DELCO SI SERIES ALTERNATOR INFORMATION & UPGRADE
With FAQ Section



QUESTON?
Why Not Just Use One Of The Aftermarket 'Mega-Amp' or 'One Wire' Alternators Out There??

ANSWER:
The one wire alternators just don't live that long (defect in the regulator design).
If one wire were such a good idea, don't you think the factories would be doing it all the time?
The answer is you can't make a one wire alternator live through a new car warranty and you can not make it regulate the voltage well enough for modern electronics.

Huge amprage small case alts. won't live if you throw big loads at them, and so called 'High Output Upgrades' always cause problems. Over building an alternator may seem like a good idea, but there is only so much capicaty for cooling the rectifier.
When overheated, there is no warning, the diodes in the rectifier just fail for good.



QUESTION?
What If I Have A Delco Alternator Now, But I Need A Larger Amperage Output?

ANSWER
Just Switch To One Of The Factory High Output Alternators.
They are the same same plug configurating, and wiring configuration, and in most cases same case size, same bolt pattern, and same pulley type.
A little leg work at the auto parts store should yield satisfactory resulsts.
You are looking for an alternator from a GM product, usually a large luxery car, with power everything!


QUESTON?
What if I have an EXTERNALLY REGULATED Prestolite, Ford, Chrysler, or whatever type alternator, and I want to convert to Delco Internally Regulated Alternator?

ANSWER:
If you want to convert the GM 10-SI, 12-SI, 15-SI, 17-SI and 116 Type (and the like), internally regulated, alternating generators to use on your vehicles, you will need a few things.


AND HERE IS YOUR SHOPING LIST:

  1. You will need a 10 Ga. or 12 Ga. fusible link or fuse wire.
    (10 Ga. Fuse if you use 8 Ga. Wire// 12 Ga. Fuse if you use 10 Ga. Wire)

  2. If you want a charging system warning light (Idiot Light),
    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. If you don't want to run a warning light, you will need a Diode, (Radio Shack P/N ????)

  4. A GM Style, two wire alternator plug that connects to the side of the alternator.

  5. A 15' length of 18 Ga. wire with White insulation.

  6. A 15' Length of 16 Ga. wire with Red insulation.

  7. Heat shrink tubing for insulation. Red & White if possable.
    (Radio Shack P/N )

  8. An 8' length of at least 10 Ga. wire (I prefer 8 Ga.) in Red insulation.

  9. An 8' length of at least 10 Ga. wire (I prefer 8 Ga.) in Black insulation.

  10. Round connector 'Eyes' for 10 Ga. wire (I prefer 8 Ga.), all copper or copper with silver cadmieum plating.

  11. Silver bearing, Rosin Core Solider.
    (Radio Shack makes a good silver content solider, P/N )



    How To Wire Your Upgrade From Scratch...


    Click Here For Wiring Diagram With 'Idiot' Light.

    Click Here For Diagram Without 'Idiot' Light



    1. 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.


    2. Run a ground wire (8 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.


      With 'Idiot' Light

    3. 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 one lead.
      Terminal #1 on the alternator plug uses about 18 Ga. wire with White insulation, travels through the 'Idiot' light, and then to #'1' terminal on the alternator plug.
      (Usually a white wire, and smaller than the #2 wire)

    4. The second wire, about a 16 Ga. wire with Red insulation, travels straight from the the #'2' terminal on the alternator plug to the 'Hot' side of the horn relay. (Usually a red wire)

      The reasons for using the Horn Relay...
      The Horn Relay is at the end of the wiring harness, and will have some of the lowest voltage in the system so the alternator knows to add more voltage,
      The horn relay is already fused, so you don't have to add another fuse,
      The horn relay is wired with a large enough wire to support the current draw of the alternator regulator.


      Without 'Idiot' Light

    5. Find a wire that is only hot while the Ignition switch is in the 'RUN' position.
      Terminal #1 on the alternator plug uses about 18 Ga. wire with White insulation, travels through the diode and then to #'1' terminal on the alternator plug.

      ('Arrowhead' on the diode pointing at the alternator),

      Connect to that terminal with the 18 Ga. wire with White insulation to your switched source.
      (Like the positive side of the ignition coil. That circuit is only used when the key switch is in the 'RUN' position, and it's very handy in the engine bay.)

    6. The second wire, about a 16 Ga. wire with Red insulation, travels straight from the the #'2' terminal on the alternator plug to the 'Hot' side of the horn relay. (Usually a red wire)

      The reasons for using the Horn Relay...
      The Horn Relay is at the end of the wiring harness, and will have some of the lowest voltage in the system so the alternator knows to add more voltage,
      The horn relay is already fused, so you don't have to add another fuse,
      The horn relay is wired with a large enough wire to support the current draw of the alternator regulator.

    You are now done with the install, connect the battery, start the vehicle and see if your install works.



    WARININGS!!!


    If you connect the #1 and/or #2 terminals to the BATT terminal or the battery you will have problems.
    Take your regulator control source (Terminal #2) from after the fuse block.
    Your alternator will then compensate for any accessory and parasitic loads that way.

    DO NOT EXCLUDE THE FUSIBLE LINK!

    If you don't fuse the system in the manner described above, 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 GM, Ford, Mopar & AMC engines.



    NOTES:

    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, The Delco SI Series alternators do NOT care which way it rotates.

    I like the warning light idea better...
    ('Idiot' light).
    LED style lights will NOT work as 'Idiot' lights.
    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 diode, or 100 to 150 Ohm, 1 Watt resistor can be used instead of the light.
    (I prefer the diode to a resistor, more reliable and easier to do.)

    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 or zinc cadimum 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!



    TROUBLE SHOOTING:

    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.
    If you opted not to have a light, or your vehicle didn't come with one, check the resistor or diode just behind the alternator 2 wire plug.

    2. Check the fusible link. The fusible link is a soft wire with tape or a plastic collar about 3 or 4 inches from the end.
    (Plastic collar is about 3/4" 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.