How the correct selection and maintenance of spark plugs

Usually spark plug life of 15000km, long-lasting spark plug life of 30000km. Engine work, the temperature of the spark plug insulator skirt should be maintained at 500 to 600 ℃. If the temperature is too low, the insulator is easy to coke deposition may cause leakage misfire phenomenon; if the temperature is too high, could easily cause preignition and knock.Spark plug failure phenomenon common in use are as follows:(A), the spark plug serious ablation. Scars, damage from the spark plug top electrode melting, ablation are that the spark plug has been destroyed, and should be replaced. Replacement should check ablation disease as well as a change in color, in order to analyze the causes of the failure.(1) Electrode melted and insulator was white. Show that the combustion chamber temperature is too high. This may be caused by overheating of the exhaust valve combustion chamber too much coke, the valve clearance is too small or the cooling device is bad, it may spark plug is not tightened as specified.
(2) electrode round, and insulator knot and a scar on. Indicative of engine preignition may be premature ignition timing or low octane number of gasoline, spark plug heat value is too high.(3) insulator top fragmentation. Knocking combustion is the main reason for the rupture of the insulator. Premature ignition timing low octane number of gasoline, the combustion chamber temperature is too high, may cause engine knocking combustion.(4) insulator top gray and black stripes. Leak, this striped flag spark plug should be replaced with new parts.(B), and spark plug deposits. Sometimes stuck between the top of the spark plug insulator and electrode sediments, can cause severe engine can not work, such as cleaning spark plugs can be remedied temporarily. In order to maintain good performance, we must identify the root cause of the failure.(1) oily sediment. On the spark plug the oily sediment, indicating that the lubricating oil into the combustion chamber. Just individual spark plug, valve stem seal damage. Each cylinder spark plug to stick with this sediment, indicating that the cylinder channeling oil, air filter and ventilation devices should be checked whether the blockage.(2) black sediment. The spark plug electrode and internal black sediment, indicating that the mixture is too thick, the engine running speed can be increased, and a few minutes, you can burn to stay in the electrode layer of black soot layer.