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MG MGA - Electronic tachometer

Hi all, I am looking for some advice please. I would prefer an electric tachometer say from an MGB to use in my negative earth car.
Any thoughts on which type? Must be possible I got confused reading Barney's account I dont mind altering the loom to suit.
I have my reasons to not stick with the cable version.
Any advice appreciated.
M Dollimore

I used one out of a 68 Sprite and had the face from the cable driven tachometer fitted.
Bolney Coupe

when I installed my 5-bearing MGB engine into my MGA I had to fit a negative earth electronic Tacho as I couldn't use the mechanical rev counter any more.

I bought a Smiths RVC 2415/00AF tachometer from ebay and it worked perfectly with my electronic ignition.

This model Tacho is the unit fitted to the later negative earth MGBs I believe.

It looks pretty similar to the original MGA tacho, except that it has the Smiths logo on the dial instead of Jaeger and the boss in the centre of the needle is slightly different. You have to look carefully at the tacho to notice though.

Also, if you also have electronic ignition on your engine, remember DON'T take the power supply for the new electronic tacho from the coil terminal, but instead, take it from another ignition controlled source.

Taking the power supply directly from the coil can cause the tachometer to exhibit some very erratic readings.


Colyn Firth

Hi Mark,
If you send your mechanical drive rev counter to Robert Fenn he will put an electronic module into your existing MGA rev counter



I had a MGA tacho face printed and installed onto an RVC tacho - the only giveaway is that the fixing screws are in a different position.

I also have a custom speedo face - MGA Jaeger face printed onto a Triumph Spitfire guts, with three warning lights - FOG (for the driving-lights-on indication), OIL (light is connected to a pressure switch mounted into a modified union between the flex pipe and rigid pipe by the starter switch) and the standard IGNITION light. This gauge was made to my spec by Richard Jenkins as an apology for the multiple balls-up he had made of my previous speedo. It works very nicely and is calibrated for my 5-sped gearbox.

I know that the OIL light is a duplication of the dual gauge, but I look at the speedo / tacho much more than the dual gauge, and the OIL warning light is much more attention-attracting if there is an issue.

I also have a tiny yellow LED in the fuel gauge as a low-fuel indicator for when I finally get the Gauge Wizard calibrated properly
Dominic Clancy

I installed a second hand MGB tacho in my A b/c it has an Austin A60 block with no mech drive.
Unfortunately it reads zero rpm all the time. My thinking is I got the sensor wound the wrong wat so it is trying to read backwards. Any suggestions welcome!
Both car and tach are neg ground.
Art Pearse

Thank you all for your comments it would appear there are a number of options I'll do some exploring- thanks Mark
M Dollimore

This thread was discussed between 21/03/2021 and 25/03/2021

MG MGA index

This thread is from the archive. The Live MG MGA BBS is active now.