Speedometer test

[WPVT]

I have a Stewart Warner speedometer in a 1929 White truck. After I replace the broken cable, I'd like to test the speedometer without running the vehicle. How fast does the cable normally turn, and which direction ?

 The speedometer is free and looks to be in good shape. 

I don't want to harm the speedometer, or check the accuracy, just see if it works.

Thanks. 

[Ltc4748]

You can turn the cable between your fingers and watch which way makes the needle move upward. Then take an old speedometer gear if you have one and chuck it in a drill to run it faster or put the cable in the chuck and tighten the check only enough to hold the cable.

[WPVT]

Thanks. Good suggestions. I have new inner cable material on the way, and I hope to drill out and then reuse and re-crimp the original cable ends. Once I've got the new cable, I'll take the speedometer for a "spin". 

 

[Guest]

Resources - FAQs - Detail - Auto Meter

 

https://www.autometer.com › resources › index › faq_view

The speedometer is calibrated for a 1:1 drive ratio (1,000 RPM at 60 MPH input at the speedometer head.) If the vehicle tire size and/or rear end differential are not stock, a different driven gear in the transmission may be required for speedometer accuracy.

 

Remember Google is your friend.  I searched for "speedometer cable rpm" and had this information in .39 seconds.

Edited January 2, 2020 by Guest (see edit history)

[WPVT]

Thanks. So I don't need to spin it that fast to get a result at the speedometer head.

Is a new inner cable inside an old housing necessarily a bad idea ?   I'm sure the cable broke for a reason.  

The original inner cable is .130". I found a source for this, but all of the replacement ends I've found are for .187" cable. So I'm going to try and re-use the ends, drilling them out and re-crimping. I suppose if that fails I can replace both the cable and the housing and use .187" inner cable. Maybe I can even use the .187 in my existing housing.  

 

[Guest]

Drilling the ends out works fine.  Usually lack of lubrication causes a cable to break although a seized head can do the same.  When you install your new cable just lube the bottom third of it.  One year back in the 60's I broke three cables in one year, still do not know why.  The last replacement has lasted 350,000+ miles.  I have been pulling it out once a year (10-12K miles) and it still works fine.In the last 40 years I have picked up three spares but have not needed them.

[JACK M]

Or seized odometer.

When you get it spinning the hint would be a clicking noise.

[WPVT]

1 hour ago, Tinindian said:

Drilling the ends out works fine.  Usually lack of lubrication causes a cable to break although a seized head can do the same.  When you install your new cable just lube the bottom third of it.  One year back in the 60's I broke three cables in one year, still do not know why.  The last replacement has lasted 350,000+ miles.  I have been pulling it out once a year (10-12K miles) and it still works fine.In the last 40 years I have picked up three spares but have not needed them.

Thanks. I did one end by cutting off the crimp and old cable and re-drilling. Drilling out the old cable didn't work since it is hardened spring steel, and the end is mid steel. The drill bit finds the path of least resistance. 

Why only the bottom third? 

[Guest]

30 minutes ago, WPVT said:

Why only the bottom third? 

First it is what is recommended in many shop/operator manuals.

Second it is recommended because the lube works upwards and if it gets into the speedometer head then you really do have a problem.

Lubriplate Chain and cable or 105 or soft cup grease works fine.

 

WD-40 is not good to use, It was/is designed to be a water dispersant not a lubricant and makes a poor to good penetrant.  If you believe otherwise, use it on your bicycle chain and leave it parked outside in the rain for a few days.

Edited January 2, 2020 by Guest (see edit history)

[WPVT]

9 minutes ago, Tinindian said:

First it is what is recommended in many shop/operator manuals.

Second it is recommended because the lube works upwards and if it gets into the speedometer head then you really do have a problem.

Lubriplate Chain and cable or 105 or soft cup grease works fine.

 

WD-40 is not good to use, It was/is designed to be a water dispersant not a lubricant and makes a poor to good penetrant.  If you believe otherwise, use it on your bicycle chain and leave it parked outside in the rain for a few days.

Thanks. That makes sense. You obviously know what you are talking about.

So now I am trying to figure out how to get the old cable out of the speedometer cable end. The transmission end had enough material to cut the crimped section off and re-drill. This one is shorter. Drilling out spring wound cable can't possibly go well. I tried pulling out the inner section, but it's three layers of spring wire, and there's no pulling out the center or the outside layers. Pretty amazing really when you think of all the technology that went into all these parts. The old cable end even has a tiny "Stewart" logo engraved into it. 

[WPVT]

I'm going to try heating the cable end to see if that will allow me to pull the remaining stub of the cable out of the crimped end. If that fails, it may anneal the cable wire sufficiently to allow me to attempt drilling it out. 

[bob staehle]

WPVT

As you found out those cables are twisted together. make sure you put the twist in the right direction so it does't unravel from the rotation.

I would look around for a 2nd or 3rd generation repair shop, see if they still have the ends and tools to crimp and swage the cable.

                   good luck Bob

[WPVT]

Thanks. I found my choices limited, so I'm going with the only .130" cable I could buy, regardless of the "lay" of the outer wind. I've found the wind on the old cable to be very tight, with the 3 layers alternating in their direction. It would take an awful lot of force to unwind the cable, from what I can see. If there is that much torque, there is a significant problem.

Crimping is not a problem, as I have the necessary dies, etc. Once I get the old cable out of the cable end, things should be pretty straightforward.