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in the 3 years and 18,000 miles I have had my truck running the alternator has been the most troublesome part of the truck.
I started with a old Ford 1G with external regulator but the regulator failed shortly and it was to small anyway so I upgraded to a 100 amp tuff stuff one wire and it lasted a few thousand miles and then went to putting out 17 volts, I replaced the regulator and same story, few thousand miles 17 volts.
Then I went to a used Ford 2G that lasted a few thousand miles and now I have a rebuilt Ford 3G that I bought on a road trip when the 2G shot craps, ithas been on for 2 years.
I put another regulator in the Tuff Stuff alternator tested it and carry it for a spare.
a note on the Ford 2G and 3G is that they are not 1 wire, they require a wire that is hot with the key on.
Besides being unreliable another thing about the Tuff Stuff that I did not like was they advertise "the most power at idle" and how they do that is put a tiny pulley on to spin it faster, I never could get the belt tight enough to stop it from slipping until I put a larger pulley on it
in the 3 years and 18,000 miles I have had my truck running the alternator has been the most troublesome part of the truck.
I started with a old Ford 1G with external regulator but the regulator failed shortly and it was to small anyway so I upgraded to a 100 amp tuff stuff one wire and it lasted a few thousand miles and then went to putting out 17 volts, I replaced the regulator and same story, few thousand miles 17 volts.
Then I went to a used Ford 2G that lasted a few thousand miles and now I have a rebuilt Ford 3G that I bought on a road trip when the 2G shot craps, ithas been on for 2 years.
I put another regulator in the Tuff Stuff alternator tested it and carry it for a spare.
a note on the Ford 2G and 3G is that they are not 1 wire, they require a wire that is hot with the key on.
Besides being unreliable another thing about the Tuff Stuff that I did not like was they advertise "the most power at idle" and how they do that is put a tiny pulley on to spin it faster, I never could get the belt tight enough to stop it from slipping until I put a larger pulley on it
I was looking at using a Ford alternator and basically found why your describing with quality etc. DELCO 10 SI seems to get better reviews.
Sort of related but I run a GM 10si alternator on my Camaro and have never had an issue or failure in 5k miles. That's not a lot of miles, but still it has been reliable so far.
The truth being that everyone thinks a ONE-WIRE is superior to a THREE-WIRE and GM offers a unit that is cheap to buy but very few understand the application differences.
one thing that I did not like about one wire alternators is that they do not support a warning light.
I got one of these on ebay and it works great. It lights up the light for a bulb test every start up then if the voltage goes below 12 volts or above 15.5 the light comes on.
Has it for over a year
One needs to be very careful with that statement and highly qualify it. There are a dozen or so different wide belt pulley configurations that our flathead V8 trucks could have come with that have different shaft dimensions, and even more that could have been adopted. Then there is the optimization of the outer diameter for alternator RPMs to consider.
I dont trust AI but I will use it as a starting point in my searches. With that said, AI says generators need 600-800 rpm at idle while alternators need 2000-2400 rpm. Stay with the small pulley!
Regarding the statement that the single wire alternator cannot run an idiot light, I believe it can...(going on memory of the research I did when I installed mine). There are 2 electrical blade terminals, under a plastic cap on the 10SI alternator. One terminal is for field excitement. This alternator maintains some residual excitement and doesnt really need the field excitement terminal. But my understanding is that GM used the field excitement terminal to excite the alternator everytime the car is turned on. This will help in the case if the car sits long periods and the residual excitement is lost.. which was my case when my truck sat for 3+months!. I had to jump the terminal to excite it and get it charging again.
The other terminal is for the idiot light.
It makes me wonder if GM ever really used it as a true one wire? It was my belief they always used the 2 blade connectors to keep it excited and to have the idiot light.
I dont trust AI but I will use it as a starting point in my searches. With that said, AI says generators need 600-800 rpm at idle while alternators need 2000-2400 rpm. Stay with the small pulley!
Regarding the statement that the single wire alternator cannot run an idiot light, I believe it can...(going on memory of the research I did when I installed mine). There are 2 electrical blade terminals, under a plastic cap on the 10SI alternator. One terminal is for field excitement. This alternator maintains some residual excitement and doesnt really need the field excitement terminal. But my understanding is that GM used the field excitement terminal to excite the alternator everytime the car is turned on. This will help in the case if the car sits long periods and the residual excitement is lost.. which was my case when my truck sat for 3+months!. I had to jump the terminal to excite it and get it charging again.
The other terminal is for the idiot light.
It makes me wonder if GM ever really used it as a true one wire? It was my belief they always used the 2 blade connectors to keep it excited and to have the idiot light.
the problem that I had with the small pulley was I could not get the belt tight enough to stop the belt from squealing. I went back to the standard 1G larger alternator pulley and it stopped the squealing. always 14 volt at idle
I too have the understanding that GM never used a true one wire alternator in any automotive application, but some later models could self excite at higher RPMs. There are so many aftermarket takes on the 10SI that have different internals that you can't say a 10SI is a 10SI is a 10SI. Some expose the two terminals highlighted above, some don't. Those that do expose the terminals don't necessarily have them internally connected and configured "to spec". "Ignorance is bliss" when one only looks at volts and not the system as a whole.
How a authentic 10-SI is internally configured (straight from AC Delco):
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