The Albins ST6-M automatically locks the reverse gear out. To put it into reverse the driver must pull a cable to disengage the lock and only then downshift. This makes a lot of sense because it’s a sequential transaxle and you don’t want the driver to accidently put the car into reverse when slamming through downshifts — seems like something that I would do.
Cable bracket in foreground, lock shaft without the cap to the right
Since I’m using paddle shifters and a pneumatic shift servo I don’t want to clutter the cockpit with another lever/handle and I really don’t want to run a mechanical cable to the rear of the car. Instead, I will program the MoTeC ECU to monitor the gear position sensor and to ignore downshift commands if the car is in neutral (i.e., reverse is next) and moving. I’ll probably also require the driver to depress a button on the steering wheel to enable reverse as an additional safety measure. So rather than a mechanical lockout, I’ll have a logical one.
From left to right; Cable bracket, lock shaft cap and lock mechanism
A spring keeps the lock engaged and to disengage the wire pulls the lock’s shaft outwards. The wire is attached to a cap which utilizes a set screw to engage a groove in the end of the lock’s shaft. To keep the lock disengaged I machined a spacer on the lathe to replace the cap. It uses two set screws to engage the groove in the lock’s shaft and keep it pulled away from the transaxle.
Custom spacer (fore) and lock mechanism (rear)
I was thrilled, I machined exactly what I wanted the first time which doesn’t happen all that often. The last step was to install it by pulling the shaft out, holding it in place with non-marring needle nose pliers while sliding the spacer over the shaft and tightening the first set screw. The challenge was that there was very little room between the spacer and the transaxle to grip the shaft. This resulted in lots of profanity and no success.
Frustrated with that approach I wondered if I could remove the lock mechanism, compress the spring on the bench and install the spacer. How much damage could removing two socket head cap screws cause? In this case none. I pulled the mechanism out, compress the spring and installed the spacer. I then began wondering if I could just replace everything with a cover plate so I called Weddle… “yep, no problem removing it so long as you have an electronic lock out.”
Do’h! I made a beautiful part to solve the wrong problem, so into the recycle pile it went. I designed a cover plate, 3D-printed a prototype and laser cut a final part from 1/8” 304 stainless steel. Problem solved!
3D-printed prototype (left) and final stainless steel part (right), the hole in the middle of the prototype was to reduce material and print time