10 replies to this topic

[DANTOO]

Hello all,

So my loom has a ballast resistor wire and so does my spare one. (pink and white).

If I'm using a newer performance coil, do I still need that wire fitted or do I need to change it out for a standard cable? I can't seem to find confirmation?

Can any one help?

Best regards :)

[nicklouse]

Is the coil for a ballast set up or not?

 

measure the resistance and see how it compares to the info in the FAQs

[Ethel]

Does the new coil say ballast or 9v?

 

If you can, measure the resistance between the + & - terminals (disconnect other stuff so you can't be measuring resistance in the loom).

 

Unballasted should be around 3ohms, ballasted 1.5ohms.

 

The ballast resistance makes up the other 1.5ohms to keep your points from melting.

 

 

Your Mini might have an unballasted white connector hiding in the loom, they did in the early 80s.

[DANTOO]

Hello there,

The coil is an Aidon Flame Thrower from Mini Spares. It states 3.0 ohms on the side.

So I'd assume I don't need that ballast wire?

Would it hurt if I left it in?

Regards,
Dan

[Tornado99]

The ballast setup helps with starting when battery volts are low (at lower temps for example) because it is bypassed during cranking, coil gets full 12v. Once running the feed to the coil goes back to the lower voltage (around 9v) from the ballast wire. This keeps coil temps lower and points contacts cleaner. If you no longer have points and you coil is 3 Ohm across the +/- terminals, then you're fine to run a new un-ballasted feed line direct off the "on with ign" fuse. 

 

However, my FlameThrower III Pertronix coil, with their electronic ignition, specifically states to run without a ballast feed line....and the coil is just 0.6 Ohm I believe. 

[Cooperman]

If there is one think you do not need, or want, on your Mini, it is that 'effing' pink and white wire.

The best thing to do it to simply remove it completely and use a norma white wire running to a 12 volt coil.

Twice I have had to re-wire the front loom after that pink/white wire has melted. When that happens it takes out the wiring for the headlights, sidelights, indicators, etc,. I know others who have also had this problem.

It's not quite so bad if you can do the re-wiring yourself, but the correct colour cables should be bought and used.

There is no need for a ballast resist coil as they were only fitted to Minis for a short while.

Be advised to remove the 9V rubbish and fit a good quality 12V coild and standard wiring.

[DANTOO]

Thanks for the response all. Sounds like a plan. :)

[ACDodd]

It’s always interesting the information given in forums ref 9 volt coils. People who advise to remove the 9 volt ballast coil and fit a 12 volt are basically reverting your car back to a time when ignition system needed no power higher in the rev range. People who give this advise are unaware of the reason for using a ballast setup in the first place. Later engines that turned higher rpm with higher compression ratios needed a constant energy ignition. The ballast resistor with 1.5ohm coil provides near constant energy in spark power right across the rev range with is something that the older 12volt 3 ohm coil symbols can’t do. The added benefit of Course is the ability to boost spark power when cold starting is also a boon!

You won’t ever find a Dodd built engine that uses Points without a ballast system fitted.

Ac

Edited by ACDodd, 17 April 2022 - 10:09 AM.

[DANTOO]

Hello Dodd,

Hope you're well

So should I keep the wire and 3 Ohm coil? It's Raj perfect ever since new 1380 has gone in and to Germany and back without missing a beat.

Dumb question? How does the voltage change depending on cold or warm engine?

Electrics are not my strong point.

[ACDodd]

You don’t use a 3ohm coil with a ballast resistor on points ignition. You change to a 1.5 ohm coil.

Cold start is provided by a feed from the cold start terminal on the solenoid (not to be mistaken for the starter motor output terminal!) this provides a battery feed to the positive of the coil. And thus by passes the ballast resistor and provides battery voltage to the coil under cranking. This ensures a full power strong spark giving quick easy starting.

Ac

[DANTOO]

Perfect. Makes sense! Been a while since I've had the engine in so trying to remember it all now. I'll switch to a 1.5 instead of changing out the wire