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Auto-electical newbie - Lucas Ignition coil

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  • Auto-electical newbie - Lucas Ignition coil

    I've a 2000ish Caterham with a xFlow. Recently left the ignition on and I think I've killed the battery (PC925). My battery tender claims it's charged but it barely turns the engine over and the starter is chattering. Also no lights on the dash. Anyway, while trying all this I noticed that the Lucas ignition coil is getting seriously hot, to the point that touching it for more than a second of two would likely burn my fingers. Did I damage the coil by leaving the ignition on? Is it likely that I damaged anything else in the ignition circuit? Also didn't realize that Lucus coils were liguid filled?

    Help this amateur out please....


  • #2
    Ok, second stupid question, now that I've got the coil off the car I didn't make note of which wires went where and I see that the two outer terminals on the coil are labelled + and -. Anyone got a Caterham wiring diagram? One connector has two white wires, the other has a white wire and a white/black wire. Thanks.


    • #3
      Does the car have a distributor with points? If so the points may be toast.

      How to determine which wire is which? Measure the voltage at the wires once you get the battery recharged with the switch on, one will be either +6V or +12V. (points type ignition systems drop the voltage thru the points with a big resistor) Connect that one to the + Terminal. A continuity tester may tell you which is ground too. Another way to check is the negative terminal goes to the distributor / points to complete the circuit to the coil. Google ignition coil wiring.

      The resistor is to drop the voltage to 6 volts as the points will last a lot longer with the lower voltage. If it has the pointless distributor I am not sure it matters what the voltage is. If it has points you may be able to convert it to pointless.

      With an Odyssey type Gel Cell, when discharged deeply they must be recharged with a charger that provides at least 6 AMPs of current. The typical trickle charge will not bring them to full charge.

      The one thing that will ruin them is being kept at a high state of discharge for any length of time. Try to recharge at the 6 AMPs or more and maybe it will be OK. Maybe not.

      As for the coil, you'll have to test it to see if you get spark.

      If you start a fire, it's not my fault.

      Feel free to call Doug at Eight Zero Five 402-1225.


      • #4
        Thanks for the pointers, I'm working this weekend but may have a few minutes to spare in the garage.