Non-Fiat Alternator

[Greg500]

I am finished with retrofitting a GM alternator to my 1981 Fiat Spider and everything is working great.

I will post a writeup on how I did it if anyone is interested.

[Greg500]

This post is to outline how I retrofitted a GM alternator to my 1981 Fiat Spider. The alternator is 78 amp from a 1985 S10 but is found on a lot of other GM vehicles. The reason I choose this particular alternator is because I read a lot of forums that say that the 65 amp alternator is not enough and the 95 amp would melt wiring so I settled for something in between and also wanted an alternator that would keep up with a 2500cfm fan, A/C and I can find at any parts store.

1. I lined up the existing alternator with the new one.


2. Fabricated a forward and aft bracket and drilled the holes about 1 ¾” apart to allow room for the oil filter housing and brace to be welded on later.


3. Measured the difference between the original alternator and the GM alternator for the spacers. I used 1/2” inside diameter pipe for the spacers instead of the thin spacers you find in the bins at the hardware store.


I did have to shave the GM spacer (red part) to fit better.


4. To keep the new bracket from rotating I fabricated another brace to attach to the oil filter housing bolt.



5. Welded everything together. I know the brace is a little off but it doesn’t affect the function and it is hidden under the alternator anyway.




6. I wanted an adjustable upper alternator bracket but I could not find any of the linkage style that was short enough so I made my own. It is made with a 3/8” rod end. I wrapped a piece of metal stock around a piece of 3/8” inside diameter pipe, welded it together and drilled a 3/8” hole. The only modification I had to do to the original equipment was the upper alternator bracket. I cut it back to leave about 1” from the timing belt cover. The good thing about this design is that it will also work with the original alternator if I ever decided to go back.



7. Wiring the alternator is very easy. Use the 3 wire GM alternator diagram. The red wire on the plug attaches to the battery post on the alternator. The white wire attaches to the Spider’s battery light wire. It is suggested to upgrade the 10 gauge wire between the alternator and the starter with a 6 gauge wire.

So far I have put about 580 miles on the car with no issues at all. I have brighter lights, faster wipers and it doesn’t bog down when the lights are on and the radiator fan kicks on. Plus, I can get this alternator at any parts store.

I hope this helps anyone who is looking to do the same upgrade. There may be other alternators that are easier to fit. This is just the one I chose.

[spider2081]

Thanks for taking the time to write up the process and results. Sounds great.

[Greg500]

Does anyone know why the pictures are not showing? I am using www.imgbb.com for my photos. Should I use another site? Or maybe I am just misunderstanding the instructions. This is the first forum post
I have ever done so I am not 100% sure how it works.

Thanks

[geospider]

I use Imgur. has worked great, esp after one of the forum members went through the process.
Mult ways to copy and paste: use the BBCode and it works great.
FREE too

[RRoller123]

+1. Imgur is fine, and loads quickly.

Ironically, Photobucket has been sending me emails lately asking if I want to upgrade. Hahahah! Fat chance. They ruined their business model.... see ya.

[Greg500]

I use Imgur. has worked great, esp after one of the forum members went through the process.
Mult ways to copy and paste: use the BBCode and it works great.
FREE too

Thanks geospider. I used imgur and everything is working. I don't know if I more excited about installing the alternator or successfully entering a post on a forum. I'm a hi-tech red-neck now.

[geospider]

I feel you Greg. After getting so much advice, very glad to be on the other end once in a while