- 1 - MSD Ignition
- 1 - Harness, PN 8860
- 1 - Mag Pickup
- 1 - Main Harness
- 1 - Parts Bag
- 4 - Vibration Mounts
- 1 - Sc rew d river
WARNING: During installation, disconnect the battery cables. When disconnecting the battery always remove the Negative cable first and install it last.
Note: The Carb label supplied is required to aid in passing the California Smog Check program. This label must be installed in an underhood location that is readily visible.
Note: If you're triggering an aftermarket EFI system with the Gray wire of the MSD, see page 4 to deactivate the tach verification feature.
OPERATION AND FEATURES
The Digital 6A and 6AL use a high speed RISC microcontroller to control the ignition's output while constantly analyzing the various inputs such as supply voltage, trigger signals and rpm. The high speed controller can make extremely quick compensations to the output voltage, multiple spark series, timing and rpm limits while maintaining precise timing and accurate rev limiting. The circuits and controller of the MSD have been thoroughly filtered to create protection against Electro Magnetic Interference (EMI).
The Digital 6A and 6AL feature a capacitive discharge ignition design. The majority of stock ignition systems are inductive ignitions. In an inductive ignition, the coil must store and step up the voltage to maximum strength in between each firing. At higher rpm, since there is less time to charge the coil to full capacity, the voltage falls short of reaching maximum energy which results in a loss of power or top end miss.
The MSD Ignition features a capacitor which is quickly charged with 520 - 535 volts and stores it until the ignition is triggered. With the CD design, the voltage sent to the coil positive terminal is always at full power even at high rpm.
The MSD produces full power multiple sparks for each firing of a plug. The number of multiple sparks that occur decreases as rpm increases, however the spark series always lasts for 20° of crankshaft rotation. Above 3,000 rpm there is simply not enough “time” to fire the spark plug more than once, so there is only one powerful spark.
The Digital 6A and 6AL have a built in reverse polarity protection circuit. This will protect the ignition in the event of wrong connections.
There is an LED that monitors the status of the Ignition. When the key is turned On, without starting the engine, the LED will momentarily turn on and then turn off. When running, the LED will flash with each trigger signal which will make it appear to be on steady as rpm increases.
Note: Solid Core spark plug wires cannot be used with an MSD Ignition.
Note: Do not use digital or dial back timing lights.
The Digital 6AL features a built-in Soft Touch Rev Control that provides a smooth and accurate rev limit by dropping the spark to individual cylinders. The Soft Touch produces a load-free rev limit that is within 1% of the selected rpm.The rpm limit is adjusted in 100 rpm increments with the sealed rotary switches under the black cover on top of the 6AL.
The MSD is programmed at the factory for use on 8-cylinder engines. If you are installing it to a different engine you will have to program the Ignition. This is easily achieved through the cylinder select wire loops on the side of the ignition. Page 5 outlines setting the cylinder select.
The Digital 6A and 6AL will operate on any negative ground, 12 volt electrical system with a distributor. The MSD can be used with 16 volt batteries and can withstand a momentary 24 volts in case of jump starts. The Ignition will deliver full voltage with a supply of 9 - 18 volts. If your application does not use an alternator, allow at least 15 amp/hour for every half hour of operation. The MSD uses about .9 Amps for every 1,000 rpm. If the engine is cranked with the same battery or other accessories such as an electric fuel or water pump are used, the amp/hour rating should be higher.
The Digital 6A and 6AL Ignition can be used with most stock coils and aftermarket coils designed to replace the stock coils. The line of MSD Blaster Coils are great for street and mild racing. For extended high rpm operation the Blaster HVC, PN 8252 or HVC II, PN 8253, are recommended. For more information on recommended coils, check with our Customer Service Department at (915) 855-7123.
The MSD Ignition features a Gray Tach Output wire that provides a trigger signal for tachometers, a shift light or other add-on rpm activated devices. The Tach Output wire produces a 12 volt square wave signal with a 22.5° duty cycle.
Some vehicles with factory tachometers may require a Tach Adapter to operate with the MSD. For more information on Tachometers and MSD Tach Adapters, see the Tachometer Section on page 6. If your GM vehicle has an in-line filter it may cause the tach to drop to zero on acceleration. If this occurs, bypass the filter.
SPARK PLUGS AND WIRES
Spark plug wires are very important to the operation of your ignition system. A good quality, helically wound wire and proper routing are required to get the best performance from your ignition, such as the MSD 8.5mm Super Conductor Wire. Helically wound wires provide a good path for the spark to follow while keeping Electro Magnetic Interference (EMI) to a minimum. Excessive EMI, such as the amount that solid core wires produce, will interfere with the operation of the MSD. Solid Core spark plug wires cannot be used with an MSD Ignition.
Routing: Correct routing of the plug wires is also important to performance. Wires should be routed away from sharp edges and engine heat sources. If there are two wires that are next to each other in the engine’s firing order, the wires should be routed away from each other to avoid inducing a spark into the other wire. For example, in a Chevy V8, the firing order is 1-8-4-3-6-5-7-2. The #5 and #7 cylinders are next to each other in the engine and in the firing order. If the voltage from the #5 wire is induced into #7 detonation could occur and cause engine damage. To add more heat protection to your plug wires, MSD offers Pro-Heat Guard, PN 3411. This is a glass woven and silicone coated protective sleeve that you slide over your plug wires. For extra protection of the spark plug boots, MSD offers Pro Boot Guard, PN 3412.
Spark Plugs: Choosing the correct spark plug design and heat range is important when trying to get the best performance possible. Since there are so many engine combinations and manufacturers, MSD does not recommend which plug or gap is exactly right for your application. It is recommended to follow the engine builder or manufacturer’s specification for spark plugs. With that, you can then experiment with the plug gap to obtain the best performance. The gap of the plugs can be opened in 0.005" increments, then tested until the best performance is obtained. MSD judges the plug gap by compression and components.
These examples are just starting points to get you going in the right direction. Every application is different and should be tested and tuned.