Oh crap .. speedo jammed

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Mark Osterman
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Oh crap .. speedo jammed

Post by Mark Osterman » Wed Sep 04, 2019 12:16 pm

Driving to work this morning and going around 30 mph when I heard a faint clic .. and the speedometer registered 0. The chain broke of course but it wasn’t a chain problem ... the speedometer jammed. Couldn’t twist it with my fingers. It’s the second time it’s done this in a year. Am asking Russ about it via email but wondered if anyone else has had a similar problem with their speedometer.


Henry K. Lee
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Re: Oh crap .. speedo jammed

Post by Henry K. Lee » Wed Sep 04, 2019 12:30 pm

After spending a war chest, I just gave up! Tried various methods to resolve, Russ rebuilt 3 for Dad, they gave up the ghost too. The pot metal expands, locks up, and destroys the links. I just disconnect and drive with the flow.

Just my $.03 worth.ank

H


Topic author
Mark Osterman
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Re: Oh crap .. speedo jammed

Post by Mark Osterman » Wed Sep 04, 2019 12:39 pm

Sure, I get it. Russ rebuilt this unit due to that same expansion of a pot metal part. I drove it for about a year and it jammed. He kindly took it and adjusted it for free and it worked for another few months. I really like having it since I used the trip odometer as a fuel gauge. Also NY inspection does note the milage.


wayne sheldon
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Re: Oh crap .. speedo jammed

Post by wayne sheldon » Wed Sep 04, 2019 7:07 pm

Pot metal is funny stuff! (And I ain't laughing!) The accepted colloquial term "pot" metal comes from the fact that way back when, it was often a combination of this and that and whatever else got thrown into the "pot". Use of a fair amount of zinc and lead made it a good mix for easy pouring into molds for fairly small parts. Unfortunately, some materials were being used sometimes, that didn't alloy well, and in effect, poisoned the mix. It would take years before the effects became apparent, and most such parts were out of date and discarded by then. If it weren't for us crazies wanting to drive hundred year old cars it wouldn't be a problem at all.
But, here we are. The imprecise mixtures make predicting how individual parts will proceed to fail nearly impossible. The worst have long since crumbled. The best pieces may last for a couple hundred more years if kept out of the direct elements. In between, are some pieces that defy repair. They do not want to crumble, but neither do they want to stay put. Fix them, make them work well. But then they shift a few thousandths and jamb up again. Russ F is the best there is. But some pot metal just will NOT cooperate.

The only thing I can really suggest is to get another good looking unit and hope for better luck? If it needs some work done on it? I still say Russ F is the best!


Allan
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Re: Oh crap .. speedo jammed

Post by Allan » Wed Sep 04, 2019 7:18 pm

That is most likely the reason Duncan and Fraser here in Adelaide offered Corbin speedos on the cars they sold. These are a much better quality unit with a brass chassis. When I installed the one on my 1925 wide body roadster, all I did was clean out all the old grease in the cable and swivel and connect it up. The swivel too is cast steel, so they hold up well. The needle is super steady in operation, and at 35 mph on the dial I am doing 38 by GPS. I don't know whether to bother trying a different fibre gear.
The problem is Corbin speedos, usually 80 mph units, were used on early motorcycles, and those guys don't mind spending big bucks for them.

Allan from down under.


Topic author
Mark Osterman
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Re: Oh crap .. speedo jammed

Post by Mark Osterman » Thu Sep 05, 2019 8:23 am

Interesting. Do you have a picture of one of those Corbin speedometers on a mid 1920s dashboard?


Allan
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Re: Oh crap .. speedo jammed

Post by Allan » Thu Sep 05, 2019 8:53 am

Mark, my roadster has a polished blackwood dash as fitted to these custom built bodies, so is not typical. My first 1922 tourer had the hole in the panel, covered by a plate fixed with two screws, as the car was not fitted with a speedo. A friend who is presently in Europe, has a 1922 tourer with the Corbin speedo fitted. The dash on our Canadian sourced 1922 models is a flat, vertical, steel item. The hole for the speedo is cut entirely in the panel to the outer side of the steering column. The speedo head is retained by a flat U shaped bracket across the back of the unit and fixed to the dash with two metal threads. [The blanking plate on my first tourer was fixed using those same two holes] The speedo head is fitted through the front of dash so that the nickel plated bezel and bevelled glass sits proud of the panel.
The cable itself is a better made article too. Rather then continuous links of hardened wire like the Stewart offering, every second link is a solid casting. These cast links have an eye at each end for the wire links, but there are two raised ridges around the castings which act as bearings to support the cable in the housing.

I have a Stewart set-up for my 1924 Tarrant tourer, including a restored head from Russ, but I have not fitted it as yet.

Allan from down under.


Original Smith
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Re: Oh crap .. speedo jammed

Post by Original Smith » Thu Sep 05, 2019 10:27 am

I have a Stewart 160 in my '25. Russ did it too. It has never been a problem. I greased all the links a few months back, and the chain and housing were as clean as they were when I put the car together over 10 years ago. Perhaps you should think about changing brands of speedometers?

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