Hi all, I found a 12a from a 1979 RX7 and I might be getting a 1985 rolling chassis that originally had a 12a engine.
Any idea if this engine from '79 will work with this chassis? Any foreseeable issues?

 

How complete is the chassis?

79-80 transmission doesn't fit the 81-85 bodies, the shifter is moved back in them.

 

The chassis is complete, just missing engine, transmission and driveshaft.
Good to know about the 79 transmission not fitting 81-85 bodies.
There is no transmission with this motor though. Would an 81-85 transmission work with this motor so it could fit the chassis properly?

 

The carbs have their own differences along with the carb wiring harness. The alternator on the 1979/1980 have an external regulator while the 1985 alternator is internally regulated. The 1979 exhaust manifold is different. The clutch hydraulic thread sizes are also different. It's best of you can get all the external parts from the 1985 and then just use the bear keg from the 1979. The 1979 uses 215mm clutch disc while the 1985 uses a 225mm. You need to use the flywheel from the 1979 engine. This is because the engine is balanced to the flywheel year. There is some cross usage, but not for the 1979 to 1984.

 

Great info I wasn't aware of, thank you for that.
I guess the best would be to source a 1985 12A engine then?
Or would some earlier ones work as well? I'd want the least amount of headaches possible

 

Everything KC said with one small correction, only the 79 had the external regulator. Also the 79 has a points dizzy, ,so you really want to get the dizzy from the FB (81-85) motors and then put together a strong ignition system. For a 30% lighter flywheel you can use one from an 82 with a 12A just fine. It is close enough to not cause a balance issue and is 23 lbs versus the 79 flywheel thats 32 lbs.

 

Good to know, thanks. I don't have the 79 engine yet and wondering if it would be a much easier install if I sourced an engine up to '85? I would assume an '85 would just be plug and play.