Speedo cable

[CaptRandy]

66 Sprite; the speedo cable jumps around while driving not giving a real indication of speed. Could this be a lack of lubrication of the cable to the back of the speedo? If so would a spray lubricatan like Corrosion X solve the problem?

 

[nomad]

Cant hurt! I like to pull the cable and soak it in a pan of engine oil for a while.

Kurt.

 

[Jim_Gruber]

Or you could do as I did on Bugsy I and build your own digital speedo using a Sigma Wired bicycle cyclometer. A 180 mph readout capability and project with all parts and pieces <$50. I attached display to mirror mount bracket and works almost like a Heads Up display as it is always in your field of vision. An interesting engineering project to be sure.

 

[Jim_Gruber]

Oh and dead nuts accurate on speed as speedo is calibrated to wheel rotation. Button magnet JB welded to rear drum that triggers a reed switch works great. Ping me if interested in details.

 

[Gerard]

66 Sprite; the speedo cable jumps around while driving not giving a real indication of speed. Could this be a lack of lubrication of the cable to the back of the speedo? If so would a spray lubricatan like Corrosion X solve the problem?

It could be the cable, but it could also be an issue in the speedo itself, either lubrication or the proximity of the magnet to the needle. They can sometimes come too close to each other and even slightly touch.

 

[Boink]

I had the same experience with a big Healey, and it was a chafing cable requiring lubrications (though not much).

EDIT: I remember using that bouncing as a defence to a cop that pulled me over for speeding. I used to think I could go with the average of the bounce... but that wasn't what he said.

 

[urchin]

My '66 Corvair's speedometer started jumping around and eventually screeching at times. I bought a tube of graphite lubricant on the mainland [Carquest parts guy: " I remember that stuff. I think we have one on a shelf somewhere." I got the only one on the shelf.]. I sprayed it in the cable and it worked fine. Liquid Wrench makes a spray can of "dry lubricant." I used that in the cable of my '66 Land Rover and it cured the jumping. Once in a great while it's the speedometer itself, but most of the time, I've just had to lubricate the cables.

Jeff

 

[Pythias]

The bad news is that while you can try lubing the cable, odd are that the plastic gear is worn out in the tranny. Try the easy thing, but be prepared to either live with it or get ready to pull the tranny for a rebuild. ... sorry....

 

[CaptRandy]

I think I will start with Corrosion X on cable and in the head. Move to more drastic measures as results occur.