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Discussion Starter #1
I have a late spider/Milano "one wire" internal regulated alternator that I want to install in my '72 Super which has a odd (for the US anyway) Ducellier external regulated alternator.

OK, here's my problem:

The Ducellier has 3 separate wires: a red battery wire at the Bat+ connection, a green wire at the D+ connection , and a black wire at the DF connection.

The new alternator (see photo--not mine) has a B+ connector for the red battery wire, a D+ connector and a + connector for a resister.

How can wire my new alternator so that it will put out the alternator light?
 

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Jim,

If you mean how do you wire this in principle, then the alternator light has one side connected to a switched ignition supply (generally in the fuse box), the other side of the light is connected to the recessed spade terminal D+.

If you mean how do you it for your car in particular, then this is a bit of a guess.
The oldest circuit that I have is for an early Alfetta with an external regulator.
This shows that the alternator light is connected to ignition in the fuse box, and the other side with a Green wire to the D+ connector on the regulator. For this Alfetta it should just be a case of relocating the Green wire down to the D+ connector on the alternator.

I don't know how 'standard' Alfa were with colour codes between models, but a quick look at the circuit diagram should show how closely this circuit matches your car.

Hope this is of some help.
Alan.
 

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We've done this several times in our shop. Since the new alternator is internally regulated, simply hook up the large RED wire to the B+ stud and the smaller GREEN wire to the D+ spade. The black wire went to the external regulator and isn't necessary.
This is a simple and very worthwhile conversion. It also works in older 105 cars that originally had generators. RED to battery and Green to idiot light.(Sometimes the idiot light wire is more bluish)
 

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Discussion Starter #4
Thanks for the help. I asked this because, although there was a lot of talk about making the change on the BB, I didn't come up with any specifics about the actual wiring. Obviously, the hook-up was so dead simple that the writers didn't even think it worth mentioning.

I'm glad we finally have a post on this. Now, there'll be instructions for those of us who tend to ignore the obvious.
 

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Alternator

Hi
I remember doing it the first time; it seemed too easy and felt that there must be something I was missing. Just make sure that the battery is disconnected during the swap to avoid shorting out the red wire on the alternator case.
 

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Yeah, it is pretty easy as Paugnut1275 said. I've got exactly this in my Super and can snap a picture if you have any issues. It would have to be this weekend though as I'm away from the car right now.

Kevin
 

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Discussion Starter #7 (Edited)
It Works!

Simply put, hook up the green wire (which puts out the alt. light with the alt. is charging) to the D+ spade on the one-wire alternator, connect the red wire from the battery to it's lug and you're in business.

However all did not go quite as easily as I expected. Although I expected my Rock Auto alternator to be a rebuilt Bosch, it turned to be a clone made by US Industries. Since it was cheap enough and looked more or less oem, rather than send it back I decided to fit it and see how it worked.

It fit perfectly . . . except for one small problem. When I fitted the fan-belt the alternator's pulley was about 1/4in out of alignment with the water pump pulley. Not good. That's a guaranteed way to shorten the life of your water pump. The obvious cause is that the pulleys on the late spiders are positioned a bit differently than the pulleys on my 1.3 Super. To get everything in alignment I removed the fitted pulley and fan and substituted the pulley/fan from an older 3 wire Bosch alternator. Fortunately all the parts exchange perfectly. You'll also want to use the woodruff key from the Bosch alternator; for some reason US Industries didn't use a woodruff key. The slot is on the shaft, however.

Be careful tightening things down because it's easy to distort the sheet metal fan causing it to rub against the alternator housing.

As mentioned earlier, the wiring part is dead simple. Just find the green wire at the alternator connection, bypass the voltage regulator, and splice it to the green wire coming from the instrument panel. You can tape off or remove the black wires since all you need now is the single green wire connected to the D+ on the alternator.

Now I have a more powerful alternator that also puts out the red light on the dash.
 

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The AlfaBB does it again! I never had an ignition light on my Spider, saw a D+ terminal on the back of the alternator (with nothing attached!) and a quick search came up with this thread, six years later!!

What a terrific. valuable, resource it is.
 

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Guys I used this post to help with my alternator installation but its not working as it should... Ie the dash generator light remains on and when the engine is running it is only putting out 12.5 volts vs 14volts?

Previous system had a separate regulator which I have bi passed.. Green wire direct from the dash to the D+

Any thoughts on what next to check? should I have the alternator grounded?

Thanks for any help..
image001.jpg
 

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Thanks for the reply.... Now you have me thinking.. I replaced the dash lights with LEDs a few years ago... can't remember if I changed the alt light.... That could cause the issue?


Any chance you replaced the alternator light with an LED? My understanding is that these alternators need the higher resistance incandescent bulb. Otherwise the regulator needs higher RPM to kick on the alternator.
 

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The alt light does need to be incandescent, yes.
Agree with Gubi. With a conventional, incandescent bulb, the alternator will begin charging as soon as the engine starts. But as gprocket wrote, even with an LED bulb (or no bulb) the alternator will start once it reaches a high enough RPM. My point being that if Rooony's alternator isn't charging under any conditions, then it's probably more than just the light bulb. gprocket's "pull the battery cable" test would be a good next step.
 

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Thanks.. Yes I have pulled the cable and the car stalls.... Also tested with a meter and there is no increase in output when the car is running... Can the alternator be tested off the car?

I've just put the original back in with the separate regulator and all is working fine...

I like the built in regulator as it is less cluttered in the engine bay..

Could it be that I have not revved it enough to kick in? any other thoughts?

Thanks



T
Agree with Gubi. With a conventional, incandescent bulb, the alternator will begin charging as soon as the engine starts. But as gprocket wrote, even with an LED bulb (or no bulb) the alternator will start once it reaches a high enough RPM. My point being that if Rooony's alternator isn't charging under any conditions, then it's probably more than just the light bulb. gprocket's "pull the battery cable" test would be a good next step.
 

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Places like Pep Boys and Autozone can do a free basic test for alternators or you could take it to an alternator specialist and they can test it. I agree with the need for an incandescent bulb. I made that mistake when we were pruning the wiring harness in our race car Milano!

Kevin
 

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Could it be that I have not revved it enough to kick in?
Beats me - I wasn't there when you revved it. But you don't need to take it to 7,000 rpm - 3,000 ought to do it.

any other thoughts?
Do what kredden suggests and take it in for testing. Most likely, it's something internal to the alternator.
 

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A correctly connected and working alternator on a 105 Alfa will generate full load amps at around 2000 engine rpm.
 

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I didnt have an ignition light for ages, but the alternator worked fine, so I'm not sure that the light is relevant.
 
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