MSD 84211 Rotor Phasing Kit for MSD Distributors SKU: 6609

MSD Rotor Phasing Kit for MSD Distributors | 84211

Get your EFI timing dialed in with precision!

When adding EFI to your engine, you’ll often need to advance your ignition timing to give your ECU the control it needs. But advancing the timing can cause rotor phasing issues inside your distributor — leading to poor spark alignment, reduced performance, and misfires.

The MSD Rotor Phasing Kit solves this problem by allowing you to fine-tune the alignment of your distributor rotor relative to the distributor cap terminals. By adjusting the rotor position, you ensure the spark is delivered exactly when and where it’s needed, keeping your ignition system firing on point.

Perfect for EFI conversions, high-performance builds, and anyone looking to maximize ignition precision!

This Rotor Phasing Kit is for use with MSD Distributor #8437 or MSD Caps #8431, 84333 & 84313.

What is Rotor Phasing & Why Does It Matter?

Rotor phasing refers to the alignment between the rotor and the cap terminals inside your distributor. Ideally, when the ignition coil fires, the rotor is perfectly lined up with the correct terminal to send spark energy to the corresponding cylinder.

When you advance your ignition timing (which is common in EFI setups because the ECU needs to "see" more initial timing to take proper control), it shifts when the spark is delivered — but the rotor stays in its mechanical position. This can cause the rotor to be misaligned with the cap terminal at the moment of spark, leading to:

• Weak or scattered spark

• Crossfire between terminals

• Misfires under load

• Loss of power and efficiency

The MSD Rotor Phasing Kit lets you adjust the rotor position so it stays properly phased with the cap terminals, even after advancing your timing for EFI. This ensures clean, reliable spark delivery throughout the RPM range.

Why EFI Requires Advanced Timing

Most aftermarket EFI systems require the ignition timing to be advanced because they rely on the crank signal to manage ignition events. By advancing the base timing, you allow the ECU to "retard" or "advance" timing dynamically based on engine load, RPM, and other inputs. Without advancing the timing mechanically, the ECU wouldn’t have the adjustment range it needs for optimal performance and driveability.

Kit Features

• Adjustable rotor design for precise phasing

• Ideal for EFI conversions or high-performance tuning

• Prevents misfires, crossfire, and weak spark issues

• Improves spark alignment for better performance and reliability

• Compatible with MSD Distributor #8437

Correct your spark with MSD’s Rotor Phasing Kit! Prevent misfires and align your spark perfectly for EFI conversions and advanced timing setups.