Mk 2 Stag, Rev counters and electronic ignition problems but now solved.

[Robin Searle]

I have a 1972 US Stag,recently purchased and found that the electronic rev counter did not work. I had Rimmers rebuild it and still no luck,so I tried a loaner and still same but then I was loaned one that worked 100%. Rather than ship my "bum" one to the UK,I googled Smiths Tachs and came up with Nisonger in NY.They had a listing and explanation of why my Tachs did not work,I recognized the lettering in black ink on the working loaner from their picture in the explanation article.Smith tachs and electronic ignitions do not talk to each other,and need a new circuit board installed to enable them to work.A fact that did not seem to be known to all that I spoke to including the Stag owner who loaned me the one that worked So my frustration of the past 6 months has now been looked after and I look forward to 2012 with a working tach

[V Mad]

A 1972 car will probably have the early tachometer fitted. These work on a current impulse are known to be incompatible with electronic igntions. The later Mk2 units which work on a voltage impulse do seem to work ok with electronic ignition. If you know how to do it you can modify the Mk1 tachos to work like a Mk2.

[wilf]

I had a similar issue on another vehicle and had to pay Speedy Cables to alter my tacho - is it not just the insertion of a capacitor that is required? Can anyone here properly describe the modification that is needed? Electronic ignition would most certainly be on the list of "needed modifications" when I eventually find "my" Stag.

[V Mad]

Yes, more or less. I think its just a matter of bypassing the pulse transformer and instead, connecting the signal from the distributor to the input via a capacitor.

I am sure Alan knows exactly how to do it and will be happy to explain.

[SGN]

When I got my stag the rev counter didn't work.
It's a 73 Mk2 and has piranha (newtronic) ignition.
I can't remember where I got the info from, but I had to run one separate wire from the coil to the rear of the rev counter.
I won't be able to check for a week or so which terminals were connected, but it works no problem now.
Sorry to be a bit vague.

Cheers
Steve

[Robin Searle]

Thanks to all for your replies. Steve I tried direct feeds from the coil,voltage stabilizer and to ground ,but it just sat there.Glad that I googled,as Alan Davis was away when I emailed him twice,so I needed answers before putting her to bed for the winter,[ minus 30C at times here] $700 plus later in total costs all along I should be up and running for 2012.

Regards
Robin