Anyone know what the shaft diameter is on the FD alternator? I am getting an FD alternator to swap into my FC. I won't have a lot of time when I get my alternator so I am hoping to have the hole bored out on my double belt pulley before I get the alternator so it will be ready to go when I get the alternator.

 

17mm

 

Another FD alternator swap question: do you re-use the s4/s5 spacer where it mounts onto the water pump housing, or just put it in and tighten?

 

you use the stock spacer Howru..Put it at the back,between the Pump housing and the "rear Ear" of the alternator.

 

Got loads of info for wiring, but not about that spacer. Thanks!

 

Why not just get the SPECIAL pulley made specifically for this upgrade?

Link:
https://www.rx7club.com/2nd-generation-rx-7-1986-1992-parts-194/brand-new-dual-belt-pulley-fd3s-100amp-alternator-upgrade-860869/

 

I would if I didn't already have the Banzai non-underdrive dual pulley

 

What do you use for a spacer to run the FC pulleys?

 

You'll have to cut the spacer off the back of the FD pulley, as much of it as you can.

 

Bummer, I don't have the FD pulley. Got the alternator without it. Any other ideas?

 

go to an alternator Rebuilder.They will have the spacer.
Try your Local yellowpages.