MSD 6A 6201, 6A 62013, 6AL 6425, 6AL 64253 Installation Instructions Manual

INSTALLATION INSTRUCTIONS

1

MSD Digital 6A and 6AL Ignition Control

6A - PN 6201/62013, 6AL - PN 6425/64253

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Parts Included:

1 - MSD Ignition
1 - Harness, PN 8860

WARNING: During installation, disconnect the battery cables. When disconnecting the battery always

remove the Negative cable rst and install it last.

1 - Main Harness
1 - Parts Bag

6AL ONLY

4 - Vibration Mounts
1 - Screwdriver

Note:

Note: If you're triggering an aftermarket EFI system with the Gray wire of the MSD, see page 5 to

Important: When installing a Digital Series Ignition, timing will be affected, reset to your engine's

The Carb label supplied is required to aid in passing the California Smog Check program. This label
must be installed in an underhood location that is readily visible.

deactivate the tach verication feature.

specications.

OPERATION AND FEATURES

DIGITAL OPERATION

The Digital 6A and 6AL use a high speed RISC microcontroller to control the ignition's output while
constantly analyzing the various inputs such as supply voltage, trigger signals and rpm. The high
speed controller can make extremely quick compensations to the output voltage, multiple spark
series, timing and rpm limits while maintaining precise timing and accurate rev limiting. The circuits
and controller of the MSD have been thoroughly ltered to create protection against Electro Magnetic
Interference (EMI).

CAPACITIVE DISCHARGE

The Digital 6A and 6AL feature a capacitive discharge ignition design. The majority of stock ignition
systems are inductive ignitions. In an inductive ignition, the coil must store and step up the voltage
to maximum strength in between each ring. At higher rpm, since there is less time to charge the coil
to full capacity, the voltage falls short of reaching maximum energy which results in a loss of power
or top end miss.

The MSD Ignition features a capacitor which is quickly charged with 520 - 535 volts and stores it until
the ignition is triggered. With the CD design, the voltage sent to the coil positive terminal is always
at full power even at high rpm.

MULTIPLE SPARKS

The MSD produces full power multiple sparks for each ring of a plug. The number of multiple sparks
that occur decreases as rpm increases, however the spark series always lasts for 20° of crankshaft
rotation. Above 3,000 rpm there is simply not enough “time” to re the spark plug more than once,
so there is only one powerful spark.

PROTECTION

The Digital 6A and 6AL have a built in reverse polarity protection circuit. This will protect the ignition
in the event of wrong connections.

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2

INSTALLATION INSTRUCTIONS

LED INDICATOR

A red LED is located on the top of the MSD 6AL. It is used to monitor the current status of the 6AL
ignition.

Key power ON-engine
OFF

Key power ON-engine
OFF

Key power ON-engine
cranking

Key power ON-engine
cranking

Note: When the engins is running, the LED will appear to be ON. This is normal and is due to the

rapid ashing of the LED on each ignition ring event.

Note: Solid Core spark plug wires cannot be used with an MSD Ignition.
Note: Do not use digital or dial-back timing lights.

One long ash

One long ash + 5
short ashes

Continuous ashing

No ashing

6AL box is
functioning Normal

6AL box is
functioning Normal

6AL box is
functioning Normal

6AL box is
functional

Rev Limiter verification
function active (ON)

Rev limiter verification
function deactivated (OFF)

LED ashes each time the
ignition res

Check Power, ground and
crank sensor connections

REV LIMITER

The Digital 6AL features a built-in Soft Touch Rev Control that provides a smooth and accurate rev
limit by dropping the spark to individual cylinders. The Soft Touch produces a load-free rev limit that
is within 1% of the selected rpm.The rpm limit is adjusted in 100 rpm increments with the sealed
rotary switches under the black cover on top of the 6AL.

CYLINDER SELECT

The MSD is programmed at the factory for use on 8-cylinder engines. If you are installing it to a different
engine you will have to program the Ignition. This is easily achieved through the cylinder select wire
loops on the side of the ignition. Page 5 outlines setting the cylinder select.

GENERAL INFORMATION

BATTERY

The Digital 6A and 6AL 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 Ignition will deliver full voltage with a supply of 9 - 18 volts.

If your application does not use an alternator, allow at least 15 amp/hour for every half hour of
operation. The MSD uses about .9 Amps for every 1,000 rpm. If the engine is cranked with the same
battery or other accessories such as an electric fuel or water pump are used, the amp/hour rating
should be higher.

COILS

The Digital 6A and 6AL Ignition can be used with most stock coils and aftermarket coils designed to
replace the stock coils. The line of MSD Blaster Coils are great for street and mild racing. For extended
high rpm operation the Blaster HVC, PN 8252 or HVC II, PN 8253, are recommended. For more
information on recommended coils, check with our Customer Service Department at [phone].

TACHOMETERS

The MSD Ignition features a Gray Tach Output wire that provides a trigger signal for tachometers, a
shift light or other add-on rpm activated devices. The Tach Output wire produces a 12 volt square
wave signal with a 20% 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 in-line lter it may cause the tach to drop to zero on acceleration. If this
occurs, bypass the lter.

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INSTALLATION INSTRUCTIONS

3

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 8.5mm Super Conductor Wire. Helically wound wires provide 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. Solid Core spark

plug wires cannot be used with an MSD Ignition.

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 ring 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 ring 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 ring 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 Boot Guard, PN 3412.

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 specication 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.

These examples are just starting points to get you going
in the right direction. Every application is different and
should be tested and tuned.

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" - 0.045"

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 crossre which can result in misre. 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 screen over the hole to act as a lter.

MOUNTING

The MSD 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 glove box.
When you nd a suitable location to mount the unit, make sure the wires of the ignition reach their
connections. Also be sure that the program dials can be accessed. Hold the Ignition in place and
mark the location of the mounting holes. Use a 3/16" bit to drill holes, install the vibration mounts
and mount the ignition.

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4

INSTALLATION INSTRUCTIONS

WIRING

The Digital 6A and 6AL use a main wiring harness that connects to the ignition through a sealed
and locked connection.

Power Leads

Heavy Red

Heavy Black

Red

Orange

Black

Trigger
Wires

White

Violet
and Green
(Magnetic
Pickup
Connector)

These are the two heavy 12 gauge wires and are responsible for getting
direct battery voltage to the ignition. The Ignition is load protected
from reverse battery connections.

This wire connects directly to the battery positive (+) terminal or a
positive battery junction such as the starter solenoid. Note: Do not
connect to the alternator.

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

This wire is responsible for turning the MSD On and Off. Connects
to a switched 12 volt source such as the ignition key or switch. (Max
current draw of .250 mA.)

This wire connects to the coil positive (+) terminal. This is the ONLY
wire that makes electrical contact with the positive coil terminal.

This wire connects to the coil negative (-) terminal. This is the ONLY
wire that makes electrical contact with the negative coil terminal.

There are two circuits that can be used to trigger the MSD Ignition; a
Points circuit (the White wire) and a Magnetic Pickup circuit (the Green
and Violet wires). Only one circuit will be used at a time.

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

wire is used, the Magnetic Pickup connector is not used.

These wires are routed together in one harness as the magnetic pickup
connector. The connector plugs directly into an MSD distributor or
crank trigger. It will also connect to aftermarket pickups. The Violet
wire is positive (+) and the Green wire is negative (-). When these

wires are used, the White wire is not.

Accessories

Gray

Tach output wire. Connects to the tachometer trigger wire or other
rpm activated device.

Red Loop
Blue Loop

These are the cylinder-select wire loops. Cut one loop for even-re
6-cylinders, two loops for 4-cylinders.

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 (12 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 specied
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.

Ballast Resistor: If your vehicle has a ballast resistor in-line with the coil wiring, it is recommended
to bypass it.

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INSTALLATION INSTRUCTIONS

AL 6AL

5

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 from the
other wires and spark plug wires. It is best if they are routed along a ground plane such as the block
or rewall which creates an electrical shield. The magnetic pickup wires should always be routed
separately and should be twisted together to help reduce extraneous interference.

PROGRAMMING

CYLINDER SELECT

The MSD is programmed for operation on 8-cylinder engines.
If installing the Ignition on a different style engine, the number
of cylinders will need to be selected by cutting the cylinder
select wire loops as shown in Figure 1.

REV LIMITER

The rev limiter can be set from 2,000 to 11,000 rpm. To adjust
the rev limiter of the Digital 6AL, remove the black cover next
to the LED by prying up with the supplied screwdriver. The
dial on the left is for 1,000 rpm increments, on the right is for
100 rpm increments.

CYLINDERS WIRE LOOPS
8 No Cut Loops

6 Cut One Loop
4 Cut Both Loops

REV

LIMITER

DIGIT

For a rev limiter in the 10,000 range, set the dials as they
would be for any other RPM but the left dial will use '0'.

Figure 1 Programming the Number of

Cylinders.

To set the rev limiter to 11,000 rpm, put the left dial to '1'
and the right dial to '0'. Setting both rotary dials to '1' will
activate a special function explained below.
Note: The engine can be running as you make adjustments

to the rev limiter function.

REV LIMITER VERIFICATION

The MSD Digital 6AL has an optional built in Rev Limiter
Verication feature. When the key is in the On position (not
cranking or running), an rpm signal is sent to the tachometer
to verify the unit's rev limit setting. With this function users

1,000's

can be sure of their rev limit settings before each drive.
This feature is not activated from the factory. To enable
this feature, follow the procedure below.
Note: It is important to note that this feature should not

Figure 2 Adjusting the Rev Limits.

be used with EFI systems. When activated, an rpm signal is sent to the tachometer. With an
aftermarket EFI system, this could activate the injectors causing a ooding situation.

Enable Rev Limit Verication

1. With the ignition switch in the off position, ground the Gray tach output wire.

2. With the Gray wire connected to ground, turn on power to the ignition without starting the engine.

3. Hold the Gray tach output wire to ground for seven seconds. (AT LEAST ve seconds.)

4. Release the wire from ground before ten seconds have passed.

5. To conrm the process has worked, cycle turn the key On. The tachometer should sweep to the
rpm limit set on the ignition.

100's

As soon as this process is complete the feature will be activated. The Digital 6AL uses the red LED
to help indicate when an adequate amount of time has passed to release the Gray tach wire. The
LED will turn on after the wire has been grounded for ve seconds and will turn off at the 10 second
mark. To deactivate the feature again, repeat the same process.

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6

INSTALLATION INSTRUCTIONS

Playback Tach: If you use a playback tach, be sure to check the high rpm value prior to turning the
key to the On position. When the key is in the On position, the rev limit will be displayed and may
override the tach memory.

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.

• If you are installing on a 4 or 6-cylinder engine, conrm the programming loops have been modied,
see page 5.

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 - 5 mountain time.

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