MSD 7AL-2 Plus Ignition
PN 7222
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Note: Solid Core spark plug wires cannot be used with an MSD Ignition.
Note: An MSD cannot be used on vehicles with CD ignitions or distributorless ignition systems.
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Parts Included: |
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- MSD 7AL-2 Plus Ignition |
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- White Wire |
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- Mag Pickup Extension Harness, PN 8860 |
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- Red Wire |
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- Mag Pickup Adapter Harness, PN 8859 |
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- Vibration Mounts and Hardware |
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- Coil Harness, PN 8863 |
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- RPM Modules: 3K, 7K, 8K and 9K |
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WARNING: Before installing the MSD Distributor, disconnect the battery cables. When disconnecting the battery cables, always remove the Negative (-) cable first and install it last.
FEATURES
RPM LIMITERS
The 7AL-2 Plus Ignition is equipped with a 2-step rev control. The Ignition will accept two rpm modules so two different rev limits can be set. One rev limit can be used for overrev protection while the second limit can be activated on the starting line for a lower rpm limit to assist in staging and for consistent holeshots. When 12 volts are applied to the 2-step terminal (2’S’), Module 1 is active. Module 2 is active when there is no 12 volts.
CYLINDER SELECT
This ignition can be used on 2, 4, 6 (even-fire) or 8-cylinder engines. The ignition is set for 8-cylinder operation. To program the unit for other engines, remove the one screw that holds the cover to reveal three wire loops (Figure 1). Cutting a wire loop determines the cylinder selection.
SPARK LED
When the coil fires, current is sensed and this LED will flash. This confirms that the ignition has received a trigger signal and that the coil and ignition are working properly. (If the coil is not connected, the LED will not flash.) When the engine is running, it will appear solid.
Cylinders Loops to Cut |
Remove cap |
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8 |
None |
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6 |
One |
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4 |
Two |
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2 |
Three |
Cut loops |
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Figure 1 Cylinder Programming. |
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INSTALLATION INSTRUCTIONS |
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GENERAL INFORMATION
BATTERY
An MSD 7AL-2 Plus Ignition Control will operate on any negative ground, 12 volt electrical system with a distributor. The MSD can be used with 16 volt batteries and can withstand a momentary 24 volts in case of jump starts. The Ignitions will deliver full voltage with a supply of 10 - 18 volts and will operate with a supply voltage as low as five volts.
If your application does not use an alternator, allow at least 15 amp/hour for every half hour of operation. If the engine is cranked with the same battery or other accessories such as an electric fuel or water pump, the amp/hour rating should be higher.
COILS
The MSD 7AL-2 Plus Ignition can be used with many stock coils and aftermarket coils designed to replace the stock coils such as the Blaster line of coils. For short duration racing, like drag racing, the MSD Pro Power Coil, PN 8201, is recommended. For use on the street or long duration events, use coil PN 8251 or PN 8261. For more information on recommended coils, consult the supplied Coil Application Chart or check with the manufacturer of your coil. If you have any questions concerning coils, contact our Customer Service Department at (915) 855-7123.
TACHOMETERS
The MSD Ignition features a Tach Output Terminal on the terminal strip. This terminal provides a trigger signal for tachometers, a shift light or other add-on rpm activated devices. The Tach Output Terminal produces a 12 volt square wave signal with a 33% duty cycle. Some vehicles with factory tachometers may require a Tach Adapter to operate with the MSD. For more information on Tachometers and MSD Tach Adapters, see the Tachometer Section on page 6. If your GM vehicle has an inline filter it may cause the tach to drop to zero on acceleration. If this occurs, bypass the filter.
SPARK PLUGS AND WIRES
Spark plug wires are very important to the operation of your ignition system.
A good quality, helically wound wire and proper routing are required to get the best performance from your ignition, such as the MSD Heli-Core or 8.5mm Super Conductor.
Note: Solid Core spark plug wires cannot be used with an MSD Ignition.
A helically, or spiral wound wire must be used. This style wire provides a good path for the spark to follow while keeping Electro Magnetic Interference (EMI) to a minimum. Excessive EMI, such as the amount that solid core wires produce, will interfere with the operation of the MSD and other electronics on your car.
Spark Plug Wire Routing: Correct routing of the plug wires is also important to performance. Wires should be routed away from sharp edges and engine heat sources. If there are two wires that are next to each other in the engine’s firing order, the wires should be routed away from each other to avoid inducing a spark into the other wire. For example, in a Chevy V8, the firing order is 1-8-4-3-6-5- 7-2. The #5 and #7 cylinders are next to each other in the engine and in the firing order. If the voltage from the #5 wire is induced into #7 detonation could occur and cause engine damage.
To add more heat protection to your plug wires, MSD offers Pro-Heat Guard, PN 3411. This is a glass woven and silicone coated protective sleeve that you slide over your plug wires. For extra protection of the spark plug boots, MSD offers Pro-Heat Boot Guard, PN 3412.
M S D • W W W . M S D P E R F O R M A N C E . C O M • ( 9 1 5 ) 8 5 7 - 5 2 0 0 • F A X ( 9 1 5 ) 8 5 7 - 3 3 4 4
INSTALLATION INSTRUCTIONS |
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Spark Plugs: Choosing the correct spark plug design and heat range is important when trying to get the best performance possible. Since there are so many engine combinations and manufacturers, MSD does not recommend which plug or gap is exactly right for your application.
It is recommended to follow the engine builder or manufacturer’s specification for spark plugs. With |
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that, you can then experiment with the plug gap to obtain the |
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best performance. The gap of the plugs can be opened in |
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Compression |
Spark Plug Gap |
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0.005” increments, then tested until the best performance |
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Up to 10.5:1: |
0.050" - 0.060" |
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is obtained. MSD judges the plug gap by compression and |
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10.5:1 - 13.0:1: 0.040" - 0.050" |
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components: |
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Above 13.0:1: |
0.035" - 0.040" |
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Note: A larger plug gap taxes the cap, rotor and spark plug |
These examples are just starting points to |
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get you going in the right direction. Every |
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wires. Always inspect the cap and rotor to make sure |
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application is different and should be |
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they are in good condition. |
tested and tuned. |
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MISCELLANEOUS INFORMATION
Sealing: Do not attempt to seal the MSD. All of the circuits of an MSD receive a thick conformal coating of Humi-Seal. This sealant protects the electronics from moisture. If you were to seal the unit, any moisture or water that may seep in through the wiring grommets will not be able to drain and may result in corrosion.
Welding: If you are welding on your vehicle, to avoid the chance of damage, always disconnect both Heavy Power cables of the MSD. (You should also disconnect the tach ground wire too).
Distributor Cap and Rotor: It is recommended to install a new distributor cap and rotor when installing the MSD Ignition Control. The cap should be clean inside and out especially the terminals and rotor tip. On vehicles with smaller caps, it is possible for the air inside the cap to become electrically charged causing crossfire which can result in misfire. This can be prevented by drilling a couple vent holes in the cap. The holes should be placed between the terminals, at rotor height and face away from the intake. If your environment demands it, place a small piece of non-metallic screen over the hole to act as a filter.
Initial Spark: It is normal, yet not very common, for the MSD to produce a spark when the ignition key is turned On. This is due to the capacitor being charged and if the pickup is in the right position, it could trigger the ignition momentarily. This could also occur when installing the positive battery cable.
MOUNTING
The MSD can be mounted in most positions. It can be mounted in the engine compartment as long as it is away from direct engine heat sources. It is not recommended to mount the unit in an enclosed area such as the glovebox.
When you find a suitable location to mount the unit, make sure the wires of the ignition reach their connections. Hold the Ignition in place and mark the location of the mounting holes. Use a 1/4” drill bit to drill the holes. Install the vibration mounts to the ignition and mount the unit.
M S D • W W W . M S D P E R F O R M A N C E . C O M • ( 9 1 5 ) 8 5 7 - 5 2 0 0 • F A X ( 9 1 5 ) 8 5 7 - 3 3 4 4
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INSTALLATION INSTRUCTIONS |
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WIRING
GENERAL WIRING INFORMATION
Wire Length: All of the wires of the MSD Ignition may be shortened as long as quality connectors are used or soldered in place. To lengthen the wires, use one size bigger gauge wire (10 gauge for the power leads and 16 gauge for the other wires) with the proper connections. All connections must be soldered and sealed.
Grounds: A poor ground connection can cause many frustrating problems. When a wire is specified to go to ground, it should be connected to the battery negative terminal, engine block or chassis. There should always be a ground strap between the engine and the chassis. Always securely connect the ground wire to a clean, paint free metal surface.
The 7AL-2 has a ground stud just to the left of the terminal strip. Use this to ground other MSD accessories (Figure 3).
Ballast Resistor: If your vehicle has a ballast resistor in line with the coil wiring, it is not necessary to bypass it. This is because this wire serves only as an On/Off switch. The MSD receives its main power directly from the battery.
GROUND 
Figure 3 Ground Stud.
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Terminal |
Wire |
Function |
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COIL + |
ORANGE |
Connects to the positive (+) terminal of the coil.This is the only wire that |
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makes electrical contact with the coil positive terminal. |
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COIL - |
BLACK |
Connects to the negative (-) terminal of the coil. This is the only wire that |
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makes electrical contact with the coil negative terminal. |
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BAT - |
HEAVY |
This wire connects to a good ground, either at the battery negative (-) terminal |
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BLACK |
or to the engine. |
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BAT + |
HEAVY |
This wire connects directly to the battery positive (+) terminal or to a positive |
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RED |
battery junction or the positive side of the starter solenoid. Note: Never |
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connect to the alternator. |
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TACH |
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This terminal delivers a 12 volt square wave signal as an output for a |
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tachometer or devices that require an rpm signal. |
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2-STEP |
DARK |
When this terminal is connected to 12 volts, RPM module 1 is active. When |
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BLUE |
there is no 12 volts, RPM module 2 is active. |
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IGNITION |
RED |
Connects to a switched 12 volt source. Such as the ignition key or switch. |
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POINTS |
WHITE |
This wire is used to connect to the points, electronic ignition amplifier output |
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or to the Yellow wire of an MSD Timing Accessory. When this wire is used, |
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the Magnetic Pickup connector is not used. |
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MAG + |
VIOLET |
These wires are routed together in one harness from the Magnetic Pickup |
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MAG - |
GREEN |
connector. The connector plugs directly into an MSD Distributor or Crank |
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Trigger. It will also connect to factory magnetic pickups or other aftermarket |
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pickups (Figure 4). The Violet wire is pos. (+) and the Green is neg. (-). |
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When these wires are used, the Points Terminal is not. |
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M S D • W W W . M S D P E R F O R M A N C E . C O M • ( 9 1 5 ) 8 5 7 - 5 2 0 0 • F A X ( 9 1 5 ) 8 5 7 - 3 3 4 4
INSTALLATION INSTRUCTIONS |
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Noise Capacitor: MSD offers a Noise Capacitor or Filter to |
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help eliminate EMI noise. This capacitor, PN 8830, will also |
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Common Mag Pickup Wires |
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protect the MSD and accessories from voltage and current |
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Distributor |
Colors |
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spikes. |
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Mag+ |
Mag- |
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ROUTING WIRES |
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MSD |
Org/Blk |
Vio/Blk |
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MSD Crank Trigger |
Org/Blk |
Vio/Blk |
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The MSD wires should be routed away from direct heat sources such as exhaust manifolds and headers and any sharp edges. The trigger wires should be routed separate
from the other wires and spark plug wires. It is best if they are routed along a ground plane such as the block or firewall
which creates an electrical shield. The magnetic pickup wires should always be routed separately and should be
twisted together to help reduce extraneous interference (the harness supplied is already twisted).
The chart shows the polarity of other common magnetic pickups. If using a different magnetic pickup, use the MSD 2-Pin connector, available as PN 8824, for a direct plug-in installation.
WARNING: The MSD 7 Series Ignitions are capacitive discharge ignitions. High voltage is present at the coil primary terminals. Do not touch the coil or connect test equipment to the terminals.
PRESTART CHECK LIST
•The only wires connected to the coil terminals are the MSD Orange to coil positive and Black to coil negative.
•The small Red wire of the MSD is connected to a switched 12 volt source.
•The MSD power leads are connected directly to the battery positive and negative terminals.
•The battery is connected and fully charged if not using an alternator.
•The engine is equipped with at least one ground strap to the chassis.
TROUBLESHOOTING
Every MSD Ignition undergoes numerous quality control checks including a four hour burn-in test. If you experience a problem with your MSD, our research has shown that the majority of problems are due to improper installation or poor connections.
The Troubleshooting section has several checks and tests you can perform to ensure proper installation and operation of the MSD. If you have any questions concerning your MSD, call our Customer Support Department at (915) 855-7123, 7 - 6 mountain time.
M S D • W W W . M S D P E R F O R M A N C E . C O M • ( 9 1 5 ) 8 5 7 - 5 2 0 0 • F A X ( 9 1 5 ) 8 5 7 - 3 3 4 4
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