Distributor Shim

The MSD IGNITION Distributor Shim (Part No. WAS10090) is a precision steel spacer designed to fine-tune distributor housing alignment in electronic and mechanical ignition systems. This 0.500-inch inner diameter, 1.000-inch outer diameter shim delivers the exact clearance control needed for optimal ignition timing and reliable engine performance across performance and stock applications.

MSD distributor shims are precision-engineered from hardened steel to maintain dimensional stability under heat and vibration. The 0.500-inch ID accommodates standard distributor shaft sizing, while the 1.000-inch OD seats against the distributor housing bore. At just 0.01 lbs with compact dimensions (1.85 x 0.15 x 4.15 inches), this shim installs quickly without requiring additional hardware or complex modification. Proper shimming ensures correct rotor-to-cap clearance, reducing misfires and maximizing spark delivery consistency.

Engine builders and tuners rely on distributor shims when dialing in ignition geometry during dyno testing, carburetor tuning, or aftermarket intake manifold installation. Misalignment between distributor housing and engine block can cause rotor offset, arcing, and performance loss. This shim corrects those issues without requiring distributor core swaps or block machining. It pairs seamlessly with MSD distributor housings and compatible ignition systems used in street performance, drag racing, and restoration builds where ignition reliability is non-negotiable.