MSD 8680 Adjustable Timing Control Installation - Manual (Page 2)

2 INSTALLATION INSTRUCTIONS
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Figure 3 How to use the Supplied Wire Splice Device.
WIRING
Figure 4 Installing the Weathertight Connector.
Operating the Control
After installation, it is recommended to check the timing. Before starting the vehicle, turn the Control Knob
to the full 15° mark. This is the stock timing setting. As the Knob is turned counterclockwise, the timing
retards. As detonation occurs, slowy retard the timing until the “pinging” noise is not audible. Adjust the
timing as driving conditions change.
Resetting the Timing
It is possible to set the Timing Control up to where you can retard and advance the timing 7.5° each.
To do this, position the Control Knob in the center (approximately 7.5°) then reset the timing to factory
specifications.
WIRE FUNCTIONS
Yellow This is the trigger output wire. It connects to the White wire of an MSD 6 Series Ignition or
“Points” terminal of a 7 Series Ignition.
Red This wire is responsible for turning the Timing Control on and off. It connects to switched
12 volt source. It can be spliced into the small red wire of the MSD.
Black This is the ground wire and must be connected to a good engine or chassis ground.
TRIGGER WIRES
Violet These wires connect to the magnetic pickup of the distributor or crank trigger. The
Green Violet is positive (+) and the Green wire is negative (-). When this connector is used
the White wire is not.
White This is the trigger input wire for breaker points or ignition amplifier. When this wire is used,
the magnetic pickup wires (violet and green) are not.
Control Knob
The Black and Gray wires with the 2-Pin Weathertight connector are the Control Knob wires. After the
Timing Control is mounted, the Harness should be routed to the unit. The Control Knob should be
mounted within easy reach of the driver. Before mounting the Control Knob, make sure the wiring harness
reaches the unit.
If the harness must be routed through the firewall, drill a 3/8" hole and use the supplied grommet to route
the wires through. Install the supplied 2-Pin Weathertight connector to the wires after all of the routing is
finished (Figure 4). The position of the wires in the connector is not important.