General Generator to alternator conversion

[Vitesse]

I just had a look and the mounting studs are the same orientation, I can't see the tinwork being any problem? The problem will be if you don't have a spare mounting bracket for a Dynamo?

The Zelmot alternator has a built in bracket that is part of it and bolts directly onto the four bolts on the block.

The first picture is 650 tinwork and the last two are 500.

Surely doesn't it make more sense sticking an alternator in, if you are going to put the 650 lump in Murphio?

It's a straightforward job all you need to do is source an old voltage regulator that you can gut and use that as your junction box, so that you can swap engines without chopping any of the wiring about.

 

[fiat500]

Thanks Andrew and Tony. I'm going to have to start taking up these generous offers from people...I could end up making a spare car out of the bits.
But I do have a spare for both types as well as the dynamo bracket etc., it's just that the 500 one is in deep storage.
I can see that modifying for an alternator is easy and tidy and the arguments in favour of the alternator are irrefutable. But using this engine on my previously unmodified little Murf already involves more insidious little changes than I would prefer to make and the retention of my familar dynamo would please me. I'm going to "bench-test" the engine using the unrestored alternator simply as a mounting for the impeller. I might be able to do that later this week, but it will be a while before I try it in the car. So plenty of time to think about that.
I just wish I had the patience to produce such shiny objects as your engine Tony.:worship:

 

[fiat500]

Back to answer my own question; the alternator is shorter than the dynamo, therefore, in order to keep the pulley alignment, the centre dishing of the 126 front cowling must be shallower...less concave, in order to achieve this.

Incidentally having looked at all the dusty, rusty circuitry under the black cover of my alternator, I'm pretty certain I'm going with the simplicity of a dynamo.

 

[fiat500]

Back to answer my own question; the alternator is shorter than the dynamo, therefore, in order to keep the pulley alignment, the centre dishing of the 126 front cowling must be shallower...less concave, in order to achieve this.

...but I now think I am wrong as the alternator pulley fits with the two halves the opposite way round from the way it fits on the dynamo, which puts the centre-line of the belt in the same place despite the alternator being shorter.....clever Fiat as usual!

 

[LivG]

You need a slightly different bit of tin work where the alternator goes through to the air cooling fan. Slightly different stud width measurements. Easily welded / changed before repainting.

 

[Nowuries]

Hi Bambino:
I have found your posts super helpful as I rebuild my 1970. I am putting in a 700cc 126-based engine, and am setting up the wiring for the alternator, but am concerned I am putting my green wire in the wrong place. I looked at your picture and my alternator is wired differently. With the 4 prong attachment next to the regulator, I have a green wire on the top prong, a yellow wire on the right prong (closest to the regulator), a brown wire on the left prong (that comes from internal), and an open prong on the bottom. Do you think the open slot/prong is the right place to wire the (green) warning light, or is my alternator a different beast entirely?

 

[Uaglio]

Hi Bambino:
I have found your posts super helpful as I rebuild my 1970. I am putting in a 700cc 126-based engine, and am setting up the wiring for the alternator, but am concerned I am putting my green wire in the wrong place. I looked at your picture and my alternator is wired differently. With the 4 prong attachment next to the regulator, I have a green wire on the top prong, a yellow wire on the right prong (closest to the regulator), a brown wire on the left prong (that comes from internal), and an open prong on the bottom. Do you think the open slot/prong is the right place to wire the (green) warning light, or is my alternator a different beast entirely?

For what it's worth, here's a photo of how I am installing mine. The alternator had only one open male spade connector on the bottom of a 4 prong array, so I fitted the D+ wire (I believe from ignition) to it, using a 6.3 mm female spade quick connector and 12 AWG wire. The B+ lead (from battery) is labelled on the alternator cover and obvious (bolt style threaded connector; no wire attached yet in the photo), and the earth (ground) also appears obvious (large bolt connector on body of the alternator - in my case, I used new green 12 AWG wire). Not sure what that red "1" in a triangle signifies!

 

[Nowuries]

Thanks! It looks like yours is wired the same as mine, so I will run my indicator light to the open terminal/plug on the 4-prong setup. Thanks!

 

[Vitesse]

Thanks! It looks like yours is wired the same as mine, so I will run my indicator light to the open terminal/plug on the 4-prong setup. Thanks!

I have just checked mine for you and can confirm the open prong at the bottom is for the warning light wire.

Tony