ZF Shift Pattern

Ian Clark

Supporter
Like it says on TV, trained professionals, please to not attempt this at home! No easy task routing the gear selector down the sill in the CAV. The shift rod travels along the cavity originally provided for heater plumbing which has bee re-routed to the console. Notice the normal H-Pattern is for 2nd>5th gears. 1st is halfway across the neutral gate to reverse and back. On the track, 1st would mostly be used for start and leaving the pits.
 

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Ross Nicol

GT40s Supporter
Ian
Can I get some more photos and details of your shifter setup.I'm changing mine at the moment and I think your setup could be just what I need. It certainly gives short throw.
Ross
 
Ian, I am doing a similar excecise at the moment with a CAV, and I am concerned over the reduced lateral strength in the area of the gearlever where the chassis box section is cut. I am adding a triangulation web horizontally to pick up the full width of the box section at right angles to the cut box, with webs, to replace the strength lost by the cut. Frank
 

Ian Clark

Supporter
Hi Frank,

I'll post pics of our shifter openning fully panelled and tig welded. Does look a bit gaping in these pics. Once it's boxed in the tub will be locally stronger in this region.
 

Ross Nicol

GT40s Supporter
Hi Ian and Frank
My questions for you Ian
1/ Is there a ball joint at the bottom of your gearstick?
2/ Is the gearshift heavy.
I've measured the ZF forward and aft distance from neutral to 2nd or neutral to third 20mm or 3/4".This movement translates 1:1 at the gearstick and my current shift is very heavy, because the ratio I have,gives me a short throw but heavy .I've made a mock up of the up link in your photo and it cuts down forward and aft stick movement quite a bit as shown in photos.I presume the rod end rides up and down the stick as you cross the gate, which should allow a ball joint at the bottom.Let me know if my assumptions are correct.I've just shipped in 2 mil spec APEX gearshift /steering uni joints for the shift, very nice but expensive.
Regards Ross
 
Ross, the art is in the offsett distance between the c/l of the rod and the c/l of the rod joint on the lever, and of course the similar offsets at the other end. I think my measurement is a little larger than Ians, but then I do not use the ZF selector shaft box either. Frank
 

Ross Nicol

GT40s Supporter
Frank, thanks for confirming my observations.I, like you don't have the ZF selector shaft box.However I have the genuine ball on the cross shaft, and have fabricated the rest.I've spent quite some time comparing a stock selector shaft box( on loan from a friend )to mine. The fore and aft movement is the same but because the drop shaft is longer this translates to more lateral movement at the stick.I'm going to make a box exactly to the original, which only leaves the stick ratio to sort out.Do you have the same setup as Ian? I want a short throw shift with some mechanical advantage. My shaft alongside the seat is about where Ian's is so a stick with similar height will be ok.Is yor setup the same Frank with uplink to rodend? If so can you give me details of it please.
Regards Ross
 

Ian Clark

Supporter
Hi Ross, There are many ways to skin a cat, but that's a different story... Anyways the shifter shown retains some of the OEM Audi parts used in the CAV factory shifter. It's a perfectly fine part that gives smooth motion, allows for reverse lockout depression if a shift gate plate is used and prevents the shaft spinning (plus it came with the car!).

The throw on this shifter is more like 2" either side of nuetral with a reasonably narrow gate. The shift effort certainly more than an Accords but not crazy either. Imagine about one third the effort you have now.

We have built and scrapped several gear selectors to upgrade the CAV original units and now have systems that will work equally well in any GT40 reproduction that is ZF equipped.

The next generation Right Hand Shift is self contained and not dependant on mounting to a particular side wall structure as shown in this example.

There is no end of entertainment in these cars if you get your jollys from homegrown problem solving, ah the challenge of building your own car!

Good luck with it and please contact me directly if I can help, I've been a bit busy lately and have to admit not checking all posting.

Cheers
 
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