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Help with correct coil.

Discussion in 'Electrics' started by gavking, Mar 4, 2018.

  1. gavking

    gavking New Member

    I have been working on the engine mainly rebuilding carbs etc. Rover p6 2000tc 1973. Once rebuilt I couldn't get the car to start and found the spark to be very weak,
    I have tried to test the coil with a mutlimeter but it is giving readings that are bouncing all over the place.
    So i thought buy a new coil as they are cheap enough and this is where the problems start. The car chassis number has a B suffix and the engine has an A suffix. The coil is marked Ballasted but the ignition has been upgraded to electronic. I am under the impression a B suffix car should have a ballasted coil.

    The car ran fine with a Ballasted coil before I stripped the carbs last year but now I don't now what coil to buy as there seems to be a lot of changes from original.

    Anyone be able too give me some advise on what to buy?

    Thanks for any help in advance as usual.
  2. harveyp6

    harveyp6 Well-Known Member

    AFAIK electronic systems don't use ballasted coils.

    Just to add to that, if the car ran a ballasted system then it should have been fitted with a 12v coil when the electronic ignition system was fitted, and that would have meant bypassing the ballast resistor. If that wasn't done then you would have been getting the reduced voltage at the coil when running, and if that is case then fitting a 12v coil wont improve things, so check the LT voltage at the coil before you start and see what you've got.
    Last edited: Mar 4, 2018
  3. gavking

    gavking New Member

    Yeah I was wondering if I should buy the 12 volt coil and bypass the resister. I can’t check the old coil as I’m getting poor or erratic readings hence the thought of buying a new coil. So I take it I should do the bypass and standard coil conversion then?
  4. harveyp6

    harveyp6 Well-Known Member

    I'd check what voltage you have at the coil with the ignition on first.
  5. roverp480

    roverp480 Active Member

    Lucas Ballasted coil should have a resistance of 1.3-1.5 ohms and a 12v 3.0-3.5 ohms between the two low tension connectors.
  6. gavking

    gavking New Member

    Thanks for your help Harvey. Its throwing down with rain at the moment so i will do as soon as it dries up a bit.
  7. Willy Eckerslyke

    Willy Eckerslyke Well-Known Member

    When I fitted Pertronix electronic ignition the instructions included were clear and easy to follow - with different wiring depending whether the coil was ballasted or not. My 1974 2000TC does have a ballasted coil which I retained. But, as this means the +ve feed to it is 6v, the Pertronix unit had to be fed from elsewhere. I wired it into the heater blower loom chosen because it's easily accessible and switched by the ignition.
  8. gavking

    gavking New Member

    Thanks for the help so far. Im gona wait until it dries up a bit before going out and taking a good look at it. They joys of Electronics ! :)

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