seeking knowledge: 12A mated to FD 5-speed trans
 

Hello fellow Wankelists!

I'm getting my old '79 back on the road, and am in the middle of an engine change as the original engine smokes terribly (despite starting and running very nicely).

I have an FD transmission and an aluminum flywheel squirreled away in hopes of a future 20B swap.

It suddenly occurred to me that perhaps I can bolt the FD 5-speed on and ditch the old 4-on-the-floor. Yes, I'd probably need to modify the drive shaft, and fab up a trans cross member or an adapter of some sort, and perhaps a few other things.

Question is, can anyone foresee any trouble, or have any experience mating FD trans and a 12A together in an SA chassis?

thanks!

It would a lot easier to use a TII transmission. FDS have a pull type clutch and im not sure about shifter location. Its very easy to mod a TII trans for stock shifter location. Then you just buy a yoke from mazdatrix and have a shaft made.

Thanks for the response!
By "pull type clutch", do you mean the direction the clutch slave cylinder acts in?

The FD trans appears to have two positions in which the shifter may be mounted. The forward position is capped off with a plate, and happens to line up nicely (measurement-wise) with the SA's shifter hole in the body.

I'm considering this because I have the FD trans already, and presumably it is the strongest of the bunch. I'll need to do the work now or later-- might as well save the expense of buying a TII trans. hehe

I say yes, it will fit, you will need to change over to a 12A automatic CW and use a steel flywheel of choice. Then just use the stock FD clutch, pressure plate and starter.

It will fit yes. The FD trans is not the strongest at all. The high power FD guys swap to TII transmissions because theyre the strongest. I believe you can convert them to push type clutch but I think thats done using TII trans parts like bell housing, etc. It should work with an FD stock clutch setup not 100% though ive never owned an FD.

thanks again for the responses.
I have a new aluminum flywheel for the FD trans. Will it not work with the 12A's original counterweight?

All Rx7 flywheels are a one piece design with the counterweight built into it. You need to get the separate counterweight that would have been used on an automatic transmission. Check with Mazdatrix or Racing Beat to see if they still sell this. I know the 12a parts are getting hard to find. If they don't have the part then post a wanted thread on here, someone will have one.

Once you install the auto counterweight then yes you can use your FD aftermarket flywheel and clutch etc. I don't know what's involved in making your clutch pedal activate the FD's clutch though since I've never tried (I went the T2 route) Hopefully someone will chime in.

I'm moving this to the tech section, this isn't a build thread :)

This is great info, thank you all again!
It all makes sense now. Nobody said anything to me about a counterweight, as I'd mentioned when ordering the aluminum flywheel that it was intended for a 20B conversion. No doubt a 20B already has the separate auto counterweight.
Does anyone have input on which gear ratios would likely be better for a n/a 12A? FD or TII?