> Okay. So I go over there to NAPA and ask them for a one-wire GM alternator.
> The good 'ole boy says, "What's it for?"
> I say, "Well, it's an old Triumph and all I need is for it to sorta fit."
> He says, "You can't put this in no motorcycle."
No, he says "Triumph ? Who makes that ?" You say "British Leyland" and he says
"No, I mean who makes it". Third base !
> This next step is where I need help. Assuming that I can get the
> one-wire-model to physically mount-up straight and stout, what do I do then,
> (at a sixth grade learning level), to make it do its thing?
There are different ways to proceed, depending on what you want. For all of
them, you'll need to convert to negative ground (if your car isn't already
negative ground). This involves switching the connections at the battery,
ignition coil, and ammeter.
Then for the minimum alternator hookup, you just remove the two original wires
from the control box, and run a new, heavy gauge (I use 8 AWG) wire from the
alternator output to the battery stud on the starter solenoid. You can leave
the old control box in place as a junction for the brown/white and brown/blue (A
and A1 terminals respectively), or join them together and remove the box.
However, this approach leaves your ammeter always reading discharge (since it
doesn't see any of the alternator output) even when the battery is being
charged.
To get the ammeter to work right, the new wire from the alternator runs over to
where the control box was, and joins with the brown/white and brown/blue wires
that were originally attached to the A and A1 terminals on the control box.
Then you'll need to add a shunt across the back of the ammeter to keep the
alternator from forcing it off-scale. I think I used about 4" of 16 AWG copper
as a shunt last time, worked out OK. You can find the right length by
experiment if you want : note the ammeter reading with the headlight on (engine
off), then adjust the shunt length so you get half of that reading. This will
make the ammeter read 60 amps full scale instead of 30, just about right for
most alternators.
Of course, the IGN warning light won't work ... to get it to work right you need
to start with a conventional 3 wire alternator instead of a 1 wire. Which of
course adds two more wires to run ... but IMO is worth the extra work. The
sense wire goes to the battery stud on the starter solenoid (which improves
charging by compensating for the voltage drop through the wiring & ammeter); the
other wire goes to the yellow wire that used to connect to the D terminal on the
control box and runs into the harness. If you really want to get fancy, you can
add a 10 ohm 5 watt resistor (from Radio Shack) across the IGN warning lamp, but
it's not essential. I like keeping the original gauges and indicators working,
but that's just me (and not on a race car).
HTH
Randall
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