The alternator is from a Ford Transit – the type with the brake servo pump attachment on the rear. I got my recon units off eBay for about £45 each.
First of all the car must be changed to negative earth. This is not a major problem but if you have an original clock in your rev counter I am not sure if this will change to negative earth, without doing it damage.
1. I used the standard TD pulley without the cooling fan ring. I have not tried the TC pulley with the integral fan ring, so I do not know if the shaft on the Alternator is long enough.
It is necessary to make the hole in the pulley larger to become a nice snug fit over the shaft.
2. It is necessary to remove the 3 long bolts which hold the alternator together and twist the front plate of the alternator to get the adjusting bracket hole in the correct position.
(it must be in the same position as the dynamo you take off)
3. Next, depending on which type of alternator you have, you must make sure that the wiring connections are on the rear face of the alternator. It is sometimes necessary to remove the plastic connection block and modify the connections/insulator. This is to give you enough clearance between the engine and alternator and allow you to use the standard fan belt.
4. The shaft that protrudes out from the rear of the alternator needs to be shortened by about 20mm. I cut mine off with an angle grinder because the shaft is hardened.
5. You need a 50mm long distance piece with an 8mm hole in the centre to make a spacer for the rear mounting point of the alternator.
The next item you must modify is the rev counter gearbox.
1. You need to remove the 2 screws (or sometimes they are rivets which need to be drilled out), to separate the casing where the gears are. Then fit a spacer over the screws inside the gearbox. This is because when you make and fit the bracket to the gearbox you can tighten the screws; then it does not squash the casing on to the gears and seize the gears.
I removed the knurled nut which tightened the gearbox to the dynamo and made a coupling from steel bar, but I think it would be possible to use a piece of rubber or plastic hose. That way it would be easier to make, and it would also allow a little flex if the gearbox was not aligned correctly
2. Fit the bracket to the gearbox using just 1 of the screws. I made the bracket from a piece of 15mm wide by 3mm flat bar.
3. On the rear of the alternator there are 3 threaded 6mm holes which were the mounting positions for the pump on the Transit. I used the top outer hole to screw in a piece of 6mm threaded rod and the other end of the threaded rod goes through the bracket you have made and fixed to the gearbox.
4. Push one end of your coupling over the alternator and the other end over the rev counter gearbox. My coupling is about 30mm long you then adjust the gearbox until it is running true in the centre of the alternator.
5. I carried out the simple wiring change by visiting the MGA guru web site, where there is a very good explanation on how to convert the wiring. www.mgaguru.com/mgtech/electric
Moss part number for the TD pulley 433660 Ford alternator part no 5030668 or Lucas exchange part no. LRA 780.
The usual disclaimer applies that I accept no responsibility for anything whatsoever, and that anyone considering or intending to carry out this modification should be confident in their own minds that they are able.
I have carried out this mod on both my TC and TD and it has been very successful. It is a joy to drive with halogen headlights on, wipers going and the heater on if necessary, without having to keep looking at the amp meter worrying if the electric is going to dry up and vanish.