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Gauge Conversion Project

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dklawson

dklawson

Yoda
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I'm always tinkering with gauges. It's a passion.

15 years ago we picked up my wife's Triumph-GT6 from her father as a restoration project. None of the gauges worked. At that time I swore that there had to be a better way than to rebuild the original instruments. My resources were limited at that time so I paid to have the speedometer professionally rebuilt and calibrated. However, I never lost sight of my desire to have modern instruments for the GT6.

I have now completed part of that project. I have finished my electronic upgrade of an original Smiths speedo. The converted gauge turned out much better than I had ever hoped. I'm not sure when I'll install the gauge as the rebuilt stock unit is working fine but I'm tickled to death over this conversion.

It's an early 1990s VDO aftermarket speedometer whose works have been transplanted behind the Smiths face. The cool thing about VDO is you can independently calibrate the pulses/mile and the sweep of the analog needle. I've bench calibrated the unit and it's "dead nuts" accurate and rock steady. Next I'll try and figure out how to best do this with my Mini Speedo.

This is why I posted earlier this week about locating a used 4.1" [104mm] chrome bezel for Spitfire/GT6 gauges. I'd like matching bezels on my converted tach and converted speedo.

See pictures at:
https://home.mindspring.com/~purlawson/pictures/
 
Doug,
This is great information and provides hope for those of us with struggling instruments. Why don't you put together details of your project and include it in the knowledgebase.
 
I have a PDF document I wrote about converting tachometers. That can often be done with common hand and power tools. The speedo conversion requires machining some parts. I may put together a document about the speedo conversion but it may not be useful to readers unless they have access to a milling machine.

I conceived my project before having access to the internet. During the past couple of years I've noticed that Palo Alto speedometer routinely does conversions like this for Porsche owners. It would be nice to have similar options (at a lower price) for LBCs.
 
I'm planning on converting my TR2 temperature, rev counter and possibly speedo to electronic versions, if you could provide any words of advice I'd greatly appreciate it!

I've so far only thought about the temperature gauge, and plan to take the innards out of a modern Smiths gauge - I think only minor modifications are needed to the old gauges face.

The rev counter is problematic due to its scale (0-6000rpm). Any ideas?

My other plan is going to be modifying the ammeter, so that only a very small current passes through it, but its total scale will be -60 -> +60 amps, (using a current clamp style idea).
 
The tach can be done by a few companies around. You then need to configure the dizzy to be elec from direct drive.
 
WillE, as DNK said, the tachometer is probably going to be your easiest project apart from the temperature gauge swap. I documented some of my tach conversion work in a PDF you can download from:
https://home.mindspring.com/~purlawson/files/

If you want to write me about the speedometer conversion, feel free to contact me at: dklawson-at-mindspring-dot-com.

The Ammeter conversion you're talking about sounds like a shunt type meter and I've never worked with them. I decided to use only volt meters in my cars.

If you install a later temperature gauge movement in your early gauge, keep in mind that the later style gauges use a bimetallic heating strip. The gauge is usually matched to a specific series of sending unit so make sure you buy both at the same time (i.e., buy an MGB sending unit and its matching temp gauge at the same time). These bimetallic gauges used the voltage stabilizer to operate on a fixed 10v. You can install a Smiths stabilizer OR put in a solid state regulator to power the gauge. I also have an article on voltage stabilizers at the link above.

It sounds like you've got a really exciting project. Do let me know how yours turns out and feel free to contact me.
 
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