Installation Manual

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MSD Pro-Billet Chevrolet V8

Tach Drive Distributor

PN 8571

with Vacuum Advance, PN 8572

Important: Read these instructions before attempting the installation.

Note: An MSD Ignition is required with this Distributor.

Parts Included:

1 - Pro-Billet Distributor

1 - Rotor, PN 8467

1 - Distributor Cap, PN 8433

1 - Wire Retainer

2 - 1.5" Self Tapping Screws

2 - 10-32 x 3/4" Socket Head Screws

Note: The cap of this Distributor requires spark plug style terminals. You may need to change the

terminals and boots of your wires. MSD offers two kits, PN 8849 or PN 8848 that are supplied

with nine boots and terminals. A socket style cap is available as PN 8437.

Note: If the gear is ever replaced, MSD Gear (PN 8531) is required for replacement due to the

.500" diameter shaft.

TIMING FUNCTIONS

Before continuing with the installation, here are a few deﬁnitions you should be aware of:

Initial Timing: This is the base timing (also referred to as idle timing) of the engine before the

centrifugal advance begins.

Centrifugal Advance: The centrifugal (or mechanical) advance mechanism is made up of weights,

springs, advance cams, 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 (When checking Total timing, disconnect

the vacuum canister and plug the vacuum source).

Vacuum Advance (PN 8572 Only): The vacuum advance will advance the timing up to 10° during

partial throttle driving (with 15 lbs. of vacuum). The vacuum line should be routed to a ported

vacuum outlet above the throttle plates.

Note: MSD Distributors are supplied with the heavy (slow) advance springs installed. This is to

prevent detonation in certain applications. Review the information on pages 2-4 to determine

the best advance curve for your application.

1 - Advance Kit

1 - Gasket

1 - Tube of Gear Lubricant

2 - O-Rings

1 - Vacuum Advance Lock-Out Kit

(PN 8572 Only)

1 - Gear Drive Adapter

WARNING: Before installing the MSD Distributor, disconnect the battery cables. When

disconnecting the battery cables, always remove the Negative (-) cable ﬁrst

and install it last.

M S D I G N I T I O N • www . ms d ig n i t i o n . c o m • (9 1 5 ) 85 7 - 5 2 0 0 • FA X ( 9 1 5 ) 8 5 7 - 3 3 4 4

Summary of content (8 pages)

PAGE 1
MSD Pro-Billet Chevrolet V8 Tach Drive Distributor PN 8571 with Vacuum Advance, PN 8572 Important: Read these instructions before attempting the installation. Note: An MSD Ignition is required with this Distributor. Parts Included: 1 - Pro-Billet Distributor 1 - Rotor, PN 8467 1 - Distributor Cap, PN 8433 1 - Wire Retainer 2 - 1.
PAGE 2
INSTALLATION INSTRUCTIONS 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.
PAGE 3
INSTALLATION INSTRUCTIONS CENTRIFUGAL ADVANCE CURVE Selecting the Advance Springs The rate, or how quick the advance comes in is determined by the type of springs which are installed on the distributor. The MSD distributors are equipped with two Heavy Silver springs installed. These will give you the slowest advance curve possible (Figure 2). The parts kit contains two additional sets of springs which can be used to match the advance curve to your particular application.
PAGE 4
INSTALLATION INSTRUCTIONS Selecting the Advance Stop Bushing Three different advance stop bushings are supplied in the distributor kit. The distributor comes with a Blue (21°) bushing already installed. If a different amount of centrifugal advance is desired, follow the next procedure to change the bushings. The chart in Figure 5 gives the size and approximate degrees for the corresponding bushings.
PAGE 5
INSTALLATION INSTRUCTIONS INSTALLING THE DISTRIBUTOR 1. Remove the existing distributor cap without disconnecting any of the spark plug wires. 2. With the cap off, crank the engine until the rotor is aimed at a fixed point on the engine or firewall. Note this position by making a mark (Figure 8). 3. Place the distributor cap back on and note which plug wire the rotor is pointing to. MARK THE SPARK PLUG WIRES and remove the distributor cap. 4. Disconnect the wiring from the distributor. 5.
PAGE 6
INSTALLATION INSTRUCTIONS Mechanical drive When using a stock GM mechanical drive tach the supplied square tach drive adapter must be used. The gear drive comes pre-lubed from the factory. When lubricating the tach cable, it is recommended to lube the gear set. The backlash is set at the factory, however it can be adjusted. VACUUM ADVANCE LOCKOUT If you do not want to use the vacuum advance canister of the PN 8572, MSD has supplied a lockout mechanism. 1.
PAGE 7
INSTALLATION INSTRUCTIONS WARNING: High voltage is present on the coil terminals. Do not touch the terminals or coil tower when the engine is cranking or running. Figure 13 Wiring to an MSD 6-Series Ignition Control. Figure 14 Wiring to an MSD 7-Series Ignition Control. MSD IGNITION • w w w . m s d i g n i t i o n .
PAGE 8
Note: MSD 6 and 7 Series Ignitions share the same color wiring. Figure 15 Wiring with an MSD 7-Series Ignition and Timing Control. Service In case of malfunction, this MSD component will be repaired free of charge according to the terms of the warranty. When returning MSD components for warranty service, Proof of Purchase must be supplied for verification. After the warranty period has expired, repair service is based on a minimum and maximum fee.