I need a Positive earth tachometer

[lotsats]

I just looked at both tachs, and the one from India is a little different without a red line marker and the small writing at the bottom. It looks just like it belongs there, however. The first picture is the defective tach that came out of the car, and the second is the one from India. If you want to go to the copyright violation way, you can buy the tach in a package with an assortment of other “Smith’s” instruments for just slightly more money. My ‘66 Lotus 7 isn’t totally original, so I replaced the ammeter for a voltmeter use with the alternator conversion, and installed oil pressure and temperature gauges with a larger sweep of the needle. The car also now has a Lotus Twincam, Cortina rear axle, self made and better wiring harness in correct wire colors with more fuses and relays added, fuel gauge, stronge seatbelt mounts, bigger electric radiator, fan, and other items that make it, for me, an improved road car

[Timothy Keith-Lucas]

The positive earth tach from UK eBay has arrived and is installed and works. The only blip was that RVI "accessory" tachs do not ground through the case. They require a separate ground wire to the frame.  Thanks to everyone who has contributed to this thread. I have enjoyed and most importantly learned from the shared wisdom.

 

A very useful source for our tachs is "A Gentleman's Guide to Classic Smith's Electronic Tachometers" put out by the New Zealand Triumph Club as a PDF at

https://triumphclub.co.nz/wp-content/uploads/2025/01/A-gentlemans-guide-to-Smiths-tachometers.pdf

 

That's where I found the note that mine needed a ground separate of the case to frame.