Spark plug identification chart. . Sep 11, 2025 · Explore the complete spark plug size chart with thread diameters, reaches, and socket sizes. Find the right spark plug for cars, bikes, and small engines. View full size version of NGK spark plug numbering chart. Apr 29, 2016 · Here's a handy visual guide that shows how the appearance of your spark plugs can help you diagnose engine & ignition problems. View full size version of NGK premium plug numbering chart. Want to diagnose engine issues fast? Learn how to read spark plugs, identify rich or lean conditions, spot oil burning, and use a spark plug color chart for easy analysis. Find out what normal, carbon, oil, wet, burned and worn spark plugs look like and how to replace them. We break down how to decode the part number and stock number on your NGK spark plugs. NGK lists a design symbols chart in the front of every spark plug catalog. View full size version of NGK performance plug numbering chart. Learn how to examine your spark plugs for signs of damage, fouling or performance problems. Wondering what the numbers and letters on an NGK spark plug mean? These NGK spark plug charts explain how NGK's numbering system works. Learn how to identify AC Delco spark plugs by prefix, suffix, number and heat range. See examples of different types of spark plugs and their applications. yqfd gazx zky leewth uaqql eysr kpzq fzbg hsmzrde vkwtq