6

INSTALLATION INSTRUCTIONS

OPTIONAL WIRING

This Wiring Section details the optional features of the MSD 7AL-3 and

how to wire each system.

START RETARD

The Start Retard of the 7AL-3 is designed to ease cranking on engines

with locked timing, high compression and a lot of advance. The amount

of retard is determined by a plug-in degree module (Figure 8). There

are two different ways to activate this function (Figure 9):

A. Switched 12 Volts

In this set up, the timing is retarded only while the engine is cranking.

Connect the supplied Violet wire from the “Start-Retard” terminal on

the 7AL-3 to the starter solenoid. This way, 12 volts is only applied

when the key or switch is in the cranking position. When the switch

is released, 12 volts is removed and the timing returns to run timing.

B. Constant 12 Volts

In this setup, whenever the ignition is turned On, 12 volts is applied

and the retard function is activated. The retard will be removed when

the engine reaches about 600 rpm

and will not occur again until the

ignition is turned

Off. Connect the

supplied jumper from the Start-

Retard terminal to the IGN terminal

of the terminal strip (two terminals

up).

THREE STEP RPM LIMITS

The 7AL-3 has a built-in Three Step

Module Selector which allows you

to select up to three different rpm

limits. The activation terminals

are located on the bottom of the

third terminal strip and are listed

as Launch and Burnout. The third

rpm limit is the high rpm, which is

always active when there is an rpm

module installed in the "Race" holder

(except when the other rpm limits are

activated).

These modules can be used in a variety

of functions and are not limited to

launches and burnouts. Each of the two

optional rpm limits are activated when 12

volts is applied to their corresponding

terminals (Figure 10). The 12 volts can

come from switches, solenoids or relays

giving you a variety of ways to activate

the different rpm limits. The following

steps illustrate a general drag race

installation for use with a Burnout limit,

Launch limit and Race limit.

RAS

ON/OFF

RAS

ON/OFF

Figure 9 Wiring the Start Retard Function.

RAS

ON/OFF

Figure 10 Connecting the Three Step Module Selector.

7AL-3 SIDE VIEW

4500

RPM ACTIVATED

SWITCH

Figure 8 Side View of 7 AL-3

START RETARD PLUG-IN

DEGREE MODULE