Had a quick look when I got home. Tried to start her and she fired up! However, there was a loud clicking noise (best I can describe it) from the distributor. So turned off and popped the disi cap off. I seem to have a lot of up and down movement of the shaft - more than I think there should be. I would guess about 3 to 4 mm (0.11 to 0.16 in).

Am I correct? Is this too much movement? Should there be any? It is a Lucas 25D.

Up and down movement? That seems a bit odd. The drive dog has shim washers to minimize the up/down freeplay of the shaft relative to the housing.

The 4-lobe cam is a separate part held onto the main dizzy spindle by a phillips head screw. Remove the rotor and you may or may not find a felt pad in the center of the 4-lobe cam. If you see the felt, pull it out and you should see the center screw. Tighten that screw and see if you still have motion up and down. You really shouldn't have much motion when that screw is tight.

If after tightening the screw you still have axial play in the dizzy I'd pull it out and go completely through it to see where it's coming from. I'm not sure how it would be related to your surging problem and it really should have no bearing on the headlights getting brighter or dimmer, but it's certainly something I would look at.

Thanks Doug!
Your advice has been really helpful!
Will keep you posted.

That screw could not be tightened anymore. So distributor was pulled and sent for repair. Will let you know when it is back - what the synopsis was.

Distributor was repaired. They also bench tested it for me and found that the spark was not strong enough. Distributor was converted to electronic ignition about 4 months ago. Everything is working - the issue seems to be the ballast that Lumenition say must be in place. Without the ballast - spark is good. With ballast spark is poor.

Question: Can I run a Lumenition Magnetronic system without the ballast? Or with this damage the module?

Distributor was repaired. They also bench tested it for me and found that the spark was not strong enough. Distributor was converted to electronic ignition about 4 months ago. Everything is working - the issue seems to be the ballast that Lumenition say must be in place. Without the ballast - spark is good. With ballast spark is poor.

Question: Can I run a Lumenition Magnetronic system without the ballast? Or will this damage the module?

Lumenition is stuff I have not worked on. You may want to put posts about this in the Spridget and MG forums. The Mini, the Spridgets, and the MGB all use the same series of Lucas distributors so you're likely to find someone who can answer this there. Meanwhile, I'll post your question on a U.K. board I frequent since Lumenition is more common over there.

Can you type a bit of the Lumenition instructions that discuss the ballast? Typically the ignition system is expecting a total series resistance of some value. If you're using a low-resistance coil a ballast resistor is often added to bring the total resistance back in line.

Interim Post:

Humor me by telling me some more about your car without my having to re-read the previous three pages of posts. What year is your Mini? What ignition is on the car (Lumenition Optronic with the optical chopper, or Magnetronic with the Hall Effect sensor)? What wires are on each coil terminal?

Please review the following.
(Optronic Lumenition)
http://www.lowflying.dk/images/PMA50ins.pdf
SUITABLE FOR coils or coil/ballast combinations of not less than 3 ohms.
NOT SUITABLE FOR use with low resistance (i.e. less than 1ohm) electronic ignition coils

(Magnetronic Lumenition)
http://www.lumenition.com/new/support/magign/mtk003_instructions_v1-3.pdf
No mention of ballast requirement

Some Minis in the early 1970s did have a ballast ignition system. Typically these had a pink/white resistor wire from the ignition switch to coil (+). They also had a yellow/white wire between the starter solenoid and coil (+). Does any of this sound like your car?

The notes on the Optronic kit are really important to interpret correctly. Note that they say your TOTAL series resistance (ballast + coil) should be 3 Ohms. This does not mean you necessarily have to run a ballast.

Write back and tell me a bit more about your car, its coil wiring, the coil you've fitted, and whether or not you've got a multimeter. If not... it's time to buy one.

Hi Doug

You are quire right! I checked the insructions at home and when I did the install I misinterpreted the diagram to "have to include" the ballast. It is not necessary - unless it was previously ballasted. It is the magnetronic system.

The coil fitted is the Lumenition specced ans supplied coil. Coil was tested and is still strong.

It is a 1000cc Mini station wagon - 1968. There is no ballast wire. I do have a multimeter.

Hope I have answered all your questions. Its now time to get the distributor back in the car and back to the original problem - the reason for this lengthy thread!

I'm not familiar with Lumenition's coils. However, with NO wires connected to it, use your multimeter to measure across its low tension terminals. If you find close to 3 Ohms... you're golden and don't need the ballast.

This may be why the car refused to start last week. If you have a 3 Ohm coil and you added a ballast resistor in series with it, the amount of current flowing through the coil will be significantly reduced. This would be true at highway speeds also. Even though you say the misfire happened with points... test drive the car for a while without the ballast resistor and see if it's better.

Hi Doug

I got 2.85ohms on measure. So hooked everything up - with new ignition leads - and with the first turn of the key she fired up - having stood for a week!

I will let you know if the original problem is still there - but for now she is running sweetly.

Thanks for all your help.

2.85 Ohms is basically a standard coil. You'll have a much hotter spark now without that additional ballast resistor.

After you've driven the car for a few days be sure and post back and let us know how it's running.

I have driven the car now for 5 days or so and the original problem has not recurred! Yahoo!! However, I have noticed that the difference between the brightness of the headlights at idle and above 1000 rpm is substantially different. Last night I drove through a rain shower - I had the headlights on and the wipers going. The wipers were quick while running and slow while idling - again a substantial difference.

I have had the car at an auto sparky twice. He is adamant that the alternator is not overcharging - said I would now if it was as the battery would start to give of a sulphorous smell.

This normal? Any advice? You think I am just being paranoid?

Well, you say it's running better and that is the good news.

I have a couple of suggestions for you that will be interesting little side projects.

First, either buy a new volt gauge or look for a nice used one on eBay. Look for VDO if you can find it (not Smiths). The VDO gauge will respond quickly to changes in voltage while the Smiths has VERY slow response. Once that's wired in, glance at it periodically while you're driving... particularly when you notice the headlights dimming. It might just be a minor fluctuation in the car's operating voltage that is the issue. However, you'd really like to see the car's charging system operating at 1V to 1.5V over what the battery shows with the engine off. You do not want to see alternator output higher than about 14.5V

The other project that may help with the headlights (possible... but harder on the wipers) will be to make and install a headlight relay panel. There are kits out there for this but you can easily make your own using Bosch/ISO relays. These relays are regularly available at auto parts stores and online from surplus companies like bgmicro.com. The advantage of adding the relay panels is that the supply to the lamps is more direct through low resistance contacts. Most people report consistently brighter headlights with relays installed. The relays also take the load off your dash wiring and standard headlight switch. This extends the life of those parts.

Thanks Doug.

I have already put my headlights onto relays. So the switch activates the relay and pulls the juice directly off the battery as opposed to through the switch. I have also upgraded my headlights to take a modern H4 fitting and I am running 60/55 xenon globes. The lights on my Mini are excellent - I would venture to say as good as my late model BMW.

I will take your advice and put in a volt gauge. Will get back to you and let you know.