The MSD 6A and 6AL ignition controls are digital ignition systems utilizing a RISC microcontroller for precise timing and control. These systems are designed for automotive applications and feature capacitive discharge ignition technology. Installation requires disconnecting the battery, with the negative cable removed first, and includes components such as the ignition unit itself and a wiring harness (PN 8860). The 6AL model additionally includes vibration mounts and a screwdriver. The documentation stresses the importance of resetting the engine timing after installation.
Parts Included
The MSD Digital 6A (PN 6201/62013) and 6AL (PN 6425/64253) each include the following components:
- One MSD Ignition unit
- One Harness, PN 8860
Additionally, the 6AL model includes:
- Four Vibration Mounts
- One Screwdriver
Installation Precautions
Prior to installation, it is crucial to disconnect the battery cables to prevent electrical hazards. The documentation explicitly states that the negative cable should be removed first and installed last. A “Carb label” is supplied with the unit and is required for passing the California Smog Check program; this label must be installed in a readily visible underhood location.
Digital Operation and Features
The MSD 6A and 6AL utilize a high-speed RISC microcontroller to manage ignition output. This controller continuously monitors inputs such as supply voltage, trigger signals, and engine RPM. The system dynamically adjusts output voltage, multiple spark series, timing, and RPM limits to maintain accurate rev limiting and precise timing. The circuits and controller are filtered to minimize Electro Magnetic Interference (EMI).
Capacitive Discharge Ignition Explained
The Digital 6A and 6AL employ a capacitive discharge ignition design, differing from the inductive ignition systems found in many stock vehicles. In an inductive ignition, the ignition coil both stores and steps up voltage. Capacitive discharge systems utilize a separate capacitor to store energy, allowing for faster discharge and potentially higher spark energy. The documentation does not provide specific details regarding the advantages or disadvantages of this approach.
Protection Features
The Digital 6A and 6AL incorporate a built-in reverse polarity protection circuit. This feature safeguards the ignition system against damage resulting from incorrect wiring connections.
Triggering Aftermarket EFI Systems
If the MSD ignition is being used to trigger an aftermarket EFI (Electronic Fuel Injection) system via the gray wire, the documentation instructs users to deactivate the tach verification feature. Specific instructions for deactivating this feature can be found on page 5 of the installation instructions (as referenced in Source [1]).
Timing Considerations
The documentation emphasizes that installing a Digital Series Ignition will affect engine timing. Therefore, it is essential to reset the engine timing to the manufacturer’s specifications after installation. Failure to do so may result in suboptimal engine performance or damage.
Online Product Registration
MSD encourages users to register their products online at www.msdperformance.com/registration. Registration aids in warranty claims and provides MSD’s R&D team with valuable data for future product development.
Conclusion
The MSD 6A and 6AL ignition controls represent a digital upgrade to traditional ignition systems, offering precise timing control and protection features. Proper installation, including battery disconnection and timing adjustment, is critical for optimal performance. The inclusion of a reverse polarity protection circuit enhances system reliability. Users should consult the full installation instructions for detailed guidance and specific configuration options, particularly when integrating with aftermarket EFI systems.