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Speedo Question

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Ohiobugeye

Ohiobugeye

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Hi all.After 7 years my Bugeye is finally on the road. My speedometer is reading way to fast, Both speed and mileage are almost doubled. My engine is a 1275 and the transmission is a rib case. The speedometer is a mechanical Smiths sn 6144 / 100 1040 . Not sure if this unit is compatible with the midget rib case transmission could it be from a MG B or another similar car?
 
An original Bugeye (MPH) speedo would be the following:

6155/10 1472

The one you have is from an MGB
 
I am guessing that the correction ratio is 1472/1040 so your speedo/odo is reading 41% too high. (?)
BillM
 
Don't know if you can do it with an MGB speedo, but with prior problems such as this I've taken mine to a specialty speedo shop where they recalibrated it. They will want to know the final drive (or at least the number of tire rotations per given distance).
 
Boink said:
Don't know if you can do it with an MGB speedo, but with prior problems such as this I've taken mine to a specialty speedo shop where they recalibrated it. They will want to know the final drive (or at least the number of tire rotations per given distance).
Click to expand...

I think the innards are pretty much interchangeable parts, so it may very well be possible by changing out the gears. I don't think it could be re-calibrated in terms of adjusting what's there.
 
If you had all the parts to convert both the odometer and the analog speedometer... you would already have the Bugeye speedometer you need.

If you send this to a speedometer shop for rebuild and conversion it will cost a bunch and it still won't be original to your car (if originality matters to you). You can look for other Smiths speedometers with 1472 turns-per-mile as Gerard said OR you can fit a ratio box.

Contact the folks at ATP (gaugeguys.com) and tell them what you have and what you need. The can build you a little gearbox that goes inline with the speedometer cable. It will take that 1472 cable RPM and drop it to the 1040 your existing gauge needs. They will have to charge you for a new speedometer cable (that they will modify for the box) and of course they charge for the gearbox itself. Still... it will be less expensive than converting the MGB gauge to read correctly.

For a better explanation, visit their web site:
https://www.gaugeguys.com/
Click on the link at the bottom left for "speed correction"
 
Why not just find an original on flea-bay?? That would appear to be the cheapest route to me. I have a nearly new original around here somewhere i may be able to part with. [if I can find it]


Kurt.
 
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