MSD Ignition 8485 Installation Instructions And Operators Manual

Important:
Contents

Timing Functions

Choosing an Advance Curve

Setting or Locking Out the Centrifugal Advance
Installing the Distributor
Wiring the Distributor

Parts Included In This Kit

1 Billet Distributor
2 #10 Disc Washers
3 Advance Stops
1 Retaining Nut
7 Shims
1 Clamp Stud
4 Advance Springs
1 Hold Down Bracket
2 O-Rings
TIMING FUNCTIONS
Before continuing with the installation, here are a few definitions you should be
aware of:
Initial Timing: This is the base timing of the engine before centrifugal advance
begins.
Centrifugal Advance: The centrifugal advance mechanism is made up of weights,
springs, advance cam, and an advance stop bushing. The amount and rate of
advance that your distributor is capable of is determined by the centrifugal timing.
If you ever wish to lock out the centrifugal advance, refer to the centrifugal advance
section.
Total Timing: This is the total of the initial timing plus the centrifugal advance added
together. Example: 10° Initial + 25° centrifugal = 35° Total Timing.
CHOOSING AN ADVANCE CURVE
The function of the advance curve is to match the ignition timing to the burning rate
of the fuel and speed (rpm) of the engine. Any factor that changes the burning rate
of the fuel or the engine speed can cause a need for an ignition timing change.
Figure 1 shows some of the factors that will affect engine timing.
AUTOTRONIC CONTROLS CORPORATION
Installation Instructions
MSD Billet VW Distributor
PN 8485
Read these Instructions before attempting the installation.
• 1490 HENRY BRENNAN DR., EL PASO, TEXAS 79936 • (915) 857-5200 • FAX (915) 857-3344