Premature Electrode Wear - Preignition Damage

Preignition Damage:

Symptoms: Center electrode dissolves first and the ground electrode dissolves somewhat later. Insulators appear relatively deposit free.

Possible Causes:
- Excessive combustion chamber temperature.
- Incorrect spark plug heat range [1].
- Ignition timing is over advanced
- Other operating conditions are causing engine overheating.


[1] Spark plugs are designed to operate within a specific temperature range, called spark plug heat range. Variations in thickness and length of the center electrode and porcelain insulator change how fast the plug can dissipate heat and determine the plugs heat range.