Non-Fiat Alternator

[Greg500]

Hi all,

I need a new alternator for my Spider. I want to upgrade but more importantly I want to replce it with an alternator that is more readily available at a local parts store. I don't mind building or modifying a bracket but I am not confident on how to wire another alternator. I have seen a gm alternator being used in a few posts but nothing on how to wire it. Any help would be greatly appreciated.

Thanks,
Greg

[ORFORD2004]

Why don't you buy the 95 Amps? and if one day you got problems, any alternator shop will be able to rebuilt it.

[Odoyle]

Look for a Bosch 65 amp alternator, or a generic equivalent, I can't recommend using a 95 amp alternator as the PO installed one in my 79 and melted parts of the harness.

[DieselSpider]

Oreilly has both the 55 Amp Marelli and the 65 Amp Bosch for less than $70 and both are Lifetime Warrantied. Your existing one though can likely be rebuilt by any local AutoElectric who rebuilds alternators and starters. You would be surprised at how easily obtainable parts for older Fiats are when you walk into a real parts store and have the manager look things up for you and at how inexpensive they are too.

[geospider]

I tried recently at O'reily and there were more than 20 on back order. Autozone only had 55 amp.
Went to Napa and got a rebuilt Bosch 65 amp in 1 day for $50.

needed the old pulley, but he swapped them for me.

great little store

geo

[DieselSpider]

I tried recently at O'reily and there were more than 20 on back order. Autozone only had 55 amp.
Went to Napa and got a rebuilt Bosch 65 amp in 1 day for $50.

needed the old pulley, but he swapped them for me.

great little store

geo

Like I said shop around locally and you'd be surprised how easy parts can be to find if your speaking to the right man behind the counter (not the guy who if he can't find it in the main catalog in 30 seconds gives up and sends you packing).

Go to a local rebuilder and most will have it rebuilt better than new in a day or two.

[Greg500]

Thanks for all of the replies. I ordered the O'Reilly alternator and they called me the next day to tell me they were no longer available. I am sure they get them from the same place as most of the other part stores.
Here is what happened. I was over in Biloxi durring Cruising the Coast with my wife enjoying all of the classic cars and just cruising when my battery light came on. Now I know you typically have about 50 miles to get to where you need to go and I was further than that from home. I went tho AutoZone and they checked the alternator and it was bad. Luckily I am retired military and Keesler AFB was close so I left the car their over night. If AutoZone would have had the alternator in stock I could have fixed it then. My Spider is my every day driver. I put an average of 110 miles on it per day and I love my car too much to leave on side of the road until a part comes in. This is why I am switching to an alternator that I can get anywhere at any time.

I am currently in the process of building a bracket to fit a 78 amp alternator from an 85 S10. I am just not sure if I need to add any kind of resistor to keep from burning up my wiring.

Thanks

[spider2081]

I too am a fan of the original Bosch alternators being simple and inexpensive to repair. I realize not everyone is going to have access to a parts place or repair place close to them. I have been lucky in that respect.

I am currently in the process of building a bracket to fit a 78 amp alternator from an 85 S10. I am just not sure if I need to add any kind of resistor to keep from burning up my wiring.

An alternator only supplies the current that it is asked for. So in most cases the original wire sizes in your car should be fine. The one wire I question is the alternator output wire that connects the alternator to the battery cable at stater solenoid. This is a #10 wire on many Spiders. I have seen this wires insulation melted off on a number of Spiders with stock alternators. I think the alternator can put out too much current for this wire if the battery is dead and the car is jump started. This then causes the insulation to melt. I am pretty sure if a diode in the alternator were to short the current flowing from the battery then could melt the wire. In any case I like to replace this wire with a #6 wire. Many street rod parts places supply a larger output wire with their higher current retro alternator kits.

There are pro's and con's about keeping the electrical systems as stock as possible. This is especially true for future maintenance. Keeping records sure would help in the future. So I would keep a wire diagram of your final installation and PN of the alternator used.

In case you change your mind: https://www.mirafiori.com/forum/viewtop ... 18&t=97455

[RRoller123]

Thanks, Spider2081, that is good advice, and another relatively simple upgrade will be added to the list! Do you trust a standard Fast-On type connector/crimp at each end or do you solder these connections? A #6 could be somewhat troublesome to get a good solder joint with, may need a torch and some full RA flux, which then would need cleaning.

[spider2081]

I have access to professional crimpers as well as terminals used in aviation industry. So I do trust them. I would not trust the type that you strike with a hammer or use in a vice. The handle on the crimper is about 30 inches long and crimps makes a square shaped cpimp on all sides of the connector. WalMart carries a 19" #6 cable for lawn and garden equipment with crimped ends on it.

https://www.walmart.com/ip/Everstart-LG ... s/16006699
I think the terminals are for a 5/16 stud. Its a simple solution.

I would not solder terminals used on wire sizes larger than #8

[RRoller123]

+1. Thanks, that is excellent information. I used something similar for a second engine ground. Should have thought of it for the alternator too.

[geospider]

Check on a Napa near you. ordered Wednesday afternoon and picked it up on Friday; noon.
They all do have different suppliers in my experience.

or as Dieselspider suggested; take yours to an auto-elec shop and have them rebuild it

[Greg500]

Spider2081, Thanks for the advice. I will definitely upgrade my battery wire but 19"s will not reach my trunk. Not sure if the battery was originally in the trunk but it looks stock. I don't think I am going to change my mind mostly due to all of the bickering I read on many forums of what Spider alternator is best. I know the GM alternator is reliable and plentiful and I am too deep into the project to turn back now. I do however, keep very thorough records on my vehicles. I use to be an aircraft mechanic when I was in the USAF so I guess I am a little OCD about maintenance records now.

[spider2081]

Spider2081, Thanks for the advice. I will definitely upgrade my battery wire but 19"

The wire I'm talking about is the wire that connects the alternator output to the battery cable. The battery cable is plenty large enough for the length and current. The battery cable is routed from the battery + to the starter solenoid. The wire I'm talking about connects the battery cable end at he starter solenoid to the alternator. So I think 19" is long enough.

[Greg500]

I was just rereading your post and realized that. It is nice to get technical advice instead of opinion. Thanks again.