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When you are a young gearhead, one of the first things you are taught to inspect and address in any vehicle you are new to is the ignition system. Look at the spark plugs and check the wires, because if the fuel isn't being lit, you aren't going anywhere. Sound familiar? Maybe from shop classes or an older relative? It was sage advice because after so many years and so many miles, even the most durable ignition system can wear out. Providing a constant, solid spark to the air and fuel in the cylinders takes a toll after decades of use, but unless you burn through a plug wire or have something equally as catastrophic happen, it is difficult to tell when the system is tired. As these components wear out, the performance drop-off is a gradual curve. You likely won't notice it until after you replace the worn-out parts. Then you'll realize just how much power was missing.
This 1976 Dodge Charger is such an example. After over four decades of use, the original ignition system was still in place, and the spark plugs and wires were looking positively ancient. The distributor probably hadn't moved ever since it was installed on the Windsor, Ontario assembly line. Performance suffered as a result. Let's be very honest: this is a stock 1970s Chrysler 360 under the hood of this big Dodge that only packed 180 horsepower when equipped with a two-barrel carburetor. It's not a fire-breather. But fresh ignition parts, combined with a strong electrical current feeding that ignition, should at least put every last one of those horses to use. We opted to swap out the coil, distributor, spark plugs, spark plug wires, and after considering the source of our ignition system's 12v feed, decided upon a completely new system for the B-body Mopar.
When working on any electrical system or component, disconnect the battery! You do not want to become an integral part of an electrical circuit. We opted for the "better safe than sorry" plan of removing the battery from the car altogether.
Like we suspected, the original canister-type ignition coil was still mounted to the Charger's intake manifold. After forty-something years, it was still providing the current to the distributor for the plugs. But those same years saw a stock Chrysler coil laid on it's side, resting in a mount over the intake manifold, in a position where it was seeing considerable vibration. That's not a healthy recipe for most coils. But none of that would bother an MSD Blaster High Vibration coil. The Blaster High Vibration coil's primary and secondary windings are completely potted in a premium-grade epoxy, which protects the internals from high and low-frequency vibrations. And since the Blaster High Vibration has a CARB E.O. number, it's legal for the street.
With the coil and associated bracketry removed, we noticed that the canister mounts were painted over. One main engine ground runs from the firewall to the rearward mount, so the mounts were hit with a wire brush to provide a metal-on-metal mounting surface.
Getting some additional spark into the 360's cylinders meant that the original distributor was no longer going to hack it. While there was nothing inherently wrong with the stock Chrysler distributor, we wanted to add robustness and tunability to the ignition system and, at the same time, remove some of the complication out of the factory ignition wiring. The MSD Ready-To-Run distributor is perfect for our situation: it features a built-in ignition module that is maintenance-free, requires only three wire connections to run (and has a tachometer feed wire built-in), and drops right into place. All you have to do is remember where the rotor button was located so you don't put the distributor in 180-degrees out and remember what cylinder the rotor was pointing at before you removed the stock unit. Taking notes (or even better, a photo with your phone) will really come in handy.
Wiring up the Ready-To-Run distributor is simple: the black wire with a ring terminal goes to a ground (in our case, the firewall ground). The red wire connects to the coil's positive terminal and the orange wire connects to the coil's negative terminal. Since we are not using a tachometer at this point in time, the gray wire was zip-tied to the main wire bundle to keep it safe for later use. We also replaced the vacuum advance hose while we were in here...the old one was so cooked that it snapped in half.
It's been a dependable unit, but it is time to retire Old Faithful here. This is also time to remind you to clean up around the base of the distributor before you even think of grabbing the distributor wrench. You don't want sludge, dirt, leaves, bugs, or whatever else is back there dropping into the engine.
Another reminder: remember where your rotor button was at BEFORE you remove the distributor to spare you pain and anguish. We were pointing at #5, so we placed a strip of aluminum tape over the wire bundle to mark where to aim the MSD distributor's rotor button.
There are a couple of things to address on the Ready-To-Run distributor before you drop it into the engine. First up is setting the centrifugal advance curve. This is done by using a combination of two springs that control the rate the mechanical advance arms move out, which you can find once you remove the rotor button cap. From the factory, the Ready-To-Run is equipped with two Heavy Silver springs. In the accessory pack that comes with the distributor, you will also have a set of Light Silver and Light Blue springs. Use the installation instructions (found either in the box or on the distributor's page on Holley.com) to determine what combination works best for you. Since this engine is dead-stock, we want a slow curve, so we stuck with two Heavy Silver springs.
The second item to check before inspection is the Advance Stop bushing, found underneath the centrifugal advance arms. The distributor comes with a Blue (21-degree) bushing installed, and in the accessory pack there will be five more sizes, allowing advance stops anywhere between 18-degrees to 28-degrees. To change the bushing, remove the locknut and washer, then swap the bushing out and replace the washer and locknut.
Just like the Blaster coil, the MSD Ready-To-Run distributor has a CARB E.O. number, making them legal to install on vehicles newer than 1967, even in California. Don't forget to put those stickers on!
Next on the replacement list: those old, gray plug wires. They just ain't like they used to be. With no idea of their age, we had to guess based upon the other parts removed and the condition of the spark plugs. When we had to break out a 3-foot long breaker bar to get the spark plugs out of the head, we assumed that these wires had to go. We replaced them with MSD's Super Conductor Spark Plug Wire Set for Chrysler LA small-blocks with MSD distributors. Besides looking good, these 8.5mm plug wires only have 40-50 ohms of resistance per foot of length, which is the lowest of any helically-wound spark plug wire. In that same twelve inches of wire, there is forty feet of conductor wrapped in, which combined with the ferro-magnetic impregnated center core, creates an effective electromagnetic interference (EMI) choke. The EMI stays within the wire instead of spreading out to other electronic items within the car. On our Charger, that's not really an important point, but once you get later into the 1970s and newer, that becomes a very big deal, especially in cars with pre-OBD computer management systems.
We did run into a minor issue with the Super Conductor Plug Wires. On the #1 Cylinder, the "stovepipe" that feeds hot air from the exhaust manifold to the air cleaner was in constant contact with the boot of the plug wire. Since this car gets stored during late fall and winter, having this stove isn't a necessity. We removed it and placed it into storage...just in case 1976 Chargers suddenly spike in value.
The final portion of our weekend upgrade for the Charger involved figuring out how to power the ignition. We wanted to have a stable 12 volts going to our new distributor, and we didn't have a lot of faith in the factory ballast resistor to do that. Since we'd been battling a stable power feed issue with this car's in-tank electric fuel pump, we decided to nip both problems in the bud by using an MSD High-Current Solid-State Relay to provide the 12-volt power to both the ignition system and the fuel pump. Even for the electrical-averse, wiring up the Solid-State Relay is a breeze. In fact, the most difficult time we had with this whole system was figuring out where we could mount it!
We wanted the Solid-State Relay to be out of the way, yet close to the battery for a short feed wire and accessible enough that we could monitor the LED indicators. That location wound up being about five inches behind the battery on the left-front fender lip. We had to remove the Charger's data plate to fit it properly, but this allowed us to deal with a spot of unforeseen rust on the car. Win-win, in our eyes.
While we would have to drop the relay down to add any wires, the location is neat, clean and is protected from water spray from the road or grille.
This image showcases the simplicity of wiring up the Solid-State Relay. The BATT terminal feeds 12 volts directly into the relay. The red wire in Channel 1 is the power supply wire (in this case, for the fuel pump). The black ground wire ("G") is the relay's ground and is required for operation. And the green wire in the 12-volt activation Channel 1 slot is a 12-volt key-on power supply that triggers the pump's on-off function. If the pump was ground-activated, it would be in the Channel 1 activation terminal (same section as the "G" ground).
Note the LED lights at the channels...these are diagnostic indicators that quickly indicate what that particular channel's status is. Two green LEDs means power is on and all is well. Both off means there is no power. A Fault-Output "On" condition (in this picture, the left LED lit while the right is off) means that 12 volts was directly applied to the output, or that the item was faulty. Fault-Output "Off" (here, the right LED lit with the left off) is due to either over-current, missing BATT power or missing ground.
With the ignition system fresh, a new set of spark plugs in the cylinders, and the Solid-State Relay providing clean, uninterrupted power to everything, our Charger's behavior has improved considerably. There hasn't been so much as a hiccup from the fuel system and even on a hot summer day, there is no fault to find. We've gone from not driving the car out of town to taking the car on good day-trips, and besides cruising happily along at Interstate speeds (unthinkable before), we've seen fuel mileage of about 20 MPG on such trips! Start-up is instant, downshift power is instant, and idle is as smooth as butter.