What brand are the original Cadillac spark plugs?

[MacCaleb]

Cadillac's original spark plugs are the NGK LZKAR6AP-11 platinum spark plugs from Japan. Main types of spark plugs include: standard spark plugs, extended insulator spark plugs, electrode spark plugs, seat-type spark plugs, pole-type spark plugs, and surface-gap spark plugs. Spark plugs are installed on the side or top of the engine. In early models, spark plugs were connected to the distributor via ignition cables. Over the past decade, most car engines have switched to having ignition coils directly connected to the spark plugs. Under high voltage, the air between the center electrode and side electrode of the spark plug rapidly ionizes, forming positively charged ions and negatively charged free electrons. When the voltage between electrodes reaches a certain level, the number of ions and electrons in the gas increases like an avalanche, causing the air to lose its insulating properties and forming a discharge channel, resulting in a "breakdown" phenomenon. At this point, the gas becomes a luminous body, known as a "spark." Along with thermal expansion, a "crackling" sound is also produced. The temperature of this electric spark can reach 2000-3000°C, which is sufficient to ignite the air-fuel mixture in the engine combustion chamber.