An incorrect heating value can lead to serious damage to the engine or, at best, operational disturbances. A spark plug converts high voltage from the engine's ignition system into a "spark" at the top of the cylinder. Spark plugs have different heating values, which are often indicated as rising or falling numbers stamped on the plug itself. As a rule, a rising numerical value indicates a colder spot.
1 - Good condition
2 - Saturated with oil due to a problem in the piston
3 - Must adjust the "gap" to the correct opening
4 - Evidence that the spark plugs have not been changed for a long time and must be changed immediately
5 - Saturated with lead due to high percentage of lead in fuel
6 - Saturated with coal due to poor combustion, the fuel pump and air filter must be checked
7 - As a result of the engine temperature rising above normal speed. Will check why
8 - Must change fuel type to higher octane number (98). Maybe also non-return valves
9 - Evidence of mechanical problem or foreign body in the combustion chamber