8360 Datasheet, PDF (7/8 Pages) Mallory performance club – MSD Pro-Billet Ready-to-Run Distributor

INSTALLATION INSTRUCTIONS
7
TACHOMETER INFORMATION
The MSD Ready-to-Run has a Gray wire that provides a 12 volt square
wave, 20° duty cycle tachometer signal that will trigger most tachometers.
It is recommended to connect this lead to your tach’s trigger input wire
and check its operation. Note that the rpm limiter is extremely accurate
and due to the variety of tachometers available, there may be differences
in the displayed rpm.
OPTIONAL
PROGRAMMING
SWITCH
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..
TO
TACH ^JUMPER
GRAY
Figure 12 Setting the Rev Limiter.
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.
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.
OE Non Adjustable Vac. Adv. 1808
14
12
10
8
6
4
2
0
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16
Degrees of Advance
Figure 13 Vacuum Advance and Timing Chart.
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