Series 2 mileometer

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vee12jag
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Series 2 mileometer

Post by vee12jag »

Hi all,
When I restored my 56 Series 2, I bought an NOS speedo (the correct one) from club spares.
Whilst the speedo works fine, the mileometer appears to record about twice the number of miles actually travelled.
Any ideas how to correct this? I am running the original 803, gearbox and rear end.
Thanks in advance.
Mark
jaekl
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Re: Series 2 mileometer

Post by jaekl »

That will do wonders for your fuel consumption calculations. Sounds like the worm drive for the mileometer pawl isn't correct.
don58van
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Re: Series 2 mileometer

Post by don58van »

Sounds like the worm drive for the mileometer pawl isn't correct.
I agree. If your speedo is reading correctly but the mileometer is way out, the drive for the latter must be the wrong spec.

Don
vee12jag
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Re: Series 2 mileometer

Post by vee12jag »

Thanks for the info guys. If the pawl is incorrect, how do I know what I need? Is it easy to change?
Thanks
Mark
don58van
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Re: Series 2 mileometer

Post by don58van »

I haven't tackled the early Minor speedo, but all the Smiths mechanical speedos are basically the same design.

I suggest that you search the web for 'Repairing Jaeger & Smiths Speedometers' by By:Anthony Rhodes. This is a well written and illustrated free document that has all the info you need, including an appendix that specifies the parts required to calibrate the tripmeter.

On the face of it, as yours is supposed to be NOS, it seems that the factory mismatched some components.

The tripmeter is driven by a number of components:
1) a worm drive on the input shaft
2) a gear that engages with it
3) a pawl moved by an offset drive which is driven by 2)
4) a gear that is moved one tooth at a time by the pawl

2) and/or 4) are the parts most likely to need to be exchanged for another. I suppose the replacements would have to be scavenged from another speedo.

I hope this helps.

Don
jaekl
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Re: Series 2 mileometer

Post by jaekl »

The worm gear that drives the pawl may be the wrong pitch/number of teeth. Check how well the driving and driven gear mesh. Removing it is obvious once you open it up. If the driven and the driving gears are a match set then the driving gear will need to be change as well. I've not had one of those off, but there should be a way.
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