Thanks to the copper (CU), and especially the silver central electrode, the thermal conductivity and therefore the heat resistance are increased. The advantages of spark plugs with platinum central electrodes are easier spark formation, as well as less wear and a wide temperature range.
The glow number recommended by the manufacturer may be deviated from only in cases where operating conditions differ significantly from normal and malfunctions occur. If the spark plugs are constantly covered with soot, i.e. they do not reach their self-cleaning temperature (when traveling short distances), then it is recommended to replace them with spark plugs with the next higher heat rating. If the engine is operated exclusively at full throttle, then it is recommended to replace the spark plugs with spark plugs with the next lower heat rating.