Technical 1972 850 Spider Sport Alternator Question

[tinindian68]

Hi all,

I recently purchased a 72 Spider Sport and I absolutely love it! I'm having a problem with the charging system at the moment.

From what I'm reading a 72 model would/should be equipped with an alternator. Well, my 72 is equipped with a generator. I'm sure a generator will work as long as the connections and relays match, but I'm not sure what I have here. Voltage at the battery hovers right at 12.6v at idle and picks up just a bit when revved (12.7-12.8).

First, I want to make sure I have the right parts, and if possible get the stock parts charging as they should.

If it's not worth the trouble, I'd like to put together a reliable charging system. I have a few GM internally regulated alternators around, but I'm not sure if this is the best choice due to size.

I'm happy to provide any additional pictures, if needed.

Thanks!
Brian

 

[timmycm850]

72 should gave alternator but your images show dynamo.

The dynamo if working should give out upto 17v and the regulator stopping it going over or bear to that.

Alternator would give out upto 14.4v but many more amps than the dyno.

Do you have access to any alternators from cinquecento or seicento 900 as they are a close fit and have build in regulators. I've used a cinquecento one on my 73 spyder for near on 20 years with no fuss but you will need a pulley from an 850 alternator and machine it to fit.

Tim

 

[tinindian68]

Thanks Tim! I found a few Cinquecento alternators on eBay. It looks like that would be the most straightforward setup. You wouldn't happen to have a schematic for how you dealt with the wiring changes?

Brian

 

[timmycm850]

Sadly my brain can't remember that far back. But I think its just one wire from the dashboard light but I may have had to fit a relay under the dash for some reason.
And the main output lead straight to the 12v main lead on the starter.

Note the cinque one is a single pulley and you will need a double so it can feed the waterpump. I think I had to flip round the waterpump pulley a bit to get it to line up
Tim

 

[tinindian68]

Sadly my brain can't remember that far back. But I think its just one wire from the dashboard light but I may have had to fit a relay under the dash for some reason.
And the main output lead straight to the 12v main lead on the starter.

Note the cinque one is a single pulley and you will need a double so it can feed the waterpump. I think I had to flip round the waterpump pulley a bit to get it to line up
Tim

Thanks again. This is super helpful. This is my first Italian car and I love it, but I'm a bit out of my depth on parts compatibility.
Brian

 

[timmycm850]

Hi Brian
There's lost of parts crossovers with other models before and after so you can do a lot with other car parts from otger Fiat models

 

[tinindian68]

Quick follow up. I was able to purchase a rebuilt Cinquecento alternator on eBay. It took a few weeks to get to the US but bolted right on without any issue. I used a dual pulley from a General Motors alternator. I was able to remove the regulator and the alternator relay in the engine compartment and clean up a bunch of wiring. One wire to power (at the starter) and the other to the alternator warning light and it was good to go.

I did have to flip the water pump pulley around to make everything line up and get a shorter belt but I’m back on the road!

Thanks again, Tim for the tip!

 

[timmycm850]

always try to help keep these cars on the road