Owners manual

INSTALLATION INSTRUCTIONS 7
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PROGRAMMING THE REV LIMIT
A tachometer is required to set the rev limit. The limit is programmed
by running the engine at half the desired rpm, then momentarily
grounding the Gray tach output wire from the MSD. A Gray jumper
wire is supplied to connect to the tach with another tee-splice
coming off to use for programming. A switch may also be installed
to ease adjustments of the limiter (Figure 12). The default rpm limit is
10,000 rpm and the limit is adjustable from 2,000 - over 10,000 rpm..
1. Start the engine and bring the rpm to half the desired rev limit
(for a 6,000 rpm limit, raise and hold the rpm to 3,000).
2. While holding the rpm steady, short the Gray tach wire to ground
for approximately one second. Note that the tach will go to zero
while grounded.
3. The tach will now display the programmed rev limit amount
for two seconds. If this value does not register on the tach, repeat the procedure and try a different
ground source.
The MSD Ready-to-Run Distributor has an optional built in Rev Limiter Verification feature. When activated,
it will display the rev limit setting at key-on. This feature is not activated from the factory. To enable this
feature, follow the procedure below.
Note: It is important to note that this feature should not be used with EFI systems. When activated, an rpm
signal is sent to the tachometer. With an aftermarket EFI system, this could activate the injectors
causing a flooding situation.
ENABLE REV LIMIT VERIFICATION
1. With the ignition switch in the off position, ground the Gray tach output wire.
2. With the Gray wire connected to ground, turn the ignition on without starting the engine.
3. Hold the Gray tach output wire to ground for seven seconds. (AT LEAST five seconds.)
4. Release the wire from ground before ten seconds have passed.
5. To confirm the process has worked, cycle turn the key On. The tachometer should sweep to the rpm
limit set on the ignition.
To deactivate the verification feature, repeat the process.
TO
TACH
OPTIONAL
PROGRAMMING
SWITCH
JUMPER GRAY
Figure 12 Setting the Rev Limiter.
VACUUM ADVANCE
Your distributor is equipped with an optional
vacuum advance canister. Vacuum advance
is generally used to improve cruising
economy and driveability, depending on
the application.
The chart in Figure 13 shows the relationship
between engine vacuum and the amount of
ignition timing advance.
To connect the vacuum advance, connect a
vacuum hose from the canister to a ported
vacuum source on the carburetor or throttle
body. Ported vaccum sources are located
above the throttle plates so there will not be
an excessive amount of timing advance at
idle and lower engine speeds.
0
2
4
6
8
10
12
14
12345678910111213141516
Inches of Vacuum
Degrees of Advance
OE Non Adjustable Vac. Adv. 1808
Figure 13 Vacuum Advance and Timing Chart.