Ballast resistors .... and do I need one?

[george]

As most people know I am restoring my previous 2L turboed Twin Cam back to original (as near as practical).

Previously ran a $600 plus Inition Developments system (no contact breaker, modern small coil) with a fully stuffed about with wiring loom. This caused probs with tacho and some sort of module was added.

I have since sourced a new wiring loom from 1300GT (only hassle is this ran a generator, but is untouched by fools and has the correct firewall plugs and switches etc.) Plan is to use this with a pertronix breakerless system and a Lucas high energy sports coil (gold with green sticker). A new original tacho has also been sourced.

Apart from above, everything else electrically will be standard.

Today in preparation for replacement of the steering column, I found a small silver block on the bracket that mounts the steering column. It is labled Lucas 4BR and looks like a resistor and is burnt out.

Is this the infamous Ballast Resistor that I have often heard about but never actual seen one (or actually new where it would be).I'm not sure exactly what it does, but I guess that its the sort of resistor that varies with temp.

So, do I need to run this or was this something that was required with 1970's coils. If I dont need one, what mod do I need to make to the wiring loom? If I do need one, has anyone got one?

George

[joe84]

i think the ballast resistor you talk of is a pink wire (looks thick on the outside but has stuff all strands inside) that's about a metre long and runs up and down .. connects about 200mm from the firewall.. gives you 12volts cranking then backs off to 9v. i had this prob with my elec ign as i only put the multimetre on with the ignition switched on and it showed 12v so thought i didn't have that wire in although when it started was back to 9v after fixing it improved idle significantly

[george]

OK, I'll take a piccy tommorow.
The thing I'm talking about is a galved steel stip (approx 70x25mm) that is bent to a very flat C shape. It has a brass spade connector and looks like an earthing lug, but on the otherside is a flat resistor. It look like a very large strain gauge if you are familiar with them and its made from very thin metal (nichrome?). Below this is a thin mica type layer and then a piece of strip alumimium (heatsink).
As mentioned it has 4BR Lucas, made in England and 47212B and 1870 on it.
George

[jsa]

George,

It is made by Lucas, first rule give it the flotation test

Will wait to see pic before commenting on it.

As to the need for ballast resistor, that will depend on the electronic ignition you are going to use, if it requires one then use one, if not then use the right coil for the electronic ignition without a ballast resistor.

[george]

John,
OK, not sure at the moment.
Say I need one, are replacement ballast resistors available, because chances of finding a lucas one are slim.
If I don't need one, what do I do with the loose cable?
George

[jsa]

[george]

[Craig]

[george]

[george]

[Craig]

[jsa]