The '79 Chevy Big 10 we threw together at the last minute to run cross-country in Rod & Custom magazine's 2007 edition of Americruise has proven to be an excellent platform for a long-term test truck. As this is being written it is early September and the '79 has already logged an additional 3,000 miles on top of the 5,200 miles we clocked last June while attending Americruise.
As those of you who are familiar with the Chevy's initial buildup can attest to, there were several mechanical areas that had to be skimmed over in order to be ready in time to leave. When initially evaluating the truck's electrical system, it looked to be in pretty good condition. The battery was relatively new, and the alternator was reported to have been replaced right before we got the truck. Of course, a visual inspection is only the first half of a good checkup; we hooked up a voltage meter to the battery at rest and it was storing 12.8 volts, a shade over the desired optimum reading of 12.5 volts. The next test was to verify the reading given on the stock Chevy voltage gauge was correct, and sure enough, the cutoff of our rebuilt alternator with an integral voltage regulator was right at 14.9 volts. Thankfully, as the passing of time would prove, the charging system we left with served us well, but the odds were 50/50 at best that things would stay that way.
That said, we'll move on to why anyone would remove an alternator that was living up to its charging duties to replace it with another one such as the PowerStar alternator from the folks at Painless Performance in Fort Worth, Texas. In the case of our '79 Chevy Big 10, the main reason was to take advantage of the PowerStar's ability to deliver high amps at low revolutions. To cite an example, the Painless PowerStar delivers a whopping 70 amps at only 700 rpm, which in the case of our '79 Chevy is right around idle with the air conditioning on in gear while stopped at a light.
Before we installed the Painless PowerStar, idling at a light with the air conditioning on meant our A/C fan's blower speed would drop as well as the cold-air output. In a heat-sink fishbowl like our late-model C-10 with factory air, it wasn't long before the stock A/C's diminished output at idle translated into a sweat-induced state of discomfort.
After installing the Painless PowerStar, our theory was confirmed: The higher amperage at idle would maintain the A/C while the truck was sitting at a light, crawling through traffic, or cruising at a truck run.
In addition to offering an immediate cure to our A/C problems, we chose to install the PowerStar alternator in anticipation of installing the Clarion sound system also covered in this issue, as well as ensuring the onboard HGM computer for our 4L60E GearStar automatic transmission wouldn't suffer a failure due to an inadequate supply of current.
See, isn't it funny-we didn't even realize all the added demands our customized C-10 makes on the charging system until we started thinking about it. Installing Painless Performance's PowerStar alternator was a pretty simple procedure that didn't take more than a couple of hours to complete. As with any specialized electrical component, there are some special precautions you should take during installation, but don't worry, we've got you covered in the following photos and captions.
The '79 came to us with a...
The '79 came to us with a basic discount auto parts-type rebuilt alternator complete with Chinese-made bearings and a plastic replacement cooling fan. Before we installed the Painless Performance low-rpm, hi-amp alternator, there was excessive noise reverberating from what we believed to be either the rebuilt alternator or the smog pump.
The first step was to disconnect...
The first step was to disconnect the ground cable at the battery. In this photo the opposite end of the ground cable is also being disconnected, but doing this alone will leave a secondary ground wire, and the 12-volt positive cable will still be hot.
In the overall picture, taking...
In the overall picture, taking the time to remove or reposition parts that deter access to removing the alternator (as opposed to creating forced clearance between other parts) will pay off with a cleaner job and better results.
There are only two bolts that...
There are only two bolts that hold the alternator on. The top bolt is around 1 1/2 inches long, and the bottom bolt is much longer (I forgot to measure it), spanning the distance from the alternator's face to beyond the alternator's rear face and extending into the engine block. Our fan belt was new, but if yours isn't, this is the time to replace it.
It is always a good idea to...
It is always a good idea to compare the old part with the new one before attempting to install it. The only outward physical difference between our old alternator and the new Painless PowerStar was the old rebuild's threaded ear to retain the lower mounting spacer.
We cleaned the lower spacer...
We cleaned the lower spacer with an ecologically friendly solvent, and then checked the factory-original GM lower spacer for fitment to the Painless PowerStar.
Upon checking the lower mounting...
Upon checking the lower mounting bolt to see if it would fit, we discovered the Painless PowerStar alternator comes with a sleeve-type bushing to guarantee a tight fit. In our case, the bushing was too tight and had to be drifted out before installation.
The final step before installing...
The final step before installing the PowerStar alternator into place on the '79 was to completely assemble it and make any last-minute checks. We discovered the threads on the mounting bolt were slightly crossed. We chased the threads with a die nut and coated them with white lithium grease.
The PowerStar alternator features...
The PowerStar alternator features a unique adjustable voltage regulator with a range of 13.5-18.5 volts. It is adjusted by turning this little Phillips head screw while observing a voltage meter (on board or handheld).
For most C-10 applications,...
For most C-10 applications, the PowerStar alternator is a true one-wire system that only requires the main 12-volt lead (A). That said, the plug (B) with the red and black wires that we unhooked from the rebuilt alternator did not have to be reconnected to the PowerStar alternator.
It can't be stressed enough...
It can't be stressed enough that checking to make sure things are right before final tightening occurs will ensure a perfect installation. Notice the encircled area reveals a gap between the stock mounting bracket and the PowerStar alternator. A common mistake would be to overtighten the mounting bolt to adjust for this. At best, the pulleys wouldn't run true and there would be premature bearing wear or an electrical failure.
For anyone who likes to do...
For anyone who likes to do custom work on their truck, it is a good idea to keep an inventory of miscellaneous spacers and such to use at times like this. Not that it would have been all that hard to make a new spacer, or use the backyard mechanic's favorite cure, a stack of flat washers.
The best high-end electrical...
The best high-end electrical components use real gold to make their connections. The same is true for the one-wire lead that connects the PowerStar to a gold terminal.
Look closely where the screwdriver...
Look closely where the screwdriver tip is pointing and you will notice the terminal end on the 12-volt one-wire hot lead twisted into the alternator case as it was tightened, creating a dead short. It is essential to make sure this has not occurred or severe damage will result to the PowerStar alternator; it is known as "brand-new alternator charcoal surprise."
The last step was to adjust...
The last step was to adjust the alternator/smog pump belt tension, and then make one last visual inspection of the belt's alignment.
We lied; the last step was...
We lied; the last step was to make sure the battery was fully charged before we started the truck (damage can occur to the alternator if it isn't), and then admire the Painless PowerStar in all its virgin aluminum glory.
The proof is in the pudding....
The proof is in the pudding. As soon as we finished installing our Painless PowerStar, we cruised out to the Route 66 rendezvous in San Bernardino, CA, and cruised all day long at 5 mph with the A/C blasting; our new Clarion sound system, complete with an amplifier, cranked up; and the voltmeter needle never budged.