MSD 6520 Digital 6-Plus Ignition Control Installation User Manual

Msd digital 6 plus ignition control

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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

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

Parts Included:

1 - MSD Ignition

1 - Harness, PN 8860

1 - Parts Bag, ASY 19864

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.
Important: When installing a Digital Series Ignition, the timing must be checked and reset to your engine's



This Ignition features a built-in Soft Touch Rev Control with two different rpm limits. The Soft Touch circuitry

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.

You can select two rev limits; one for a low limit that can be used when staging the car, and another limit

for top end overrev protection. Both rpm limits are adjusted in 100 rpm increments with the sealed rotary

switches on the side of the ignition. Using and programming the Two Step is explained in detail on page 6.


Note: Do not use digital or dial back timing lights.


The MSD Digital 6 Plus uses 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 accurate timing signals to within 1° and 1% of the rpm limits. The circuits and

controller of the Digital 6 Plus have been thoroughly debounced and isolated to create protection against

Electro Magnetic Interference (EMI).


The MSD Digital 6 Plus features 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 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 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 is always at full power even at high rpm.


The MSD 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 3,300 rpm there is simply not enough “time” to fire the spark plug more than once, so there is only

one powerful spark.

MSD Digital 6 Plus Ignition Control

PN 6520

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