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post #1 of (permalink) Old 12-22-1999, 02:18 PM Thread Starter
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Delco Alternator Conversion Or UpGrade Again...

Due to the literally dozens of e-mails I received on this posting, I'm updating it, trying to answer most of the questions, and cover everything at least in a general way...

The one wire alternators just don't live that long (defect in the regulator design). Small case alts. won't live if you throw big loads at them, and so called 'High Output Upgrades' always cause problems.

If you want to convert the GM 10-SI, 12-SI, 15-SI and 116 Type and the like, internally regulated, alternating generators to use on your vehicles, you will need a few things.

1, You will need a 12ga. or 14ga. fusible link or fuse wire.
2, You will need a 12 volt light fixture that has a controlled ground.
(Has two wires, and doesn't ground through the housing or bracket)
3, A GM Style, two wire alternator plug that connects to the side of the alternator.
4, A length of at least 10 Ga. wire (I prefer 8 Ga.) in red insulation.
5, A length of at least 8 Ga. wire (I prefer 6 Ga.) in black insulation.

Connect red wire to the large insulated terminal on the back of the alternator case marked 'BATT'. (8 Ga. recommended)
Connect that wire to the fusible link.
Connect the fusible link to the battery cable side of the starter solenoid.
Your positive battery side hook up is complete.

Run a ground wire (At least one size larger than the charge wire, 6 Ga. recommended) from the ground wire boss on the back of the alternator to battery.
Engine ground, alternator bracket, ect. are unacceptable as substitutes.
Your negative battery side hook up is complete.

Find a wire that is only hot while the Ignition switch is in the 'RUN' position.
(This circuit must be 'off' when the key is turned off.)
Connect to that wire with two leads...
The first, about 16 to 18 Ga. wire, travels through the 'Idiot' light, and then to #'1' terminal on the alternator plug. (Usually a white wire, and smaller than the #2 wire)
The second, about a 14 Ga. wire, travels straight from the switched source to the #'2' terminal on the alternator plug. (Usually a red wire)
Plug in the Alternator, and see if it charges.

If you find an alternator that came out on a vehicle that had air conditioning, and a rear window defrost, you probably have a factory high output unit. Look for the standard size cases though, as there were some odd-balls put out on luxury cars.
If you are going to do deep water fording, or in excessively dusty conditions there are totally sealed units out there. I found about a dozen the other day at the army surplus store for $10 each!

Contrary to what urban myth has to say, an alternator does NOT care which way it turns.

LED style lights will NOT work. It needs to be a regular automotive style bulb. Small dash style bulbs are perfect.
You must have a light socket that controls the ground, as when the alternator is charging, there is 12 volts positive to BOTH sides of the light.
In cases where a light is not wanted, a 100 to 150 Ohm, 1 Watt resistor can be used instead of the light. I like the light idea better...
Almost any automotive parts store will have the parts described above.
Some people substitute a toggle switch for the ignition switch feed, but if you forget to turn off the switch, it will run the battery down, and possibly damage the alternator.

Don't forget to use star washers on all electrical connection, and use a good quality lead plated copper wiring ends. If you are going to be in wet climates, or salted roads, don't forget to solder the ends on, and use heat shrink tubing to make the connections bulletproof. Never trust store bought cables!

If you connect the #1 and/or #2 terminals to the BATT terminal or the battery, like some have suggested, you will have problems. Take your regulator control source (#1 & #2) from inside the vehicle. Your alternator will then compensate for any accessory and parasitic loads that way.

If you don't fuse the system, you stand a very good chance of a fire!
ALWAYS use a fusible link smaller than the charge wire. (Example: If you use a 10 Ga. charge wire, use a 12 or 14 Ga. fuse link. Larger the number, the smaller the wire)
DO NOT attach the fusible link to the battery! If the system grounds and the fusible link burns violently, it can be an ignition source for the battery gasses. Your best bet is the battery cable side of the starter solenoid. This arrangement works on Ford & Mopar engines also.

If you have a GM vehicle, (or a GM conversion) and the battery and alternator both test good, but it still will not charge, Check these three things...
1. Check the idiot light. The system won't charge reliably if the bulb is burned out or missing.
2. Check the fusible link. The fusible link is a soft wire with tape or a plastic collar about 4 or 5 inches from the end.
(Plastic collar is about 1 inch long X 1/2 inch dia.) The fusible link is usually found connected to the battery cable side of the starter solenoid.
3. Check to make sure the alternator is grounded. A good 85% of alternator problems are ground related.

Most factory installed alternators rely on engine ground or alternator bracket ground to service the alternator. BAD IDEA!! Outside of the starter, the alternator will require the largest capacity ground!
Rust on brackets, blocks or in bolt holes, painted surfaces, and loose fasteners all contribute to loosing ground capacity. It doesn't have to be a total break in connection to cause problems or kill the voltage regulator.
The reason the factory didn't dedicate a ground wire to the alternator is $$$. By doing a 'Close Enough' ground, they save the cost of the wire, connection ends, and labor to install it.

So many cats, so few recipes...
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post #2 of (permalink) Old 12-23-1999, 08:41 PM
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Re: Delco Alternator Conversion Or UpGrade Again...

[img]/wwwthreads_images/icons/smile.gif[/img] Superb post Rush guy. I am downloading this to my Jeep Technical manual. I had not even considered that the grounding was a potential for problems, even though I am paranoid about grounding stuff in the Jeep, the alt escaped my notice.[img]/wwwthreads_images/icons/crazy.gif[/img]

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post #3 of (permalink) Old 12-23-1999, 08:53 PM
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Re: Delco Alternator Conversion Or UpGrade Again...

Enough about the alternators where's these recipes?[img]/wwwthreads_images/icons/smile.gif[/img]

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