Alternator wiring
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Alternator wiring
I am starting an engine swap that I have been told is pretty straight forward. I have a 1986 Auto F250 4X4 with a bad 302. I have purchased a complete 1990 351W out of an E350 Van with computer, flywheel and all of the accessories. I have encountered my first dilemna. The 351 alternator only needs two wires. The old 302 alternator appears to have an external regulator and numerous wires. My preference is to use the newer 2 wire alternator. Is this possible and could someone tell me how to wire it?
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I will have to take a closer look at the 1990 alternator to see if it is wired like the diagram you sent. I only saw a total of three wires. The heavy red wire from the battery and a two wire plug. If the red wire splits into three wires inside the alternator and the other two wires in the diagram are the ones on the plug then this is the right wiring diagram. It will take me a day or so to check it out. Do you have a diagram for the origional 1986 F250 alternator? Thank you for your help.
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From: Miami
I have a schematic for both alternators, if you have access to a fax machine, I will fax them to ya. Or if ya can wait I will be doing the wiring on my Bronco this week and have the same situation you have. I have a scanner but don't know how to use the damn thing!!!! You will have to buy a external voltage regulator. The alt. you are installing is a 100 amp. You can go to a auto store and ask for a regulator for a 250 or 350 van.
Al
Al
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From: Virginia
Here's a diagram of the old external reg system.
One thing I have to ask, did the newer truck have an idiot light? You will notice the 1990 diagram has an idiot light in the dash. If the older truck had an ammeter instead of the idiot light, then it's going to be a pain to add the idiot light, unless you can find a diagram to wire the newer alt without an idiot light.
Can you use the older alt on the newer engine? As you can see, it's pretty simple to hook up.
One thing I have to ask, did the newer truck have an idiot light? You will notice the 1990 diagram has an idiot light in the dash. If the older truck had an ammeter instead of the idiot light, then it's going to be a pain to add the idiot light, unless you can find a diagram to wire the newer alt without an idiot light.
Can you use the older alt on the newer engine? As you can see, it's pretty simple to hook up.
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I have a similar problem w/ a 87-351W-F250-4X4. I'd like to simplify the wiring. Is there a reliable one-wire or even a three-wire replacement for 351W? I've seen articles about converting a GM case to Ford use, any opinions? thanks, John.
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From: Virginia
I am sure you can do a google or yahoo search and find a one-wire alternator that will fit a Ford. I never used a one-wire because I want to run down to the store and get a replacement if the factory style one gives out. If you don't mind ordering a one-wire if it goes out, then by all means buy one. I would probably have to consider one if I had a show vehicle and wanted to clean up the engine compartment. Otherwise, the factory external regulator system works pretty well, even though it has a few more wires.