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Tired of GM alternators

5K views 17 replies 9 participants last post by  joe_padavano 
#1 · (Edited)
I'm running a 10SI self energizing alternator on my Ford engine. I'm using the 1 wire system. I just replaced the front pulley with a billet one which comes with the nose attachment to cover the mounting nut on the pulley. I also have a idiot light connected that shows charge and a voltage gauge as well. Since replacing the pulley, my light no longer works the way it did. (doesn't come on without a charge) Now I have to rev up the engine to 3K rpm for the alternator to begin charging normally. Does this mean I have to replace the self- ignitor in the alternator, is it going bad? I believe I've replaced it before, or should I just replace the whole alternator with a different model. Any recommendations? 12si? etc. that are more dependable than the older model S10?
 
#3 ·
Is the billet pulley a larger diameter than the original one ? This is normal for these alternators when using oversize pulleys. The alternators turn slower and require a blip of the throttle to reach the self exciting speed. Once it turns on, it stays on. I maintain a couple of road racers that have this setup and a little stab of the throttle turns them on.
 
#4 ·
This may be my problem. The original pulley measured 2 5/8" and the billet is 2 13/16", slightly larger, but may be the reason I have to rev it up higher to ignite the alternator. Once it ignites, it's holding charge at 14.4 volts. While messing with the ampmeter, I triggered something because now the dash lights comes on as before. I'm wondering if there is way of triggering the self ignitor when the ignition key is on without having to rev up the engine? I appreciate the help fellas...
 
#5 ·
If it has the normal terminal connector, it's easy to go two a three wire, then you won't need to blip the throttle etc....

#1 terminal goes to the idiot light.
#2 terminal goes to the hot side of the elec electrical system with a 5 foot, or so, run of wire. The extra wire allows the demand on the elec system to even out, so that the alt gets a nice even demand etc....
 

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#6 ·
I'm running a 10SI self energizing alternator on my Ford engine. I'm using the 1 wire system. I just replaced the front pulley with a billet one which comes with the nose attachment to cover the mounting nut on the pulley. I also have a idiot light connected that shows charge and a voltage gauge as well. Since replacing the pulley, my light no longer works the way it did. (doesn't come on without a charge) Now I have to rev up the engine to 3K rpm for the alternator to begin charging normally. Does this mean I have to replace the self- ignitor in the alternator, is it going bad? I believe I've replaced it before, or should I just replace the whole alternator with a different model. Any recommendations? 12si? etc. that are more dependable than the older model S10?
the pulley you put on different size?? slowing down the alt. rpm?
 
#7 ·
If you want to "fix" your alternator problem read this...
Catalog
I would never recommend a one wire system for all of the reasons stated in the above article.
If you want to learn about wiring whys and hows read through the site. Enough knowledge and tips there to keep you busy fixing the rest of your wiring for a long time.
Mark
 
#8 ·
I wired an SI10 into my 64 and it was pretty easy. It energizes at an idle and is rock solid at 14.64 volts. Much better than the old external regulator system.
If you look at the picture, I still have a regulator but it is dummied out. I tied the 4 wires together -terminals 1 and 4 and terminals 2 and 3, then hooked them at the alternator at the 1 and 2 posistions.I ran a new 10 gauge wire for the 55 amp alternator and tucked it into the convoluted wrap. No muss no fuss.
The Idiot light works as it should also, plus the number 2 terminal (voltage sense circuit as mentioned before) is a long enough run to work correctly.:thumbup:
 

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#10 ·
While we're beating this SI alternator three wire versus one wire to death, remember they have been obsolete for 25 years. There are much better alternators now. Delphi CS130d, CS144, Ford 3G,4G, and Nippondenso alternators all put out about twice the power, have dual cooling fans, much more precision voltage regulators and better reliability. If you are building a car with all the latest things (cooling fans, AC, sound system, and power everything), you need to upgrade to a more modern alternator.
 
#15 ·
You can use a 3 wire 12si as a direct replacement for a 10si, and the stock version is available with output up to 94 amps. If you use all 3 wires it will put out full voltage at just a few hundred RPM above idle. They are also cheap and very easy to find in any auto parts store.

There are newer alternaors (like the CS130) that have higher output, but they are more expensive. Unless you need more than 94 amps, the 12si is a good choice for a V-belt system.

Bruce
 
#16 ·
To answer your wuestion: Yes you can tie it into the pos on the batt, but the sense wire will see a steady 13v from the battery and may not work as well as splicing the #2 wire into the feed just before it goes into the fuse block. No need to cut the feed wirem just strip back the insul about 1 inch, use a screwdriver to pry apart the strands, about 1/2 of the strands on each side of the blade, push the new wire thru the opening in the strands and wrap tightly, apply some solder and put on some liquid elec tape...... nice secure splice.
 
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