Car Care
High-Performance Ignition Upgrade
MSD-6AL Installation Steps and Tips
Created by Bill Van Der WoudeLet's admit it. Nearly anyone who can identify their tools by name can install aftermarket parts on their vehicle. Be it an intake, an ignition system, or something as simple as plug wires, it really doesn't take a genius to toss out the old and install the new. The challenge, it seems, is to install the parts in such a way as to make their appearance nearly invisible. Like a good haircut, we prefer add-on aftermarket parts to go unnoticed. We like the stock look, but prefer the modified performance.
Fair Game
There are those who would call an attempt to hide performance modifications deceptive, even dishonest. Remember, those are the same folks that are taking mental notes, and planning on doing the same type of things to their vehicle. All's fair in love and hot rodding.
The MSD-6AL system is synonymous with performance vehicles. There are very few high performance vehicles that do not have some sort of ignition system upgrade, and MSD leads the field in ignition technology. We chose the 6AL box for several reasons; the main being it's built-in Adjustable Soft Touch Rev Controller capable of producing a load-free rev limit that is within one percent of the selected rpm. Various modules are available in 100-rpm increments to match your specific needs.
Rev Limiter
Any vehicle, be it modified or stock, can benefit from a rev limiter. Many of today's new cars come with rev limiters right from the factory. Consider it cheap insurance. The 1973 Pontiac Firebird Formula receiving this install is a 4-speed car, and will be driven hard at the track. If something in the driveline were to fail, the rev limiter could theoretically save the engine if the driver were slow to react.
The factory parts that are removed, namely the module, condenser and wiring harness, are small enough that they can be kept in a zip lock bag and stored in the trunk. Again, consider it cheap insurance. My reasoning is, although we have not heard of an ignition system failing, if the box were to malfunction, it would take just a few minutes to return everything back to stock, and keep the car on the road.
The MSD 6 Series ignitions feature a capacitive discharge design. In plain English, this means that a capacitor is quickly charged (within one millisecond) and the voltage sent to the coil is always at full power, even at high rpm. The stock inductive system can actually lose some of its power at high rpm due to the coil's inability to reach full capacity. The result is a loss of power, or even a top-end miss that can be nearly impossible to diagnose.
Plan Your Prep
The only way to successfully begin the stealth installation of any part is planning. Know your goals, and be willing to put in a little more work to achieve the desired results. The most difficult aspect of this particular install was deciding on the placement of the box. To keep with the stealthy image, it had to be concealed from view, yet accessible enough to change the rpm modules. The older cars are much less cluttered under the hood than today's vehicles, so a little ingenuity was required. After a few days of test fitting, surfing the Internet for ideas, and getting opinions from other folks with similar interests, the final location was decided on.
The inner fender of the '73 Formula is steel, which will provide a secure mounting point. It will also shelter the box from the elements, as well as destructive underhood heat. The only real issue to consider is its accessibility. We wanted it on the driver's side, so there were only two choices. The first was to mount it on the rear of the inner fender, just below the hood hinges, or towards the front, where the factory air inlet tube resides. Mounting it up front, and grinding the air inlet for clearance was the easy winner, as it would conceal the box from all but the most discriminating eyes, and allow easy access to the modules.
Once the battery, airbox, and other miscellaneous parts were removed from the vehicle, the installation itself was quick and easy. The instructions provided by MSD are excellent, and very easy to follow. If we had decided to mount the box in plain sight, the entire process would have taken no more than an hour.
One great tip on finalizing a stealth installation is the use of older convoluted tubing. We've seen some great hidden locations revealed by the brand new wire running in plain sight. Collecting an assortment of grungy tubing salvaged from any number of vehicles resting at the local recycling yards, comes in handy. Nothing hides new wires better than old tubing in a stock appearing performance vehicle. Keep in mind that even the most hidden of installations will inevitably be pointed out by an alert enthusiast at some point. Just tell them the modification they found is the one most folks find first—that'll keep them guessing.
Tools
Standard and Phillips head screwdrivers, wire strippers, grinder, drill, 3/16" drill bit
Install time
2.5 - 3 Hours
Pre-Installation
Step 1 — Disconnect the battery. This should be an obvious one. We will be toying with the cars ignition system, and to reduce the risk of shock or damaging the vehicle's electrical system, the power should be off. Unhook the negative cable first, and re-connect it last.
Step 2 — Find a location for the box. It should be mounted in a location that will keep it protected from moisture, and allow adequate air flow for cooling. If you are installing the box with no regard to who sees it, this is an easy step. If you are going for the stealthy approach, this can be the most time consuming. The box needs to be hidden from view, yet still accessible enough for you to change the plug-in modules. This actually doubled our estimated install time of 1.5 hours. As you can (or can't) see, the end result was worth the time invested.
Step 3 — Check your parts! There is nothing more frustrating than being nearly done with an install, only to find that the one piece you need to finish it has vanished. MSD is kind enough to have all the small parts you'll need in a sealed bag, but it never hurts to be double check. If it's been a while since the spark plugs and wires have been attended to, this is a great time to switch them out. It is important to note that solid core spark plug wires cannot be used with an MSD ignition. It is also recommended you change the vehicles cap and rotor.
Step 4 — Check for compatibility. The instructions include a list of compatible coils and tachometers that will work with the 6 series ignition systems. If your tach or coil is not compatible, MSD offers adapters.
Step 5 — Test fit your location. MSD includes a lengthy harness (P/N 8860), which should allow the stealthy installer to hide the box nearly anywhere under the hood. The box can be installed in any position, except directly upside down. If you are mounting it in the engine compartment, be sure it is away from direct heat sources, and keep the wires away from sharp edges.
Step 6 — The Soft Touch Rev Limiter that is built into the MSD-6AL box is designed to work on an 8-cylinder engine. If you are installing this unit on a 4 or 6 cylinder vehicle, the cylinder select device on the side of the box must be modified. Detailed instructions are included.
Installation
Step 1 — Read the instructions thoroughly to fully understand what it is you are trying to accomplish, and determine which wiring schematic is correct for your application. This vehicle's distributor has already been updated wit a later model HEI system, so we will be using the "HEI 4-pin Module" diagrams.
Step 2 — Remove the distributor cap and rotor. Be sure to mark any and all wires that are removed.
Step 3 — Remove the GM ignition module, condenser, and cable harness.
Step 4 — Install MSD p/n 8861 wire harness. This harness will replace the parts removed in step 3. Be sure to use the provided wire clamps to keep the installation clean, and the wires away from moving parts. Use the provided grommet to ensure a weatherproof seal. These trigger wires should be routed separate from the other wires, especially spark plug wires. It is best if they are routed along a ground plane such as the engine block or firewall to create an electrical shield, and prevent unwanted electrical interference.
Step 5 — Install the rubber insulator and MSD p/n 8412 Low Resistance Bushing between the distributor cap and coil. The low resistance bushing allows the secondary voltage to be transferred from the cap to the rotor without excessive heat build-up.
Step 6 — Connect MSD p/n 8860 harness to the connection now leaving the distributor provided on wire harness p/n 8861 installed in step 4.
Step 7 — Install the MSD box in the location of your choice. Mark the mounting holes, and use a 3/16" bit to drill the holes for the required vibration mounts. Install the vibration mounts then install the box.
Step 8 — Connect MSD p/n 8860 harness to the magnetic pickup connector coming out of the MSD box.
Step 9 — Wire connections are as follows. Remember, the wires should be routed away from direct heat sources such as exhaust manifolds, headers, and any sharp edges.
Heavy Red Wire
Connects directly to the positive terminal of the battery.
Heavy Black Wire
Connects to a good ground, either the negative terminal of the battery, or to the engine.
Black Wire
Connects to the "C+" terminal of the distributor cap
Orange Wire
Connects to the "B+" terminal of the distributor cap
Red Wire
Connects to a switched 12 volt source (such as the ignition key or switch)
White Wire
Not used in this application. It should be taped off and hidden away, unless you plan on using it as a theft deterrent kill-switch.
Step 10 — Reconnect the battery. Connect the positive cable first, and the negative cable last to reduce the risk of dangerous sparks