Tachometer conversion company in US

[gjz30075]

Does anyone in the US know of a good company that can convert an S3 tach from positive ground
to negative ground? Points will be used. I know about MoMa and Nisonger (whom no longer fixes
instruments, as far as I know).

[gsilvestri]

British Speedo Service https://www.britishspeedo.com

[elancoupe]

It’s been a few years, but I used West Valley Instruments in California, they converted to negative ground, and also for electronic dizzy.

[ElanDNA]

Does anyone in the US know of a good company that can convert an S3 tach from positive ground
to negative ground? Points will be used. I know about MoMa and Nisonger (whom no longer fixes
instruments, as far as I know).

Do it yourself. A few minutes of fear and it's done.
https://www.youtube.com/watch?v=ddZ0E2Wd6Ic

[steve lyle]

It’s been a few years, but I used West Valley Instruments in California, they converted to negative ground, and also for electronic dizzy.

West Valley did mine as well.

[gjz30075]

I like the options here. Thanks much everyone!

[billwill]

Does anyone in the US know of a good company that can convert an S3 tach from positive ground
to negative ground? Points will be used. I know about MoMa and Nisonger (whom no longer fixes
instruments, as far as I know).

Its a trivial alteration, just need to swap over the positive & negative wires inside the can.

Any hone electronics bloke could do it for you.

[steve lyle]

In addition to the polarity change, have the tach changed from current sensing to voltage sensing. Much more accurate, and quicker response. WV did this for me. If you go this route you also need to run a sensing wire from the - coil terminal to the tach.

[gjz30075]

Good points here. This tach is currently positive ground and set up for pertronix, whatever that means.
Sounds like West Valley for the win here.