View single post by NigelK
 Posted: 09-09-2015 01:57 pm
PM Quote Reply Full Topic


Joined: 07-16-2014
Posts: 187
Hi Bill

The fundamental issue here is that the original Jensen-Healey Smiths tachometer is designed to be wired in series with the coil ("current triggered" or "RVI"). Compared to points, electronic ignition systems do not always generate sufficient current to trigger this style of tachometer.

I say "not always", because current triggered tachometers are reported to work with some electronic ignition systems, but not all. For example, when I switched my GT from points to Accuspark electronic ignition, the tachometer continued to work (albeit not very accurately). But when I changed to Lucas Constant Energy ignition, the tachometer stopped working.

More modern tachometers are designed to be wired in parallel with the coil ("voltage triggered" or RVC) and will always work with electronic ignition systems.

So while there may be several ways of getting your RVI tachometer to work with the Pertronix, the only guaranteed fix is to convert your tachometer to voltage triggered operation (Google "RVI to RVC conversion") and switch a couple of wires between the tachometer and the coil so they are wired in parallel. This is not as big a job as it sounds.

I used Spiyda Design in the UK to convert my original RVI tachometer to RVC operation, LotusBits fitted it and changed the wiring, and the tachometer now works fine while looking stock.

Hope this helps.

Best wishes,