SPEEDOMETER TESTING

[CFD244]

Hi Folks

I want to test my rally speedometer with a drill. Can anyone tell me what direction the speedo cable rotates if you are looking straight at the back of the speedo.

Thanks

 

[Mike69cuda]

The speedo cable turns the way the needle moves, so looking at the back that would be counter clockwise.

 

[pishta]

yeah, lefty in direction of needle travel.

 

[CFD244]

Awesome! Thanks guys, I didn't want to damage it turning it the wrong way.

 

[Dana67Dart]

Don't think you can damage it by running it backwards. Backing up rotates the speedo backwards.

 

[CFD244]

Makes sense. But, I wasn't sure, and this is the place to get the right info. Thanks again everyone.

 

[sireland67]

Do a quick turn by hand, to see which way it moves.

 

[Mattax]

If you look at the input and turn by hand you'll see its a worrm gear. The worm drives the odo and can do so either direction.
It also spins the open shell. magnets turn the drum which is restrained (calibrated) with a tiny clockspring right behind the dial.

Even though its non electrical, I posted there 'cause most instrumentation discussions seem to end up there.
Speedometer evaluation?

Mine had a little sideplay in the input shell. very gently checked with a dial indicator.

And a lot in the drum (.020").