Speedometer Cable problems

[Will N]

I'm just getting around to installing the speedometer that I've been gather parts for since I got my T, as one of my winter projects. Its a Ford Standard Speedo. The repro cable that I bought doesn't seem to be functioning correctly. With the slightest amount of resistance applied to head end of the cable, it stops spinning within the housing for a little while, as if the winding of the cable were unwinding, if you get what I'm driving at. It's like the cable were wound in the wrong direction so that instead of tightening its twist when it rotates clockwise, it's loosening its winding. And then after a short while of not moving while it's torquing itself, it spins really fast as if the wound up cable is releasing the stored energy. It repeats this over and over again while the wheel is spinning. I've lubricated the cable generously with special graphite speedometer cable oil. Do you sage gentleman have any suggestions as to what might be the problem? Thanks....

 

[yachtsmanbill]

By resistance do you mean you can hold it back with your fingers? If so, thats not much! Can you take the speedo head off and verify its turning in the correct rotation? Is it acting like the clock is spinning backwards up against the pin?
Stupid point made here! I have a boat with twin engines, hence two mechanical drive tachs. They turn opposite rotation. Theres actually a left hand and right hand drive gear on the engine. I had them reversed and made a rats nest inside the housing! Did you have the drive apart and maybe changed a direction governing gear? ws

This is the drive gear. One side drives a signal generator for the electric tach upstairs and the other is a cable for the lower tach.

Note the DRIVING side is LH & RH and the DRIVEN sides are LH & RH as well. The signal gen is a DC generator and will spin either direction, BUT, turn the mechanical cable tach backwards and its trouble!

 

[Will N]

Yes, the resistance I'm talking about is if I hold my finger lightly against the end of the cable. The speedo needs to rotate clockwise to register. It spins freely with almost no resistance. And the cable rotates clockwise if you spin the front wheel in a forward direction. So it's not a matter of the drive and speedo being out of sync.

 

[yachtsmanbill]

Heres a really stoopid question as I dont have a lot of experience with the early speedos... Is this the unit that actually takes a chain drive in the housing? By chain I am refering to wire links that are hooked together... Just a thought... ws

 

[Will N]

The Ford Standard speedo uses a gear that mounts on the inside of the hub, with a cable drive. See the pictures attached.