Wed May 22, 2019 7:47 pm
I, Personally, don't like Champion plugs,- Having said that, their website should list a breakdown of their codes, the first group usually designates thread, reach and maybe electrode configuration, thenumber is usually heat- range ("softer" = hotter, for a cold-running engine or a bit of an oil-burner probably better in a rich-running engine with no mixture-weakening. A "hard, " plug is the converse, used for racing and arduous service where really hot electrodes could glow and cause pre-ignition (pinking) which can destroy a piston in seconds.
Suffix- letters usually indicate special features (RF shielding, inbuilt suppressor- resistor , ETC.
Until you have the code for a specific plug- manufacturer, you will not be able to make an informed choice, just because a particular plug works, doesn't mean it's the optimum.