Converse of object

• replace: When replacing spark plugs take great care not damage the threads in the cylinder head.

• foul: It was running too rich, fouling spark plugs and we were unable to determine the cause.

• employ: Twin Spark ignition, as its name suggests, employs two spark plugs, but they are of different sizes and perform different roles.

Adjective modifier

• twin: Twin spark plugs per cylinder also make for faster, more efficient combustion and cut polluting emissions.

• spare: All down to not fitting some spare spark plugs.

• longlife: Low maintenance requirements are met by the incorporation of hydraulic tappets, automatic timing belt tensioners and longlife spark plugs.

Modifies a noun

• tip: The additional electrodes disturb the flow of gases around the spark plug tip and performance may even be reduced.

• gap: What should my spark plug gap be set to?

• wire: Replaced all of the spark plug wires and the coil wire, and haven't had the problem since.

Preposition: per

• cylinder: Ignition - Digital electronic ignition, with one spark plug per cylinder, integrated with fuel injection system.