Spark plugs are manufactured in various heat ranges from?

Spark plugs are designed with a specific heat range that plays a crucial role in engine performance and efficiency. The heat range refers to how effectively the spark plug can transfer heat from the combustion chamber to the engine. A spark plug that operates within an optimal temperature range is essential for preventing issues such as pre-ignition or fouling.

The correct option describes the heat range as proceeding from hot to cold. A hotter spark plug will retain more heat, which can be beneficial for high-performance engines operating at higher temperatures, while a colder spark plug dissipates heat more efficiently, making it suitable for engines that operate at lower temperatures or under conditions where there is less heat generation.

Understanding this concept helps in choosing the right spark plug for specific engine requirements, ensuring that the engine runs smoothly and effectively under varying operating conditions.