> I would like some help on figuring out if the GM alt is wired
> correctly on
> my 72 TR6. While getting her started for the first time in 14
> years and after
> about 2 minutes of running, I let some smoke out of the alt and
> the amp gauge.
> The only part of the harness that looks bodged is the hookup on
> the alt. This
> is how is wired now: the big brown and white wire is on the B+
> post with a
> jumper to the F plug in, the R plug in is hooked to the brown and
> yellow wire.
> There is one brown and yellow and one brown (maybe brown and
> green) in the
> original plug that have nothing hooked to them.
> Does this sound right? Or do I need to look for something else
> that caused my smoke test.
Bill, what model of GM alternator do you have ? I'm not certain how all of
them are marked, but 10Si and 15Si internally regulated GM alternators have
the side terminals marked 1 and 2. F and R were only on externally
regulated models, as I recall.
However, again depending on exact model, the GM alternator is probably
putting out a lot more current (when the battery is discharged, like right
after starting the engine) than the old Lucas. That means all the charging
wiring has to be top notch or it will get hot. Any iffy connection might
well let the smoke out. I'm not familiar with the wiring on a 72 TR6, but
since IMO the original alternator connection was inadequate, it might well
be that the connections to the ammeter are too. Those big 'Lucar' terminals
are good for maybe 30 amps continuous, but 45 is too much and 60 (as you're
probably getting now) is way too much. You might try adding a second large
wire (10 or 12 AWG) from the alternator output to the battery terminal on
the starter solenoid. This will bypass some of the charging current around
the original charging wiring, but hopefully allow everything to work
normally. The reading on the ammeter will be reduced considerably, but
that's likely a good thing too.
Next step of course is to hook up a voltmeter and be sure your new
alternator isn't trying to overcharge the battery.