Installing The Single Wire 12 Volt Alternator

This article pertains to the installation of the 12 volt, single wire alternator. The alternator is a General Motors style that only requires that you connect the existing wire previously used on your old generator, once the new single wire alternator has been installed. The voltage regulator is internal and set.

First and most importantly, remove the positive cable from your battery before any alternator or generator repairs are made. In this case, you will of course remove your old 6 volt battery entirely. I placed my new 12V battery on a charger to assure it was fully charged before installation. This is important so that the new alternator will not overheat trying to charge a new battery that may have been on the shelf for a while and has lost some of its charge.

There are three bolts, all of which are attached from the front of the engine near the oil fill port. One of these bolts secures the timer bracket if you still use that type of ignition system, either with coil boxes or the True-Fire. Support the generator with your left hand while removing the last bolt, which it helps if you save the top bolt to be removed last. This keeps the generator from resting on the lower bolts and binding them up during removal. Removing the oil filler cap allows you to see the generator gear as it sets in the timing gear of the camshaft and crank gear with a shop light. This helps while installing the new alternator. I used the front hand crank to align the gears of the new alternator. It went right in. Then I put some engine assembly lube on the gears through the oil filler cap. This may not be necessary, but it made me feel better knowing the alternator gears were not dry when I first cranked the car after installation.

I purchased my new alternator from Texas T Parts, part number T5119ALT-12. In the instructions, Ben stressed, "Do not get into a test of strength while tightening the new alternator." They do go in slowly and they feel as though they are cross threading. I backed off the installation of the new alternator and placed it on the bench. With the gear and mounting holes facing down, I used the proper tap and cleaned the paint out of the holes of the new alternator. I then made sure the bolts were cleaned and the bolts went into the new alternator a bit easier. You still need to exercise some caution installing the bolts.

The electrical eyelet on the existing generator/alt output wire on our T was too small for the output stud on the new alternator. I replaced it with the proper size eyelet. However, I did not want a modern looking "blue" eyelet insulator showing under the hood. So, before you install the new eyelet get a 1 1/2 inch piece of black shrink tube (heat shrink) and place it on the wire. Crimp the new eyelet in place, then put the shrink tube over the blue insulator and heat the shrink tube until it has properly sealed over the blue insulator. Wah lah! You can't tell a new insulator has been installed. Attach the output wire to the new alternator, then get to the battery.

My new battery would not fit in the battery box at all with the integrated battery carrier strap. I used a hack-saw to carefully remove the strap. I then used a battery carrier that utilized the posts to lower the battery down into the battery bracket in the car. I had two pieces of heater hose ready to place over the battery positive battery post to keep it from accidentally touching any metal part of the battery box. I left it on until the battery was securely in place and ready to install the cable. Be careful here. My new battery was shorter that the battery bracket/box was designed for. I had to put a piece of wood block, put there by some previous owner, back in the bottom bar of the battery box to raise the new battery up high enough so that it would not fall out or tilt up against the propeller shaft tube of the drive train. I used a universal battery hold-down kit to secure the battery. I added an additional "I" shaped universal hold-down bracket on the bottom of the car's battery box and secured them with the fasteners that came with the hold-down kit.

The existing positive cable was not really long enough and was pulling on the old 6 volt battery and damaged the post. I replaced the cable, which goes up to the starter button on the floor board, with one of proper length. I used a piece of thick treated rubber next to the positive cable/post to make sure vibration does not cause it to make contact with the battery box. Once all of this was secure, I found out what a difference the 12 volt system makes. Now I can install the boom-box and the air conditioner. Oh, we have a touring car. I'll just install the air conditioner. A boom-box is too noisy.

Submitted by Don Warner

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