Quick Notes
What We Did
Replaced the old and worn-out alternator with a 130-amp DUI unit
Bottom Line
Keep the jumper cables at home.
In the name of wiring and...
In the name of wiring and electronics safety, we disconnected the negative battery terminal. Then we used a 7/16-inch wrench to disconnect the factory wiring from the threaded post from behind the factory alternator.
While most DIY-ers out there don't necessarily have a car full of expensive electronic devices to run, we do, however, still need a properly charged battery for cold-cranking in the winter months. And if you've got a slew of interior instruments to run and upgraded headlights, LED taillights, EFI, or an underdrive pulley, then the factory-style alternator may be straining to recharge the battery while driving. If you find yourself continually charging your battery only to find it weakened time after time, the alternator may be to blame.
In a nutshell, an alternator is the car's own charging system and is spun by the engine's drivebelt. The alternator converts mechanical energy from the engine's drivebelt into electrical energy. Once the engine is running and rpms rise during driving, the alternator spins, recharging the battery. But smaller-diameter pulleys don't have the ability to spin the alternator at the rate necessary to recharge the battery. Also, things like heat generated from an overworking alternator may also contribute to a weakened charge for the battery.
While our project '72 Nova only had an aftermarket head unit and four relatively small speakers, we did have a three-gauge pod and a G-Tech unit to power. We also have plans in the works to install more accessories, including an electric fuel pump, which could potentially strain our aging factory-style alternator. We needed an upgrade. DUI offered up a Mr. Amp (130-amp) alternator as a solution, but also offers a 190-amp version. They'll maintain peak performance in the ignition system and even produce 65 amps at idle, which help eliminate battery drain on underdriven pulley applications.
Fortunately, replacing an alternator is a cinch. Using only handtools, we removed and replaced the old alternator with a more efficient Mr. Amp alternator. We go step by step to give you the rundown on how to do one yourself.
With those connections removed,...
With those connections removed, we could loosen up the bolt that fastens the alternator to its bracket. We used a 1/2-wrench. Once the bolt was removed, we could spin the alternator housing clockwise and also remove the V-belt.
The bolt that fastens the...
The bolt that fastens the alternator onto the cylinder head was removed last and required a 9/16-inch wrench. It was then that we could yank the old alternator out of the engine bay.
The bolt that fastens the...
The bolt that fastens the alternator onto the cylinder head was removed last and required a 9/16-inch wrench. It was then that we could yank the old alternator out of the engine bay.
Since the stock alternator...
Since the stock alternator utilizes a smaller mounting hole than the Mr. Amp alternator, we used the sleeving kit (provided) so that we could still use the stock mounting bolt. We installed that bolt through the alternator and threaded it into the cylinder head. We locked it down snuggly with a 9/16-inch wrench.
Next, we located a position...
Next, we located a position on the firewall for the thermal circuit breaker and fastened it down using some machine screws. Then we cut the 6-gauge wire to length. We ran enough cable from the battery to the thermal circuit breaker and then from the circuit breaker to the back of the alternator. Crush-type terminals are provided and we put those on each end of the bare wire as well.
Starting from the battery,...
Starting from the battery, we ran the 6-gauge wire through the passenger-side fender and toward the firewall. There we connected the terminal to the thermal circuit breaker using a 1/2-inch wrench. We followed the same steps to attach the other end of the wire from the thermal circuit breaker to the back of the alternator.
Our Mr. Amp comes with a new...
Our Mr. Amp comes with a new three-wire plug. We followed these simple steps to wire up our Mr. Amp.
a. Yellow wire with White stripe: connects to the positive post on the back of the alternator. We looped this wire over to the threaded post where we attached our main positive battery cable.
b. White wire with Black stripe: Connects to the single solid White wire pigtail that we plugged into the alternator.
c. Green wire with Red stripe: Connects to a 12-volt ignition source that is "hot" only when the key switch is on. Note: If you have an idiot light on the vehicle, this wire must be connected to it for the light to function.
Using the three-wire plug,...
Using the three-wire plug, we attached it to the back of the alternator. In our case, the plug was simple to reach however it may be wise to attach this plug before the alternator is installed into the engine bay.
With the wiring complete,...
With the wiring complete, we double-checked our work, making sure all the connections were solid and tight. Then we attached the 6-gauge wire to the battery terminal.