Spark Plug Gap
The spark plug gap is the distance between the centre and ground electrodes.
What is Spark Plug Gap?
It affects spark strength and ignition reliability. Manufacturers specify the gap. Many modern plugs are pre-gapped. Checking the gap with a wire gauge is more accurate than a flat feeler gauge on worn electrodes. Engines with high boost pressure often need smaller gaps. Plugs that have been dropped can have a changed gap or cracked insulator.
How it works
The spark jumps across the gap to ignite the mixture.
Why it matters for your car
A wrong gap can cause misfires. Iridium and platinum tips can be damaged when adjusting.
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