picture courtesy of Jeff Korn
INSTALLING A 130 AMP 3G ALTERNATOR IN YOUR TURBO COUPE
All
Turbo Coupes came
with either a 65 Amp
of 75 Amp alternator
from the factory.
While
somewhat adequate
for 83 to 86 model
years that have one
engine cooling fan,
and no other added
electrical
accessories, such as
a high powered
stereo, these low
power alternators ,
in my opinion, do
not put out enough
power for 87-88 cars
that have higher
electrical demand
due to their two
engine cooling fans,
programmed ride
control, and
antilock brakes.
I have heard
of high failure
rates of stock
alternators in 87 -
88 cars, and I
believe this is due
to the high power
demand placed on the
alternator, forcing
it to run at a large
fraction of its
rated output much of
the time, which will
shorten its life. A
solution to this
problem is to
upgrade to a Ford 3G
(third generation)
130 Amp alternator,
which will provide
more than enough
power to handle any
electrical load.
This upgrade
is very common in
the 5.0 Mustang
world, and while
installation on a
Turbo Coupe is
slightly more
involved, it is
still pretty much of
a straight forward
swap. I did this
swap several years
ago on my 86
Thunderbird 5.0, and
have been very
pleased with the
results, so I bolted
one up to my 88
Turbo Coupe to enjoy
the same freedom
from inadequate
charging power.
picture courtesy of
Jeff Korn
PARTS
AND TOOLS NEEDED:
A 130 Amp 3G alternator. These are available from many sources. I got a new one from PA Performance (www.pa-performance.com). I purchased their alternator upgrade kit for 87 to 93 Mustangs for $189, which includes a new stator plug, and upper mounting bolt. These alternators can be found at the local parts store for about $200 (ask for an alternator for a 94 Cobra), or the junk yard. My personal feeling with parts such as alternators is to pay the money for a new part, versus getting one from the junk yard for $50 that already has had 100,000 miles of use. The PA performance alternator comes with a threaded upper mounting hole and a bolt.
The
3G alternators from
the parts store or
the junk yard do not
have a threaded
upper mounting hole,
so if you get one of
these, you will need
a 1/4" bolt
about 3 inches long,
and a nut. If you go
the junk yard route,
be aware that not
all 3G alternators,
which can be
recognized by their
dual internal fan
design, Aswiss
cheese@ front cover
plate, and stud
terminal output, are
not all rated at 130
Amp output.
Some are
rated at 90 or 95
amps, and may be as
low as 75 Amp.
The
alternator in my 91
Escort has the
typical 3G design,
but has a smaller
case, and is only
rated at 75 Amps.
All 130 Amp versions
I have seen say “130
Amp” on a stick on
tag located on the
case, and the
voltage regulator
says “heavy duty”.
A
stator plug,
which is a small
single terminal plug
unique to the 3G
series of
alternators. This is
included in the PA
Performance upgrade
kit, or can be
obtained from Ford
for a few dollars,
or free from the
junk yard (grab one
and put it in your
pocket).
If you
have an 83 –86
with an externally
regulated
alternator, you will
also need a new
voltage regulator
three terminal “D”
shaped plug. They
are available from
PA performance,
Ford, or the junk
yard.
My regulator
plug was in pretty
sad shape, so I
replaced it with a
new one.
About
6 feet of 10 gauge
wire and four 10
gauge compatible
ring terminals.
Some
kind of grinder to
modify the lower
alternator mounting
bracket.
A
soldering gun and
electrical solder.
A pencil type
soldering iron will
not work. A
soldering gun rated
at least 140 Watts
is needed to solder
the heavy gauge
wires involved.
Half way
decent soldering
skills are also a
requirement.
Typical
hand tools /
supplies-
wrenches, sockets,
electrical tape,
wire cutters and
strippers, single
edge razor blades,
etc.
A voltmeter to check your work.
THE SWAP
Disconnect
the positive battery
terminal.
(Personally,
I never do this, but
then I have 30+
years dealing with
electronics, and
feel safe leaving
the battery
connected, but I
urge most to
disconnect it.)
Remove the
alternator drive
belt. Undo all the
electrical
connections to the
alternator and
voltage regulator.
This depends
somewhat on what
year your car is.
For 87-88,
remove the regulator
plug and heavy gauge
power output lead
from the stud on the
back of the
alternator.
For 83-86
externally regulated
cars, remove the
wiring from both the
regulator and
alternator. The
external regulator
will not be reused.
Unbolt the alternator upper and lower mounting bolts, and remove the alternator. On my 88, the lower mounting bolt wouldn’t come out all the way without hitting the coolant overflow tank, but it came out far enough to get the alternator out.
Now is a good time to compare the pulley diameters on both the old and new alternators. If they are much different, reuse the original pulley. The pulley on my new 3G was virtually the same diameter as the original.
The 3G alternator has a larger case than the OEM alternator, so some trimming of the lower alternator / power steering bracket is necessary. Refer to the “ before and after” figures to get a feel how much material must be removed from the bracket.
above
pictures courtesy of
"Joe
Frazier" at JoeCool@RustecAT.com
, from http://www.rustecat.com/images/3g/
I covered the rest of the engine with an old sheet so as not to get metal filings all over everything while grinding. The Areconfigured@ bracket looks like a real hatchet job, but this area will be fully hidden by the new alternator. This bracket is quite massive, so I do not think the amount of metal removed will compromise its strength. To determine exactly how much to trim from the bracket, I put the new 3G alternator in using the lower mounting bolt, and use a strip of paper between the alternator case and bracket to see where material needed to be removed from the bracket. I continued to remove material from the bracket until the upper mounting holes lined up. It took me about 20 minutes with the air powered cut off wheel / grinder shown in the figure to trim the bracket.
picture courtesy of
Jeff Korn
IN
WITH THE NEW
Once
the bracket trimming
is complete, install
the new alternator
using the original
lower mounting bolt,
and either a new nut
and bolt, or just
the new bolt
included in the PA
Performance upgrade
kit to attach the
alternator to the
upper mounting
bracket.
Note that the
regulator input and
stator input point
straight down.
You can still
get the plugs on,
and it actually
leads to a cleaner
look with them
pointing down.
It is not
recommended that you
try to “reclock”
the alternator to
reposition the
terminals.
Now for the electrical wiring. This will depend on which alternator you just removed – internally or externally regulated. The only difference between the two is wiring the regulator. The power output wiring is the same for both.
Internally
regulated (87-88). Look
at the regulator
socket on the 3G
alternator. The
terminals will be
marked I, A,
and S.
Now, look at
the three terminal
regulator plug.
There will be a
light green /red
wire, a yellow /
white wire, and a
black /white or all
black wire. As
far as I know, these
color codes remained
constant over the
years.
Temporarily
reconnect the
battery, and measure
the voltage on the
yellow / white wire,
which should be 12
V. This is the
voltage sense wire,
and needs to be
connected to the A
terminal on the
regulator (through
the regulator plug,
of course).
The light
green / red wire
should have 12 Volts
present when the key
is in the run
position only.
The voltage
on this wire tells
the regulator the
car is running, and
needs to be
connected to the I
terminal on the
regulator.
The black
or black /
white wire needs to
be connected to the S
terminal on the
regulator, and to
the stator
terminal next to
the regulator
connector using the
stator plug you
obtained earlier.
Figure four
shows the wiring for
the 3G alternator.
Disconnect
the battery again
after you have
confirmed the
voltages on these
wires.
Be sure to
solder and tape up
all connections!
Note that on
my 88, the regulator
plug had all these
wires, but in the
incorrect order,
which required some
cutting and
splicing. Also,
on my 88, the black
wire just went into
the harness, and
ended – it was not
connected to
anything.
Externally regulated (83-86). Be sure you have a three terminal D shaped regulator plug before you begin. Look at the regulator socket on the 3G alternator. The terminals will be marked I, A, and S. Now, look at the wires going to your external regulator. There will be a light green /red wire, a yellow / white wire, and a orange/light blue wire. As far as I know, these color codes remained constant over the years. Temporarily reconnect the battery, and measure the voltage on the yellow / white wire, which should be 12 V. This is the voltage sense wire, and needs to be connected to the A terminal on the 3G internal regulator (through the regulator plug, of course). The light green / red wire should have 12 Volts present when the key is in the run position only. The voltage on this wire tells the regulator the car is running, and needs to be connected to the I terminal on the 3G internal regulator. Disconnect the battery again after you have confirmed the voltages on these wires. The black or black / white wire which is connected to the S terminal on the regulator via the regulator plug, needs to be connected to the stator terminal next to the regulator connector using the stator plug you obtained earlier. The orange/light blue wire between the external regulator and the original alternator is not used. Figure four shows the wiring for the 3G alternator. Be sure to solder and tape up all connections! The original external voltage regulator can be removed.
Connecting the alternator output. On a 5.0, this is easy… just run a 4 or 6 gauge wire from the output stud on the alternator to the battery terminal on the starter solenoid. Unfortunately, due to wiring differences between our cars and 5.0s, which is mainly due to the amp gauge on our cars, this is a somewhat more involved process. I am sure there are other ways to do this, but using my method does not overload any of the smaller power feed wires, and pretty much preserves the operation of the amp gauge.
Cut two sections of 10 gauge wire about a foot long, and a third section about two feet long. Put ring terminals on one end of each, and secure to the alternator output stud. Do not over tighten this connection. Put another ring terminal on the other end of the longer 10 gauge wire, and attach this wire to the battery stud on the starter solenoid. Be sure to solder, as well as crimp the wires to the ring terminals.
Now
comes the fun part. Locate
the huge taped
bundle of wires mid
way between the
alternator and the
starter solenoid.
This is the
main wiring
junction. The
original output wire
from the original
alternator goes into
this bundle.
Use a knife,
razor blade, etc. to
cut the tape off the
bundle. Inside you
will find a thick
yellow wire with a
huge splice into
several fuse links
at each end.
The yellow
wire is the shunt
wire for the amp
gauge.
Follow the
original alternator
power output wire to
the splice at one
end of the yellow
wire.
Cut the
original power wire
a few inches from
the huge splice, and
connect it to one of
the two remaining 10
gauge wires from the
alternator.
Be sure to
fully solder and
tape this
connection.
Use a knife
or razor blade to
remove about ¾”
length of insulation
from the thick
yellow wire near the
same end that the
alternator power
wire is spliced in
to.
Strip some
insulation from the
last 10 gauge wire
coming from the
alternator, wind it
around the bare
section of the
yellow wire, solder
completely, and tape
the connection up.
Push the
wires all back
together, and retape
the whole bundle up
so it looks more or
less like it did. A
tie wrap around the
whole mess of wires
will help hold them
together before you
tape them up.
Next, tape
wrap the bundle of
three 10 gauge wires
with a good layer of
tape, and enclose in
split loom to
eliminate any
possibility of the
wires chaffing. Note
this is shown in
figure five also.
Plug the
regulator and stator
plugs into the new
alternator from the
bottom.
Last,
securely reconnect
the positive battery
cable. You are done!
Note that
if you try to skimp,
and just run ONLY
the original power
wire only to the new
alternator, you WILL
overheat the wire,
and possibly start a
fire due to the high
current output of
the alternator!
Attach
a voltmeter across
the battery.
It should read
around 12.5 V or so.
Start the car.
The voltage
should quickly
increase to 13.9 to
14.4 V, depending on
the regulators
temperature.
In cold
conditions, the
regulator increases
charging voltage.
Turn on the
headlights and
heater blower to
high. Battery
voltage should only
drop a few tenths of
a volt, if at
all.
Now you can add just about any electrical accessory to your car you want without fear of overtaxing the alternator. No longer will your lights dim at idle, and as a side benefit, you can expect longer alternator and battery life.
View of the complete installation:
picture courtesy of
Jeff Korn
.