What is the difference between a 'cold' and a 'hot' spark plug?

A 'cold' spark plug is designed to dissipate heat readily, which means it can absorb and transfer heat away from the combustion chamber more effectively. This is important because engines that generate higher amounts of heat, such as those in high-performance or racing applications, require spark plugs that can handle that thermal load without overheating.

The ability of a cold spark plug to manage heat helps prevent issues such as pre-ignition or fouling that can occur if the spark plug gets too hot. On the other hand, a hot spark plug retains more heat, allowing it to reach a higher operating temperature, which suits engines that operate at lower combustion temperatures.

Therefore, recognizing that a cold spark plug is engineered specifically to dissipate heat is crucial to understanding its function and application in various engine types.