Three Labs Ensure Spark Plug Quality

When it comes to product quality control, Marshal has built a complete test and verification system supported by three professional laboratories: the Ceramic Physical and Chemical Laboratory, the Ceramic Insulator In-process Inspection Laboratory, and the Finished Product Function & Durability Laboratory. This testing framework covers the full manufacturing chain, conducting inspections starting from incoming raw materials, through semi-finished parts at each production stage, and extending all the way to final finished spark plugs. Every critical stage is placed under rigorous monitoring to identify potential defects at the earliest possible phase and prevent non-conforming items from moving to subsequent processes.

For product performance validation, the company strictly adheres to the international standard ISO 11565:2016. A total of 17 fundamental test items are implemented as mandatory routine checks. Beyond these baseline requirements, we carry out an additional four special test protocols specified by original equipment manufacturers. Our evaluation scope covers a wide range of critical technical indicators, including insulation performance, air tightness, heat rating, electrode durability, thermal shock resistance and more. Each parameter is assessed under controlled laboratory conditions to replicate real-world operating stress that spark plugs will encounter in service.

Thanks to this systematic laboratory setup and stringent testing protocols, production risks can be well managed and mitigated throughout mass production. Such robust quality assurance ensures consistent and reliable performance for every batch of spark plugs we ship. Whether serving aftermarket distributors or supporting OEM original equipment supply projects, our testing regime enables us to consistently deliver products that meet high-quality specifications and satisfy the demanding expectations of both replacement and OE markets.