Shift coupler orientation, vs Options

[smdubovsky]

I replaced a bunch of shift bushings and adjusted the shifter the other night. But, I was suprised to see how the side shift works. (You must excuse me, I've only worked on taildraggers to this point) It twists the shaft by moving it side to side. I understand that the factory orientation of the shift coupler has the set screw pointing down. (This is a pic I stole from Mueller - ignore the extension for the V8)



This allows the motor/chassis to flex up/down but puts the shaft in a mild bind when in 1/R or 4/5 planes. Does anyone else notice this? It looks to me like the application is screaming for a helicopter/apex coupler:



Anyone ever done it? Since my car has the side shift conversion, I could just fab a straight rod, weld the coupler to it, and weld a boss to the other side of the coupler to tap for the cone screw - like Mueller did for the V8 adapter. On the tranny end, I could turn a rod to the right OD, and drill a hole to receive the set screw that goes back there.

Look to me like it would take up the misalignment in both planes and make the shifting more precise. Also looks easy to do. Anyone BTDT? I've installed a rennshift, but the side-to-side vaugeness could still be improved...

Tnx!
SMD

[smdubovsky]

Mueller,
Tnx. I'm familiar w/ the wevo bits, but didn't know they had an application that fits the 914. I just checked their website, looks like I'd have to buy a bunch of their bits and weld them together anyway. How did you drill a tapered hole - or did you? I thought of drilling a straight hole, slightly larger than the OD @ the nose of the set screw, so that I catch the wall of the taper part way up. That or I make a tapered single flute drill out of tool steel.

Geoff,
Its a factory 6. I put the 911 sport mounts on the tranny, but dont know if a stiffer firewall mount is avail. I haven't really dug in there to see if I can machine some bushings for it either. Im not really interested in going to solid mounts.

Brant,
When they did my side shift conversion, they didn't "phase" the coupler correctly when it was rewelded, so its kinda like 60deg off. Brad caught it on the PPI, but it was making me wonder if a full 90deg would be better. Up/down chassis flex might still bind it a little on the front to back action, but it would be constant in every gear.

Tnx,
SMD

[brant]

Brant,
When they did my side shift conversion, they didn't "phase" the coupler correctly when it was rewelded, so its kinda like 60deg off. Brad caught it on the PPI, but it was making me wonder if a full 90deg would be better. Up/down chassis flex might still bind it a little on the front to back action, but it would be constant in every gear.

Tnx,
SMD

I know a half dozen 914 race cars doing it.
but they are all caged and probably have less chance to flex

I know with my AJRS shifter, linkage mods, and custom delrin/brass bushings throughout... I am amazed at how precise my shifting is now.
brant