MSD 6560 Installation

MSD Marine Ignitions

6M-2, PN 6460 and 6M-2L, PN 6560

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Parts Included:

1 - MSD Ignition 3 - Wire Splicers
1 - Harness, PN 64601 2 - Spade Connectors
4 - #8 x 3/4" Screws

WARNING: During installation, disconnect the battery cables. When disconnecting the battery
always remove the Negative cable first and install it last.

Note: Solid Core spark plug wires cannot be used with an MSD Ignition.
Note: An MSD 6M-2 cannot be used with distributorless ignition systems (DIS).

6M-2L Only

3 - RPM Modules, 4,000, 6,000 and 8,000

THEORY OF 6 SERIES IGNITION

CAPACITIVE DISCHARGE

The MSD 6M-2 Series Ignitions feature a capacitive discharge ignition design. The majority of stock ignition
systems are inductive ignitions. In an inductive ignition, the coil must store energy and step up the voltage
to maximum strength in between each firing. 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 to store the energy as it is quickly charged to 460-480 volts. It then
releases all of this energy when the ignition is triggered. With the CD design, the voltage sent to the coil
is always at full power even at high rpm.

MULTIPLE SPARKS

The 6M-2 produces full power multiple sparks for each firing 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 fire the spark plug more than once, so there is only
one powerful spark.

6M-2, PN 6460

The 6M-2 is equipped with a special 4-wire connector that will plug into an optional Rev Limiter, PN 8768. The
Soft Touch circuitry provides a smooth and accurate rev limit by dropping the spark to individual cylinders.
The Rev Limit is adjustable with special rpm modules in incremements of 200 rpm (see page 12).

6M-2L, PN 6560

The 6M2-L has a built-in rev limiter. The rpm limit is adjusted with marine rpm modules (see page 12).

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2 INST A L L A T I ON IN S T R U C T IONS

GENERAL INFORMATION

BATTERY

The 6M-2 Series 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.

COILS

The MSD 6M-2 Ignition can be used with most stock coils and aftermarket coils designed to replace
the stock coils. There are some "race only" coils such as the MSD
Pro Power Coil, PN 8201, that cannot be used with a 6 Series MSD
Ignition Control. 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 side of the
unit. 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 20% duty cycle.
Some boats 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 distributor/coil has an inline filter it may cause the tach to drop to zero on acceleration. If this
occurs, bypass the filter.

Figure 1 Tach Terminal

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 Wire.

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.

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.

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INST A L L A T I ON IN S T R U C T IONS 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:

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"

MISCELLANEOUS INFORMATION

Welding: If you are welding on your boat, 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.

MOUNTING

The MSD 6M-2 can be mounted in any position in the engine compartment as long as it is away from
direct engine heat sources. It is not recommended to mount the unit in a small enclosed area.
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 an 1/8" drill
bit to drill the holes. Use the supplied self tapping screws to mount the box.

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. MSD offers Weathertight connectors and terminals separately.

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.

Ballast Resistor: If your engine has a ballast resistor in line with the coil wiring, it is not required with
the MSD (though it is not necessary to bypass it). This is because the MSD receives its main power
directly from the battery.

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4 INST A L L A T I ON IN S T R U C T IONS

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 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.

WIRE FUNCTIONS

Power Leads

Heavy Red

Heavy Black

Red

Orange

Black

Trigger
Wires

These are the two heavy gauge wires (12 gauge) and are responsible
for getting direct battery voltage to the Ignition. The ignition has an
internal fuse so no fuse is necessary.

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

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

There are two circuits that can be used to trigger the MSD Ignition; a
Points circuit (White wire) and a Magnetic pickup circuit (Violet and
Green wires). The two circuits will never be used together.

White

Violet
and Green
(Magnetic
Pickup
Connector)

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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.

These wires are routed together in one harness to form the Magnetic
pickup connector. The connector plugs directly into an MSD Marine
Distributor. It will also connect to factory magnetic pickups or other
aftermarket pickups. The Violet wire is positive (+) and the Green is
negative (-). When these wires are used, the White wire is not.