Speedo cable question

[steve meltzer]

I hope it's OK to post this question here, as I've great respect for the help I've gotten in this forum. (and it is a 427 SO!). Speedo cable on my Kirkham broke early this past summer. Little green painted gear in the tranny, OK. All put back together and I rerouted the cable so it only has very wide angled bends. Finally got to drive the car and the speedo worked fine, but shortly thereafter, it died.

The speedo itself (Autometer) runs CCW, I was going to disconnect it at the tranny, and, if it looked OK, spin it with a drill to see if I can isolate the problem. Make sense? Which way would I spin the drill? I might have to disconnect it at the speedo head to see. Thoughts? Thanx. Happy Turkey Day. steve

[wrench87]

There should be a little reverse unit that mounts to the speedo, you have to remove it and clean and lube it.
I read somewhere that the cable ends are a little to long and when you tighten the cable it binds up and doesnt move freely, some have cut a tiny bit off the end so it does not bind.

[patrickt]

Originally Posted by steve meltzer

I hope it's OK to post this question here, as I've great respect for the help I've gotten in this forum. (and it is a 427 SO!). Speedo cable on my Kirkham broke early this past summer. Little green painted gear in the tranny, OK. All put back together and I rerouted the cable so it only has very wide angled bends. Finally got to drive the car and the speedo worked fine, but shortly thereafter, it died.

The speedo itself (Autometer) runs CCW, I was going to disconnect it at the tranny, and, if it looked OK, spin it with a drill to see if I can isolate the problem. Make sense? Which way would I spin the drill? I might have to disconnect it at the speedo head to see. Thoughts? Thanx. Happy Turkey Day. steve

You want to put your drill in to REVERSE when you spin it. Here, read this thread: Lubricating the Smiths Speedometer Cable To Stop Needle Bounce Even though I have a Smiths, everything still holds true for Autometers.

[wrench87]

I was thinking about this, it was not the cable end but the stub inside of the reverse unit that was to long and would bind if tightened to much.

[patrickt]

It is always either:

1) the driven gear in the transmission;
2) a crack in the cable or debris in the cable causing friction;
3) a kink in the cable from too tight a curve;
4) the length of the inner cable going in to the reverser is too long;
5) the length of the drive shaft between the reverser and the speedometer is too long;
6) binding within the reverser from a lack of lubrication or malfunction;
7) the speedometer gears binding.

If the speedometer has ever worked right, then it is not going to be 4 or 5. If no changes have been made to the cable routing, then it's not going to be 3. You can diagnose 2, 3, 6 and 7 by reaching under the dash, disconnecting the cable and reverser and then spinning the cable with your fingers and spinning the speedometer by hand with the short driven shaft and then spinning the reverser by hand with the shaft. Spotting a problem with 1 requires visually inspecting the gear itself.

[rodneym]

What would make a cabke twist like a pretzel? Binding?

[patrickt]

Originally Posted by rodneym

What would make a cable twist like a pretzel?

A craving for mustard.

[Bernica]

In case you are also tinkering with speedo accuracy, here is the limited knowledge I can offer...

[rodneym]

Originally Posted by patrickt

A craving for mustard.

Jamo,
Please revoke 5,000 posts from patrickt's count for this joke.
It's that bad.

Bernica,
Recently I saw an article or post online with a graph showing how the teeth affect mph, depending on a couple variables, of course. I can't find it now but it's out there. That way there's no messy mathmadix.

[Bernica]

Try this calculator. Or just google "Ford Speedometer Gears"

Speedometer Gear Calculator and Charts - TCI® Auto

[patrickt]

Bernica's calculator requires brains. Here, Rodney... use this simple chart instead. And if you lube your cable with mustard, make sure it's the spicy brown kind, not the yellow stuff.

[rodneym]

That's a nice chart.

Spicey mustard has too many things in it.
Equal parts of lithium grease, trans fluid and good 'ol French's.
These graphite lubes are for wussies.

[Bernica]

Interesting they don't list the "J code" orange tip gear for the toploader that I show in the pic.

[patrickt]

Originally Posted by Bernica

Interesting they don't list the "J code" orange tip gear for the toploader that I show in the pic.

I ripped that from ERA's site. I don't think Bob & Peter would let you put a 3.07 or numerically smaller rear in one of their Cobras anyway.

[sllib]

Steve;
I had to shorten the drive on my reverser. It broke the cable just testing the speedo with a drill. Replaced the cable, good to go.
Bill