how do you convert from a dynamo to alternator on an 1960s car?

Question

im back again with my 1964 super minx the dynamo seems to have stopped workin red charge light is now on constant and the battery is dead had battery checked and its fine is it a hard job to convert to alternator or can you still buy bushes to repair dynamo as someone told me it could be bushes that have burnt out

Answer 1

If you wish to convert to an alternator and your vehicle is positive earth then you will have to use an isolated return alternator (expensive!)

In my experience you are better sticking with the dynamo, here are some pointers:

1 - Is the commutator dirty - clean it with some fine emery
2 - Are the brushes worn or sticking - either replace or clean
3 - Are the contacts in the regulator dirty - take the top off the regulator box and draw a piece of fine wet and dry between the points, followed by drawing a piece of stiff card dampened with WD40 through them.
4 - does the dynamo need re-polarising - this is the one most people forget about. To start your dynamo going it relies on residual magentism in the core, if this has decayed it will not work. To re-polarise for a positive earth system then disconnect the wires at the back of the dynamo (D+ and F), take a piece of wire from the battery negative and touch onto the F terminal (you will get a spark and this is good), re-connect the wires and you are done. If it is negative earth then use the battery positive.

Hope this is of help.

Answer 2

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Answer 3

Changing the system is very simple. The hardest thing is to get the alternator bolted on with the right brackets, and lined up with the drive pulley(s)! Now If you want to use Lucas ("prince of darkenss") electrical system, you might have a couple things to do, such as is the voltage regulator separate form the alternator or not? The Lucas in my MGB is built in regulator, and very simple hookup! Most later alternators have the regulator built in. All you have to do is have a heavier wire going from the alternator to the battery (output), - since the alternator will put out a whole lot more current, and could "fry" the one the generator used! You will need a wire providing power from the ignition system in "run" position, to the "f" terminal (field)-- - (although you could get by,- just wiring hot from output connection on alternator too, - most marine applications use this method with no ill effects). Put one on my brothers Fordson Dexta diesel tractor 15 years ago, (Was a delco from Chevrolet), no problems so far!! The second wire on the alternator "plug" is for the "idiot light", (and system will charge fine with this wire disconnected even). Hopefully this car has a ampmeter, - which should work ok (provided it is in the circuit to battery from alternator) -and it is high enough capacity to read what the alternator can put out! You can look at just about any typical alternator circuit and figure out pretty easily how it will have to be wired! Since the generator wiring is very similar, you should be able to figure it out!!

Answer 4

Renovating a dynamo is a lot simpler and cheaper than converting to an alternator. New bushes (if available) are quite easy to fit and will prolong the life of the dynamo for a long time.

Answer 5

In my opinion it is a lot easier to fix the dynamo or regulator than to install an alternator. The most likely cause would be worn dynamo brushes. That is easy if you know how. Have you a workshop
manual????????? The main regulator problem is dirty contacts
Remember to disconnect the battery.!! Don't adjust anything unless you know what you are doing.

Answer 6

Unless you are a car sparks i would not try if i was you . i have converted them, but you do have to know what you are doing if not you could have a fire on your hands , yes you can get brushes for them but you may be able to have your own reconditioned , you may have the proplem that it is not the dynamo but the cut out box its a square black plastic box about 7x5 inches look inside and see if the points need cleaning there are two sets inside , in the old days they very often burnt out

Answer 7

Some Vintage car specialists supply an alternator which looks like a dynamo and simply fits in its place.
Look in the MG car pages.
RoyS

Answer 8

You need a Lucas 17ACR alternator. That is the correct device for a Mini. Take a look at the link below for more detailed information.

By the way, I love BARROWMAN's advice to change the 'bushes' in your dynamo, and his nonsense advice in general... he's obviously an armchair mechanic.

Answer 9

1964 Hillman Minx , remember it well .
Just one thought though ,I seem to recollect they used Positive earth on those ,In that case it would be Very dodgy to fit an alternator.
It can be done if its negative earth ,as the regulator is built in, just connect via a 80 amp fuse direct to the battery.
I would have tried for brushes ,that's the easiest job.

Answer 10

More than likely the dynamo bushes have gone, I should think that motor factors would still have replacements, They are dead easy to replace.