Electric Fan Upgrade

The 1966 Mustang has a fixed blade fan, attached directly to the pulley that turns the water pump. These fans are noisy, think of it as an airplane prop out in front of your engine. The faster it turns the louder it gets. Coincidentally, this is the opposite of what is needed for cooling. The fan is most critical when the car is stopped, and there is no air being naturally forced over the radiator to cool the engine. At speed, when the engine is running at higer RPMs the air from the car rolling down the road pushes over the radiator and cools it nicely.

Old fixed blade fan

 Over the years, there have been a number of improvements to cooling methods. There have been slip clutches on the fan shaft so that it will start to slip at higher RPMs and reduce noise. There have been flex blades, fan blades that flatten out and don't slap as much air at higher RPMs. By far, the best improvement has been the electric fan. Electric fans are controlled by a thermostat sensor attached to the water pump. When the temperature of the coolant hits the upper limit, the thermostat kicks on an electric fan until the temperature drops below the lower limit. It is significantly quieter, and more efficient since it is only running when it is required.

It took a bit of juggling, since the new fan was just a hair thicker than the space we had between the engine and the radiator. We ended up placing the fan in front of the radiator, and setting it up in "pusher" mode. This has the side effect of making the engine compartment just a hair cleaner.

Electric fan in place, in front of radiator

We wired up the sensor and fan relay and were ready to test out the new upgrade.

1 Wire 3G Alternator

So we are having trouble with the Mustang running rough. It's cold outside, but there seems to be more to it than that. After a bit of engine tuning, we found that the car was running fine until we turned on the headlights. Then the engine would bog down, rev up, bog down, rev up. Turn the lights back off and the car returns to running well. So, this would be at least the 3rd issue we have had with the alternator, battery and external voltage regulator. We have replaced wiring harness connectors, the regulator, the alternator, and the battery over the past 2 years. We now have a bit of experience under our belts, and I did some research on a 1 Wire Third Generation Alternator conversion. Essentially, this is a swap of the original alternator at 55Amps with an alternator from a modern Third Generation Mustang with an internal regulator and outputting 130Amps.

So we ordered the wiring harness required off of ebay, and a new alternator off of Amazon.

One tricky part of this upgrade, was that we would have to replace the serpentine pulley from the modern alternator with the original v-belt pulley from the classic Mustang. We would love to upgrade to a modern serpentine pulley system as well, but that would require replacing the water pump pulley, and the crankshaft/balancer pulley. We have not been able to find suitable replacements so far, and the upgrade kits for this are in the $300 and up price range. We'll just keep it classic for that price.

Once we got that in place, it was time to install the new alternator.

 Here we are, all installed with the v-belt pulley.

Once that was done, we wired up the alternator. 1 Wire in this case, really means 2 wires. 1 wire to the ignition to turn on the alternator coils, and 1 wire to connect the output to the battery. We used some jumper cable wire, and a few good solid connectors and wired this up to the battery, and then on to the starter solenoid for a nice clean and heavy gauge connection.

I can't even count the number of wires that were involved in the old system. 3 at the alternator, a handful at the external regulator, and the output was run through the dash to give a Charge/Discharge gauge readout. We'll replace the Charge/Discharge with something else later, perhaps a 10-16V gauge. At rest, the system is roughly 12V, when the alternator is on, it's somewhere around 13V. If the engine is running and the alternator is not functional, the voltage is somewhere around 11V.