Spark Plug Compatibility Finder
Compare a candidate spark plug with exact engine requirements for thread, reach, heat range, electrode type, gap and manufacturer reference information.
Check spark plug fitment
How spark plug compatibility works
Spark plug fitment depends on exact engine requirements. Thread size and reach are mechanical constraints, while heat range, electrode construction and gap are application-specific.
Thread and reach
A plug with the wrong thread or reach can be mechanically unsuitable.
Heat range
Heat-range numbering is manufacturer-specific and should not be compared across brands as if universal.
Gap
Use the specified engine and spark-plug manufacturer gap rather than a generic setting.
Installation
Use the exact installation procedure and manufacturer instructions.
FAQs
Can I choose by thread size alone?
No. Reach, heat range, electrode design and gap also matter.
Are heat-range numbers universal?
No. Manufacturer numbering systems differ.