Morris Minor Owners Club

What is your experience of replacement ignition coils?

I need to replace the coil on my electronic ignition-equipped, negative-earth 1275 with a Lucas DLB105 equivalent.

However, in age when many of the once-trusted brands are no longer what they were, I wondered if anyone had experience of these alternative makes of coil I’ve come across:

• Pride
• Viper (resin-filled dry coil)
• Remax
• Intermotor

Also, I note some suppliers offer their coils in ballast and non-ballast versions, but I’m unsure which I need for my set-up. Is anyone knowledgeable about car electrics able to explain?

I will explain the difference between a ballast and non-ballast systems.

Basically it comes down to primary coil resistance. When drawing current the coil usually tops out at about 4 Amps. This is sufficient to overheat (and destroy) a coil if the vehicle is left with the ignition on while the contact points are closed. Running any more current would also burn the points much more quickly, so a compromise situation.

For a 12 volt system the primary normally shows a resistance of about 3-4 Ohms. This may be just a coil or the coil plus an internal resistor.

Some vehicles were hard starters because the lower voltage at the coil (while the starter motor was operating) provided a reduced energy spark at the plugs. (Think here smaller batteries than in earlier years?).

The way round the problem was to fit a 6 Volt coil with a separate resistor (the ballast resistor) in the feed from the ignition switch.

The coil would normally be powered via this supply, whilst running - but when starting, the coil would be fed from the starter motor side of the starter solenoid, hence supplying a much higher coil voltage when cranking providing a better spark at cranking speeds.

Modern-day 12 volt coils are basically a 6 volt coil with an internal ‘ballast’ resistor within the coil canister.

If it's anything to do with ignition then I would speak to Distributor Doctor - http://www.distributordoctor.com/

Yes, I have had good service from "Doctor" Martin too. I bought a coil from him a few years ago and it has been fine.

I fitted a Bosch blue coil to my car in 2015 and it hasn't given me any trouble. I've also read other good reviews of the same.

Thanks everyone!