Replacing Distributor

[Stuey7]

Hi,

About 12 years ago we replaced the dynamo with an alternator on my 1962 948cc Minor. I have bought a new distributor with electronic ignition built into it. I recall that when we replcaed the dynamo we had to disconnect one of the wires from the distributor. The new one has a red and a black wire and I don't know which one to connect to the coil and which one to disgard. Can anyone advise me please as I don't want to damage the disributor by connecting the wrong one?

Thanks

Stuart
No 2099

[svenedin]

Hi,

About 12 years ago we replaced the dynamo with an alternator on my 1962 948cc Minor. I have bought a new distributor with electronic ignition built into it. I recall that when we replcaed the dynamo we had to disconnect one of the wires from the distributor. The new one has a red and a black wire and I don't know which one to connect to the coil and which one to disgard. Can anyone advise me please as I don't want to damage the disributor by connecting the wrong one?

Thanks

Stuart
No 2099

Switching from a dynamo to an alternator may have required you to switch the polarity of your car from the original positive earth to negative earth. This is because all modern alternators are negative earth. I cannot be certain that this is what you did because it is possible your car had already been changed to negative earth when it still had a dynamo.

Assuming you switched polarity to negative earth you would have had to have switched the connections round on the ignition coil. The standard connections are:

Modern coils are marked + and -. Older coils are marked CB and SW

Positive earth coil connections: CB (contact breaker, points) or + goes to the distributor. This is a white wire with a black trace. SW (switch) or - goes to the ignition switch. This is a plain white wire

Negative earth coil connections: The reverse of the above. CB + goes to the white ignition wire. SW - goes to the distributor wire, white with black trace.

Check your coil is wired correctly for negative earth and then follow the instructions provided with your electronic distributor. Both wires from the electronic distributor will need to be connected.

IF it is an Accuspark module

Usually the red wire from the electronic distributor AND the plain white wire from the ignition connects to the + terminal of the coil

The black wire from the electronic distributor connects to the - terminal of coil.

The white with black trace wire that originally went from the coil to the points distributor is redundant.

Switching from points ignition to electronic ignition is likely to require small changes to the ignition timing for optimum performance.

Stephen

[Stuey7]

Thanks Stephen,

I switched the car to negative earth about 30 yers ago to fit a radio and a clock. The coil is fine, I ordered a new one the same time as the distributor and fitted it this morning, the engine then ran OK.

It's not an Accuspark distributor, I got it from David Manners. Its looks like a standard 25D with a rotor arm and some sort of electronic sensor in place of the points and condenser. Unfortunately it didn't come with any instructions so any advice gratefully received.The red wire is much longer than the black one so I suspect this is the one that goes to the coil, the black is much shorter so may be an earth.

Stuart

[svenedin]

Hello Stuart,

Do you have a link to the electronic distributor you bought?

I would strongly advise against making educated guesses about how to connect it up. Electronic modules usually fail almost instantaneously if incorrect polarity is applied

I had a look at DMG and I did find an electronic ignition kit for the Lucas 25D4. It looks to me like a Pertronix Ignitor which is also sold under the brand Aldon.

Have a look and see if your module inside the distributor looks like an Aldon or Pertronix Ignitor (they are the same thing). https://pertronixbrands.com/products/pe ... zQCSYXCi3V

If yes then:

https://cdn.shopify.com/s/files/1/0247/ ... U-142A.pdf

Stephen

[Stuey7]

Hi again Stephen,

I don't have a link and it came in a plain brown cardboard box. I will email David Manners to ask for instructions and/or a wiring diagram.

Regards

Stuart

[svenedin]

Hi again Stephen,

I don't have a link and it came in a plain brown cardboard box. I will email David Manners to ask for instructions and/or a wiring diagram.

Regards

Stuart

OK that's the best idea unless you can positively identify who made the module inside.

Stephen

[Stuey7]

Hi Stephen,

Just wanted to say "thank you" for your help. I got a wiring diagram from David Manners, it was just a case of black to negative and red to positive on the coil, I was wary of doing this without checking as the originl distributer only had the red wire. Anyway, fitted the new coil and distributer and starts and runs fine.

Cheers

Stuart

[svenedin]

Thank you, much appreciated and glad to hear it’s all working.

Stephen