MSD 85805 Installation

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

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in our monthly 8.5mm Super Conductor Spark Plug Wire give-away! Registering your product
will help if there is ever a warranty issue with your product and helps the MSD R&D team create
new products that you ask for! Go to www.msdperformance.com/registration.

Important:  Read these instructions before attempting the installation.

Note: An MSD Ignition is required with this Distributor.

Parts Included:

1 - Billet Distributor
  1 - Rotor
  1 - Distributor Cap

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

ing the battery cables, always remove the Negative (-) cable first and install it last.

1 - Advance Kit
1 - Tube of Gear Lubricant
1 - O-Ring

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.

M S D   •   W W W . M S D P E R F O R M A N C E . C O M   •   ( 9 1 5 )   8 5 7 - 5 2 0 0   •   F A X   ( 9 1 5 )   8 5 7 - 3 3 4 4

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.

FACTOR Advance Timing Retard Timing
For For

Cylinder Pressure  Low  High
Vacuum  High  Low
Energy of Ignition  Low  High
Fuel Octane  High  Low
Mixture (Air/Fuel)  Rich  Lean
Temperature  Cool  Hot
Combustion Chamber Shape  Open  Compact
Spark Plug Location  Offset  Center
Combustion Turbulence  Low  High
Load  Light  Heavy

        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.

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INSTALLATION INSTRUCTIONS 3

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  b e 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. 

SPRING COMBINATION RATE OF ADVANCE FIGURE 4

2- Heavy Silver  SLOWEST  A
1- Heavy Silver    B
1- Light Blue   
1-Heavy Silver    C
1-Light Silver   
2- Light Blue    D
1- Light Silver    E
1- Light Blue   
2- Light Silver  FASTEST  F

Figure 3 Spring Combination Chart. 

Figure 4 Advance Curves.

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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.

CHANGING THE ADVANCE STOP
BUSHINGS

1.  Remove the distributor cap and rotor.

2.  Remove the locknut and washer on  the bottom 
of the advance assembly (Figure 6).

3.  Remove    the  bushing  and  install  the  new  one. 
Install the washer and locknut.

BUSHING SIZE APPROXIMATE
CRANKSHAFT
DEGREES

Red-Smallest  28
Silver  25
Blue  21
Black-Largest  18

Figure 5 Advance Stop Bushing Chart.

LOCKING OUT THE CENTRIFUGAL
ADVANCE

1.  Remove the advance components including the 
springs, weights and the advance stop bushing 
from the advance assembly.

2.  Remove the roll-pin from the shaft retaining sleeve 
and slide the shaft up.

3.  Rotate the shaft 180° and insert the advance stop 
bushing pin into the small  hole on the  advance 
plate (Figure 7).

4.  Install the locknut and washer to the advance stop 
bushing pin. This locks the advance in place.

5.  Install the retaining sleeve and its roll-pin.

Figure 6 Changing the Advance Stop Bushing.

Figure 6  Locking Out the Centrifugal Advance.

Figure 7 Locking Out  the Advance.

M S D   •   W W W . M S D P E R F O R M A N C E . C O M   •   ( 9 1 5 )   8 5 7 - 5 2 0 0   •   F A X   ( 9 1 5 )   8 5 7 - 3 3 4 4

INSTALLATION INSTRUCTIONS 5

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.  Loosen the distributor hold down clamp and 
slide the clamp out of the way.

6.  Lift the distributor out of the engine.  Note that 
the rotor rotates as you lift the distributor out. 
This is due to the helical cut gear and should 
be taken into consideration when installing the 
new distributor.

7.  Install  the  new  O-ring and apply  a  liberal 
amount of the supplied lubricant to the distributor gear.

8.  Install the distributor making  sure that the rotor comes to rest pointing at the fixed mark. If the 
distributor will not fully seat with  the rotor pointing to the  marked position, you may need to 
rotate the oil pump shaft until the rotor lines up and the distributor fully seats.

9.  Position and tighten the hold down clamp onto the distributor.  

10. Install the distributor cap and spark plug wires one at a time to ensure correct location. 

Figure 8 Marking the Rotor Location.

M S D   •   W W W . M S D P E R F O R M A N C E . C O M   •   ( 9 1 5 )   8 5 7 - 5 2 0 0   •   F A X   ( 9 1 5 )   8 5 7 - 3 3 4 4

6 INSTALLATION INSTRUCTIONS

GREEN

PN 8860

HARNESS

VIOLET

GREEN

VIOLET

FROM

IGNITION KEY

(ORIGINAL COIL WIRE)

IGNITION

KEY

RED

WHITE (NOT USED)

TO 12V

ORANGE

BLACK

+

T
A
C
H

C+

C-

IGN

PTS

M+

M-

GROUND

RPM

7200

HEAVY BLACK

HEAVY RED

+

TO BATTERY

TO BATTERY

+

PRO POWER COIL

TO 12V

GREEN

PN 8860 HARNESS

VIOLET

+

TO BATTERY

TO BATTERY

+

+

Multiple

Spark

Discharge

PART NO.

AUTOTRONIC CONTROLS CORPORATION

SERIAL NO..

IGNITION

®

WARNING: High voltage is present on the coil terminals. Do not touch the terminals or 

coil tower when the engine is cranking or running. 

TACH

OUTPUT

IGNITION KEY

FROM

IGNITION KEY

(ORIGINAL COIL WIRE)

HEAVY RED

HEAVY BLACK

RED

WHITE (NOT USED)

ORANGE

BLACK

        Figure 9 Wiring to an MSD 6-Series Ignition Control.

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        Figure 10 Wiring to an MSD 7-Series Ignition Control.

INSTALLATION INSTRUCTIONS 7

T
A
C
H

C+

C-

IGN

PTS

M+

M-

HEAVY RED

TO GROUND

NOT USED

WHITE

WHITE

TIMING

CONTROL

SWITCHED 12 VOLTS
FROM IGNITION KEY

YELLOW

RED

RED

BLACK

NOT

USED

ORANGE

HEAVY BLACK

+

GREEN

VIOLET

+

TO BATTERY

TO BATTERY

THRUST COLLAR

Note: MS D  6  and  7  Series  Ignitions 

share the same color wiring.

        Figure 11 Wiring with an MSD 7-Series Ignition and Timing Control.

REPLACING THE DISTRIBUTOR GEAR

To replace the distributor gear on the MSD Distributors, the following steps must be followed.

1.  Remove the original spiral pin with a punch and press the original gear off the shaft. Press the new 

gear onto the shaft and line up the holes for the spiral pin. Note: The holes may not line up.

2.  If the holes line up, measure the distance as shown in the diagram. If the measurement is not correct 
or the holes do not line up, a new hole must be drilled. If the measurement is within specifications 
and the holes line up, install a new spiral pin.

3.  To drill a new hole, turn the gear on the shaft so the gear hole is approximately 90° to the original 
shaft hole. Carefully position the gear on the shaft to match the specifications given in the drawing. 
Note: Before measuring, push the shaft in to remove all of the end play.

4.  When the gear is in the correct position, drill a 0.125” hole through the distributor shaft. Install a 
new spiral pin and recheck the measurement.

Note: If the measurement is not within specifications after drilling, a slight correction can be made by 

machining the upper face of the thrust collar. Do not remove more than 0.010” or rotor-to-cap 
interference may result.

4.005” MAX.

3.996” MIN.

        Figure 12 Replacing the Distributor Gear.

PRESS FIRMLY TO
TAKE OUT ALL END
PLAY BEFORE
MEASURING.

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Tech Notes

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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.

All returns must have a Return Material Authorization (RMA) number issued to them  before 

being returned. To obtain an  RMA  number please contact MSD Customer Service  at 1 (888) MSD-7859 or visit 
our website at www.msdperformance.com/rma to  automatically obtain  a  number  and  shipping information.

When returning the unit for repair, leave all wires at the length in which you have them installed. Be sure to include 
a detailed account of any problems experienced, and what components and accessories are installed on the vehicle. 
The repaired unit will be returned as soon as possible using Ground shipping methods (ground shipping is covered 
by warranty). For more information, call MSD at [phone]. MSD technicians are available from 7:00 a.m. to 
5:00 p.m. Monday - Friday (mountain time).

Limited Warranty

  M

SD warrants this product to be free from defects in material and workmanship under its intended normal use*, 
when properly installed and purchased from an authorized MSD dealer, for a period of one year from the date of 
the original purchase. This warranty is void for any products purchased through auction websites. If found to be 
defective as mentioned above, it will be repaired or replaced at the option of MSD. Any item that is covered under 
this warranty will be returned free of charge using Ground shipping methods. 
  This shall constitute the  sole remedy of the purchaser and the sole liability of MSD. To the extent permitted by 
law, the foregoing is exclusive and in lieu of all other warranties or representation whether expressed or implied, 
including any implied warranty of merchantability or fitness. In no event shall MSD or its suppliers be liable for special 
or consequential damages.
  *Intended normal use means that this item is being used as was originally intended and for the original application 
as sold by MSD. Any modifications to this item or if it is used on an application other than what MSD markets the 
product, the warranty will be void. It is the sole responsibility of the customer to determine that this item will work for 
the application they are intending. MSD will accept no liability for custom applications.

M S D   •   W W W . M S D P E R F O R M A N C E . C O M   •   ( 9 1 5 )   8 5 7 - 5 2 0 0   •   F A X   ( 9 1 5 )   8 5 7 - 3 3 4 4

© 2012 Autotr onic Contr ols Corporation

FRM29111          Revised 12/11        Printed in U.S.A.