MSD Ford Billet Distributors
PN 8473: 2.3L, PN 8580: 351C, 351M, 400, 429, 460
PN 8582: 289, 302, PN 8584: 351W
PN 85805: 351W w/Edelbrock Victor Jr. Intake
Important: Read these instructions before attempting the installation.
Note:An MSD Ignition is required with this Distributor.
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Parts Included: |
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1 |
- Billet Distributor |
1 - Advance Kit |
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1 |
- Rotor |
1 |
- Tube of Gear Lubricant |
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1 |
- Distributor Cap |
1 |
- O-Ring |
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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.
Note:These distributors must be used with an MSD Ignition Control.
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.
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.
MSD IGNITION • www . msdignition . com • (915) 857 - 5200 • FAX (915) 857 - 3344
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INSTALLATION INSTRUCTIONS |
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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.
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FACTOR |
Advance Timing |
Retard Timing |
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For |
For |
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Cylinder Pressure |
Low |
High |
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Vacuum |
High |
Low |
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Energy of Ignition |
Low |
High |
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Fuel Octane |
High |
Low |
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Mixture (Air/Fuel) |
Rich |
Lean |
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Temperature |
Cool |
Hot |
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Combustion Chamber Shape |
Open |
Compact |
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Spark Plug Location |
Offset |
Center |
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Combustion Turbulence |
Low |
High |
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Load |
Light |
Heavy |
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Figure 1 Ignition Timing Factors.
As you can see from the chart, most factors will change throughout the range of the engine operation. The timing mechanism of the distributor must make timing changes based on these factors.
Example: An engine has 11:1 compression with a high energy ignition. With the specifications given, you will have to retard the timing for the high compression and high energy ignition. By comparing the engine’s specifications against the chart, a usable timing guideline can be found. Engines with a combination of items from both columns will require a timing that is set in the mid range.
Obviously a full technical explanation of correct ignition timing would be very complicated. The best way to arrive at a suitable ignition curve for your engine is to use the Ignition Timing Factors Chart as a guide and compare it to the Advance Graphs in Figure 4 until a suitable curve is found. When selecting your advance curve, use detonation (engine ping) as an indicator of too much advance, and a decrease in power as an indicator of too little advance.
Tips on Selecting an Advance Curve
•Use as much initial advance as possible without encountering excessive starter load.
•Start the centrifugal advance just above the idle rpm.
•The starting point of the centrifugal advance curve is controlled by the installed length and tension of the spring.
•How quickly the centrifugal advance (slope) comes in is controlled by the spring stiffness. The stiffer the spring, the slower the advance curve.
•The amount of advance is controlled by the advance bushing. The bigger the bushing, the smaller the amount of advance.
MSD IGNITION • www . msdignition . com • (915) 857 - 5200 • FAX (915) 857 - 3344
INSTALLATION INSTRUCTIONS |
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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. Refer to the Spring Combination Chart (Figure 3) for combinations that can be achieved.
To change the springs, remove the cap and rotor and use needlenose pliers to remove the springs. Be sure the new springs seat in the
groove on the pin.
Timing Curve From Factory
Figure 2 The Factory Equipped Curve.
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SPRING COMBINATION |
RATE OF ADVANCE |
FIGURE 4 |
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2- Heavy Silver |
SLOWEST |
A |
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1- Heavy Silver |
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B |
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1- Light Blue |
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1-Heavy Silver |
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C |
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1-Light Silver |
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2- Light Blue |
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D |
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1- Light Silver |
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E |
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1- Light Blue |
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2- Light Silver |
FASTEST |
F |
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Figure 3 Spring Combination Chart.
Figure 4 Advance Curves.
MSD IGNITION • www . msdignition . com • (915) 857 - 5200 • FAX (915) 857 - 3344
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