MKIV Ignition Coil

Hello again,

I have an original Ignition coil for a MKIV but it’s not in working order. Does anyone know of anyone who restores / refurbishes original ignition coils? I don’t mind where the person or company is situated.

Cheers,
Tim

I have a NOS Lucas coil still wrapped up in it water proof paper seal. Absolutely no idea if it works as it’s never been unsealed.

I don’t know of anyone able to rebuild coils as I would say it is an art that died very early when replacement coils became cheaper than repairs. But I know what you mean by trying to retain the original look in all parts. I had a similar problem but the coil was fine. Surface corrosion had put a fine layer of oxide over the centre contact and the high voltage output could not break through to the HT lead.

It is worth doing a multimeter test on your coil before you condemn it to the display case. Unfortunately neither the Mk IV or V manuals give test data for ignition coils.

Primary Circuit: Set the meter to the low setting and contact the probes on the two outer terminals - the CB and SW or + and -. The reading should be under 5 Ohms. Many early Lucas coils had a small impression cast into the top cover noting the primary circuit resistance value, but you may have to look carefully on a very clean cover. Another model I tested, the Q12 for the 1.5L, was marked with 4 Ohms, and I would assume the B or BR12 for the bigger engines would be similar. As far as I know, 2 to 4 Ohms is normal.

Secondary Circuit: Set the meter to a higher range, +/- 10kOhms. Contact one probe on the centre terminal and the other on one of the primary circuit studs. The reading should be between 6kOhms and about 15kOhms. You can use either primary terminal for this and both should give the same reading. It would help if the original Lucas spec for these could be located so that you could be sure yours is in range. This static test may still not ensure satisfactory performance, as they can still falter under load or heat. They can become extremely hot if the internal resistance is excessive, indicating an internal fault in the windings.

Hi Tim,

I totally agree with you on keeping the original appearance.

Here’s more info on the coil construction:
http://www.da7c.co.uk/History%20Section/LUCAS%20ACHIVE/lucas%20coil%20course%203.pdf

Peter

Hello Peter,

Thank you for the information it’s really helpful. I’ve been offered an original coil by Ed - how wonderful is that? I have also been given an original, brand new battery for the MKIV - how wonderful is that? Someone else has offered me an original starter solenoid - how wonderful is that? I’m very fortunate to have so many wonderful people help me bring a rather unique car back to life. As an original Melbourne delivered car to be able to put it back to its original configuration and drive it around Melbourne is a special responsibility. I shall post photographs when it’s all complete.

However, my MKV bears more than a passing resemblance to your SS. The Cream in the photo is lighter than it is in normal light.

Cheers,
Tim

More power to your elbow on fostering originality!

Peter :muscle: :+1:

By the way, in my discussions with various people Martin Jay from the Distributor Doctor in the UK sells these coils which are fitted to millions of Indian taxis’s (large sample group) and he says are fantastic.

Holden UK sell this which is quite a nice looking period coil.
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Cheers,
Tim

The Holden coil does look pretty good.

Thanks,

Peter

The Indian Coil would suit XK engined cars, while the Holden pre-XK’s. I’ll buy one of the Holden Coils as a strategic spare.

Tim