Cooper S Mk1 Rev counter & electronic ignition


  1. I have rebuilt a Mk1 Cooper 1275S 1967 and am trying to fit a rev counter. I changed to negative earth as I fitted an alternator. Previous owner had tacho fitted down by his feet! I took the wire, from the coil and fitted to the rev counter and connected an earth wire. That way, the car runs erratically and won't start as the tacho appears to take the spark away. I'm not sure the tacho is a neg earth one. Is there any way of telling? Can abyone advise on wiring and if there's a way of identifying the tacho being pos or neg? Tacho is old Lucas one, ignition is Lumenition Magnetronic.

  2. imported post

    The configuration you have won't work. The early smiths counters wont work with electronic ignition. If you are unlucky you could have damaged both tacho & ignition pack.


    You'll find some info here that should help.

    Mark F.

  3. imported post


    Long time no hear from. Wish everything was working as well as the SUs you overhauled for me so nice to have contact again. As the rev counter now seems unable to exceed 3,000rpm, I probably have damaged it. But it was probably a positive earth one so no good to me. Shame though. Hope the electronic ignition is OK. Without the tacho wired, it seems to run fine. Would you suggest the Smiths tacho as sold by Mini Spares or the Tim, much cheaper one, to work with electronic ignition? Wiring diagram much appreciated.

  4. imported post

    Hi David,

    I did wonder if this was you when I posted the reply, it is good to hear from you again too!

    The modern Smiths ones work fine with electronic ignition, and if the ignition pack is still working OK with the tacho not connected, it will be fine.

    There is a very good article on Smiths Tachos here, not mini, but they are all the same in the end.


    Good luck,

    Mark F.

  5. imported post

    Hi David

    Had the same problem with a 1071 I ran with lumenition – I burned out the ignition in one key stroke – it melted. Sent off for another. Have you thought of buying a new Smiths one from minispares and having Speedy Cables swap the face/needle and lens so your new one looks like an old'un? worked for me.


  6. imported post

    hi! your web site is truly amazing, and i was wondering if you can help me. I have a 1965 Austin cooper with only 23 000 km from new, the car is in incredible fresh condition and completly authentic. I have purchase an old 1964 smiths rev counter as i did not find a speedwell. Now i'm looking for a nice speedwell POD to fit my revcounter. Do you have an idea where i can find one?
    many thanks, regards!

  7. imported post

    Hi just come across you notes . I had the same problem when I bought my S in that the car had been set up for neg earth and I only had a mx reading of 3000 approx . I ended up send 2 tacho's away for repair to an excellent company – highly recommended see his web site [url=][/url]which details the price . Contact number is 01 535 672125 . Regards Bruce[font=Arial][size=5][/size][/font]


  8. imported post


    Thanks for info but, when I went into the website you suggested, I couldn't find an address. Is it in the UK or the USA? My repaired tacho only reads to 4500rpm or so so I would like to get it fixed. Do you know where the company you dealt with is based? I would much appreciate it if you would let me know.

    David M Ross

  9. imported post

    He is in the Uk and I spoke to him am today .

    Regards Bruce

    [b][font=Arial][size=3]J D O Instrument Engrs
    [/size][/font][/b][font=Arial][size=3]34 Spring Avenue
    [/size][/font][font=Arial][size=3]West Yorkshire
    [/size][/font][font=Arial][size=3]BD21 4UG
    [/size][size=3]EnglandTelephone : 01535 672125[color=#bbbbbb].[/color][/size][size=3] ( + 44 1535 672125 )
    Fax :[color=#0000ff]# [/color][color=#bbbbbb]… [/color]01535 * * * * * * ( + 44 1535 * * * * * *[/size][size=3] )
    Mobile / SMS :[color=#bbbbbb].[/color][/size][size=3]07831 886545 ( UK Orange )
    [/size][size=3]e-mail :[/size][][u][color=#0000ff][size=3] [/size][/color][/u][/url][size=3][url=mailto:john_ostick@hotmail]john_ostick@hotmail[/url][/size][size=6][size=5][/size][/size][/font]



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