FAQ: What do the numbers mean on my spark plug?

[pipebomb]

To most people, the numbers on their spark plug are a great mystery. Since a great many folk prefer to use the NGK brand, here's a link to a site that breaks down the puzzle of those mystifing symbols. Each manufacturer uses a different ordering system, but this should give anyone a good idea of what it means.

 

NGK- http://www.ngksparkplugs.com/techinfo/spar...rtnumberkey.pdf

 

*Updated*

Bosch- http://www.boschusa.com/popup_image.asp?im...esignationcodes

Champion- http://www.championsparkplugs.com/sparkplug411_champion.asp

 

 

*note: more links will be added for other manufacturers as they become avalible.