Spark Plug Thread Adaptors 18mm down to 14mm Brass (M14 & M18)

The Spark Plug Thread Adaptors 18mm down to 14mm in brass deliver a reliable bridge between different plug sizes for versatile ignition systems. Designed to suit long-reach 14mm plugs, the adaptor’s seated shoulder lifts the plug slightly from the chamber, enabling a clean seal and improved clearance in tight spaces. Available for M14 with 1.25mm pitch and M18 with 1.5mm pitch, these adaptors ensure precise threading and secure fitment across a range of engines. Brass construction provides good electrical conductivity and corrosion resistance, while the compact profile enhances compatibility with limited service bays. Ideal for workshops and DIY enthusiasts seeking a durable, dependable solution to swap spark plug sizes without changing entire assemblies.