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).
(IMG:style_emoticons/default/happy11.gif)

[IanS]

So you say this can be similarly engineered for tail shift? Do you have access to a tail shifter to test/engineer?

[mskala]

So you say this can be similarly engineered for tail shift? Do you have access to a tail shifter to test/engineer?

For the -6 version of the tail shift, I did basically the same thing last year:
914-6 shifter slop improvement
It didn't hurt, but I didn't notice any real improvement either.

[Dr Evil]

So you say this can be similarly engineered for tail shift? Do you have access to a tail shifter to test/engineer?

For the -6 version of the tail shift, I did basically the same thing last year:
914-6 shifter slop improvement
It didn't hurt, but I didn't notice any real improvement either.

Mark, without addressing the internal shift mechanism you will see limited results. The problem with the tail shifter is majorly within the box. If you saw how these things actuate internally, you would be shocked. It is so loose as to be a joke. So much room for improvement. I would love to do a mod on a /6 if anyone is interested. I would throw it in with a rebuild. The stuff that needs to be done to a tail shifter would best be done with the whole box here. If I have the box to play with, I can adjust to the box and its rods. Otherwise, I have to leave a little slop so it will fit all boxes.