Spark plugs

The spark plug is comprised of a metal core which is housed in a ceramic insulator. This, in turn, is surrounded by a metal casing which has a thread that is screwed into the cylinder head.

When considering the basic construction of the spark plug, there have been no profound changes over the past 50 years. Like before, the spark plug is comprised of a metal core which is housed in a ceramic insulator. This, in turn, is surrounded by a metal casing which has a thread that is screwed into the cylinder head and normally has a hexagonal section on the top which fits the spark plug socket and enables the installation and removal of spark plugs with a spark plug spanner.

The main purpose of the construction lies in ensuring that the electrical circuit at high voltage on the spark plug is closed with a spark, which jumps from the middle electrode to the earth electrode.