Improved shifting for side shifters, bolt on? Maybe., Experimenting tonight. Options

[Dr Evil]

I have had this though for a long time to try and remove as much slop as I can in the shifting system. The tail shifter is a bit trickier, but not impossible. I have a side shifter in my new 914 and so, while I build up a transmission for it to drive to Hershey this weekend (this will be the raffle transmission, BTW. Trial by fire!), I decided to see how simple it would be to remove some of the slop.

First, see how much of a gap there is between the shift selector comb and the rod.

This is a huge amount so any bit that can be removed should be an improvement.

Step one was to add material to the sides of the comb faces (Yes, Scotty, I welded). Then, I hand filed the faces and re-formed them to a specific profile. The metal that was added was hardened and a real bitch to file. I figured it was worth it.

The end result was a much tighter fit.


There are a few parameters that I will not go into that need to be respected to get this to work, but the preliminary results were nice on the bench. With the material added and profiled on the faces, the stick throw fore and aft to select gears decreases significantly. There is still refinement that needs to be done on the profile, but so far the preliminary results are encouraging.

Next, I will build a jig so I can directly observe and adjust my profile. And I will also be able to see where I can add material to take up the slack that one feels when they are in gear and can wiggle the stick back and forth.

Once I get this prototype done and tested, I can do this treatment to any side shift console on an exchange basis and it will be a quick bolt on improvement (I hope).
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[GeorgeRud]

I always looked at that coupling and figured there was room for improvement in the design. Tightening the clearances should help, but I assume there must be some 'wiggle room' to allow the slight angulation as you shift through the gears.

Would a system composed of rod ends allow for the necessary movement and cut down on slop, or is there more clearance inside the gearbox that would negate any improvements to the external components?