Spark Plug Index Shims 14mm Small O.D.

Spark Plug Index Shims 14mm Small O.D. by ALLSTAR PERFORMANCE are precision spacers engineered to solve ignition timing and spark plug seating challenges in high-performance engine builds. As a mechanic working with modified and racing engines, you know that even slight variations in spark plug depth can affect combustion chamber geometry and ignition characteristics. These shims allow you to fine-tune spark plug positioning without requiring costly head modifications or different plug styles, making them essential for custom engine development, vintage restorations, and competitive motorsports applications where every detail impacts performance.

The 14mm small O.D. design provides a compact footprint that fits standard spark plug thread wells while offering controlled depth adjustment. These aluminum shims are designed to stack or use individually, depending on your specific ignition timing requirements and combustion chamber layout. The small outer diameter ensures clearance inside the plug hole without interference, while the precision engineering maintains proper sealing and prevents gas leakage around the spark plug. Weighing just 0.03 lbs per shim, they add minimal mass to your engine while delivering maximum adjustability for fine-tuning your ignition system to match custom displacement, compression ratios, or modified cylinder head designs.

Professionals and serious enthusiasts benefit most from these shims when building custom engines, upgrading to higher compression ratios, or transitioning between different spark plug brands with varying seat depths. Installation is straightforward—simply place the shim onto the threaded spark plug hole before installing your plug, allowing you to achieve the exact plug positioning your engine demands. Compatibility spans most modern automotive engines using standard spark plug threads, though verification with your specific engine specs and cylinder head design is recommended before installation. ALLSTAR PERFORMANCE's reputation for precision engineering ensures these shims maintain consistent dimensions across multiple pieces, critical for balancing ignition performance across all cylinders in your build.