John,
I've written up about using the one wire alternators in the past.
I know there are at least EIGHT people who have done the installation,
and was hoping they would pass along the information.
QUICK REVIEW:
How large is the alternator? How many amps?
The OEM wiring harness was designed for only a 35 amp alternator,
and any dirty (corroded, poor splice, mechanically no sound) will
have a resistance to it. This resistance will drop voltage and
produce heat! While 10 Amps passing through a 0.1 Ohm resister
doesn't sound like much, but it will be a 1V drop (Amps * Resistance).
This is also a 10 Watt of heating (Amps^2 * resistance).
Now take that same resistance drop and increase the current to
something like 40 amps of current. That would be a 4V drop
(very noticeable) and something like 160 Watt. Try grabbing a 100
Watt light bulb to get an idea. This will cause a wiring harness
fire.
I'd just run the "+" terminal of the alternator straight to the battery.
Also run a good size ground cable to the "-" side of the battery,
connecting to the alternator ground.
Add a second wire, with a fusible link, between the "+" stud on the
alternator and the original wire.
I also recommend adding an additional fusible link inline with the
power wire coming off the starter. There are three wires (not
the battery cable) in the small harness to the starter. One is for
the starter solenoid, the other two for power leads. One power lead
will hook up the ammeter, the other is for non-ammeter loads (like
the horn).
Obviously not all the current will pass through the ammeter, only
aportion of it. Your ammeter will still have some reading of current,
but not all. Should the lead from the alternator to the battery "+"
connection be disconnected, you have the fusible links to prevent
damage to the wiring harness.
Summary:
1. Keep to a 60Amp alternator (Maximum).
2. Additional wire (12 guage, fine stranded) from the alternator "+"
stud to the battery "+" terminal.
3. Additional wire (12 gauge, fine stranded) from the alternator chassis
to the battery "-" terminal.
4. Add a fusible link (14 guage wire) to the original wiring harness
connector, then connect to the "+" stud on the alternator.
5. Add a fusible link (14 guage wire) to the original power lead that
comes off the starter stud.
I like using MOLEX heat shrinkable - sealing connectors. Napa charges
something like $6 for 5 of them. Cheap insurance in the long run.
REMOVE the battery from the car anytime you are working on the electrical.
Not sure where I stored that original write up, but this should cover it.
A friend ignored the advice on fusible links. Claimed he dropped in a
60 Amp Alternator, and no problem. Stock wiring and everything worked
just fine. You guessed it, five years later he was looking for a new
wiring harness. Seems his got a little toasted!
Cheers,
Tom Walter '67 2000
Austin, TX '68 2000
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