The Alternator
is a far superior generating machine than its predecessor the Generator.
Moreover, the semiconductors that made it possible also enable the charge
regulator that comes with an Alternator to be much more efficient than the
electro-mechnical type that was used with Generators. These instructions
discuss conversion to the 3 terminal Alternator, the only type now readily
available new or refurbished.
Make sure you read all the instructions below, so that the right parts are
procured ahead of time and the magnitude of the task is understood.
Preparation
1.
Make sure you already have a Negative ground car.
If the electrical system is still Positive ground, then procedures 1, 2, 4, 5,
6, 7, and 8 of Conversion
- Positive to Negative Ground, will need to be completed first.
2. Prepare the mechanical hardware.
The
length of the Alternator is somewhat shorter than the Generator it is
replacing. The brackets on the engine accommodate the span for the Generator,
shown by the red arrow, of 6-3/32" (154.8 mm), whereas that for the
alternator is only 3-7/8" (98.4 mm) or 3-5/8" (92 mm), depending on
type. The difference is best taken up by making a steel spacer tube equal
to the difference in length.
The tube shown here has
been cut from stock steel pipe and covered in heat shrink tubing for aesthetic purposes.
Cut as squarely as possible and to a shorter length rather than longer, then
use washers to shim up the difference. It is important to get the spacer right
because the flanges on the Alternator must not be put under strain.
A 1/4" X 3-3/4" (M7 X 90 mm) bolt will be needed to span the
spacer with 2 appropriate flat washers and a single shake proof. It is worth
getting new fasteners for the other end too, 1/4" X 2" (M7 X 50 mm).
Procedure
3.
Disconnect the Battery (ies).
4. Remove the Generator and install the
Alternator in its place using the hardware discussed above. Obtain the right fan belt for the
Alternator and fit that in place of that used with the Generator. The
Alternator pulley is smaller, requiring a shorter belt. Even if the old belt
appears to fit it will have bedded into the old Generator pulley and should not
be used on the new one.
5. Remove the Ground connection from the E terminal of the
Regulator. Tape it back so there is no danger of it touching any live
connections.
6. Reterminate the
regulator,
which will not be used but which provides a good anchor point for the
wiring. Note that the illustration shows the newer regulator with push-on
terminals, earlier Regulators had screw terminals.
Remove the
thick Brown/Yellow wire from the D terminal (don't
confuse this Brown/Yellow wire with the thinner one that goes to the WL
Terminal) and connect it to the B terminal together with the Brown
wire(s), and sometimes a Green wire, already there. This is easy to do
with screw terminals but piggyback connectors may be required for Regulators
with push-on terminals. .
A selection of such
devices is shown at left. Use whatever type you can obtain but do NOT
put the feed from the Battery on one of these. It is the heaviest wire and
always live, so reserve one of the B terminals for that wire. If you are
unsure which is the battery feed, temporarily reconnect the battery and use a Circuit Tester to check which of the Brown
wires is live.
Now remove the Brown/Green wire form the F terminal and move it
to the D terminal. Again, screw terminals make the job very easy. With
push-on connectors, cut off the contact and crimp on a larger size to fit the D
terminal.
7. Connect the Alternator.
The existing connectors that were used on the Generator should work fine
with the Alternator.
The photo at left shows the approximate
position of the Alternator contacts when installed on the engine. Attach the
small contact with the Brown/Green wire to the small terminal arrowed F
(field). Then connect the heavy Brown/Yellow wire with the large
connector to either of the wide contacts arrowed + (positive).
8 Reconnect
the Battery (ies) and test the system.
Make sure
everything is switched OFF. As the battery is reconnected, check there are no
sparks that would indicate that something (that shouldn't) is drawing a high
current.
Switch the ignition ON. Check that the Ignition Warning Light illuminates.
Start the car and check the Ignition Warning Light extinguishes.
If you have a voltmeter, check the voltage at a Brown wire at the Fuse
Block. It should reach over 13.5 volts when the engine is revved hard.
By Rick Astley