MSD 7222 Installation

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.

Parts Included:

1 - MSD 7AL-2 Plus Ignition 1 - White Wire
1 - Mag Pickup Extension Harness, PN 8860 1 - Red Wire
1 - Mag Pickup Adapter Harness, PN 8859 4 - Vibration Mounts and Hardware
1 - Coil Harness, PN 8863 4 - RPM Modules: 3K, 7K, 8K and 9K

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

8 None
6 One
4 Two
2 Three

Figure 1 Cylinder Programming.

Cut loops

Remove cap

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2 INSTA L L A T I O N I N S T RU C T I O N S

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 [phone].

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.

TACH
TERMINAL

SPARK PLUGS AND WIRES

Spark plug wires are very important to the operation of your ignition system.

Figure 2 Tach Terminal.

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 1-8-4-3-6-5­7-2. 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.

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INSTA L L A T I O N I N S T RU C T I O N S 3

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
that, you can then experiment with the plug gap to obtain the
best performance. The gap of the plugs can be opened in

0.005” increments, then tested until the best performance
is obtained. MSD judges the plug gap by compression and
components:

Note: A larger plug gap taxes the cap, rotor and spark plug
wires. Always inspect the cap and rotor to make sure
they are in good condition.

Compression Spark Plug Gap

Up to 10.5:1: 0.050" - 0.060"

10.5:1 - 13.0:1: 0.040" - 0.050"
Above 13.0:1: 0.035" - 0.040"

These examples are just starting points to

get you going in the right direction. Every

application is different and should be

tested and tuned.

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.

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4 INSTA L L A T I O N I N S T RU C T I O N S

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.

Terminal Wire Function

COIL +

COIL -

BAT -

BAT +

TACHTACH

2-STEP

IGNITION

POINTS

ORANGE

BLACK

HEAVY
BLACK

HEAVY
RED

DARK
BLUE

RED

WHITE

Connects to the positive (+) terminal of the coil.This is the only wire that
makes electrical contact with the coil positive terminal.

Connects to the negative (-) terminal of the coil. This is the only wire that
makes electrical contact with the coil negative terminal.

This wire connects to a good ground, either at the battery negative (-) terminal
or to the engine.

This wire connects directly to the battery positive (+) terminal or to a positive

battery junction or the positive side of the starter solenoid. Note: Never
connect to the alternator.

This terminal delivers a 12 volt square wave signal as an output for a
tachometer or devices that require an rpm signal.

When this terminal is connected to 12 volts, RPM module 1 is active. When
there is no 12 volts, RPM module 2 is active.

Connects to a switched 12 volt source. Such as the ignition key or switch.

This wire is used to connect to the points, electronic ignition amplifier output
or to the Yellow wire of an MSD Timing Accessory. When this wire is used,

the Magnetic Pickup connector is not used.

VIOLETMAG +

GREENMAG -

These wires are routed together in one harness from the Magnetic Pickup
connector. The connector plugs directly into an MSD Distributor or Crank
Trigger. It will also connect to factory magnetic pickups or other aftermarket
pickups (Figure 4). The Violet wire is pos. (+) and the Green is neg. (-).

When these wires are used, the Points Terminal is not.

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INSTA L L A T I O N I N S T RU C T I O N S 5

Noise Capacitor: MSD offers a Noise Capacitor or Filter to
help eliminate EMI noise. This capacitor, PN 8830, will also
protect the MSD and accessories from voltage and current
spikes.

ROUTING WIRES

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

Common Mag Pickup Wires

Distributor Colors

Mag+ Mag­MSD Org/Blk Vio/Blk
MSD Crank Trigger Org/Blk Vio/Blk
Ford Orange Purple

46/48000

Accel
Accel
Chrysler Org/Wht Black
Mallory Org/Blk Vio/Blk

Series Org/Blk Vio/Blk

51/61000

Series Red Black

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

Figure 4 Common Mag Pickup Wires.

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 [phone], 7 - 6 mountain time.

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