. Unusual to find a health running twin dizzy and expensive/hard to find parts to rebuild.



I'd make sure it's realy a good runner before you went to far with that motor.

dirty 12a 08-26-2009 10:10 PM


Originally Posted by edsrx3 (Post 833412)
With 2 distributors its a 12a twin dizzy. 72-73 vintage from an RX2 or RX3. Originally with 6 mm apex seals. There are differences between that block and all the other 12a's. You would need a specific bellhousing to bolt up to it. The water pumps are getting hard to find. The motor was problematic and newer versions had more durable housings and plates. Unusual to find a health running twin dizzy and expensive/hard to find parts to rebuild.



I'd make sure it's realy a good runner before you went to far with that motor.







Thanks for the info, that's exactly what I needed to know. I was told that it was a running motor before it sat, but it looks like that was a long time ago. I'll pull it apart this weekend and see how bad it is. Thanks again.

j9fd3s 08-28-2009 10:48 AM

housings will look new, apex seals in the 6mm variety are HARD to find. other than that, its a little different, but pretty standard 12a.



there were some variations in these engines, the only real big one is the 73 rx3 has a bottom mount starter like the later motors. everything else is a top mount starter.



if you need parts ive got plenty, like 3-4 motors worth

Mazdat 12-06-2009 09:30 PM


Originally Posted by j9fd3s (Post 833474)
housings will look new, apex seals in the 6mm variety are HARD to find. other than that, its a little different, but pretty standard 12a.



there were some variations in these engines, the only real big one is the 73 rx3 has a bottom mount starter like the later motors. everything else is a top mount starter.



if you need parts ive got plenty, like 3-4 motors worth



i have a twin dizzy 12a in my 73 rx2, its original to the car, thinking of swapping it later, runs real good though


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