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How do you gap spark plugs with a feeler gauge?

How to gap spark plugs with a feeler gauge

Shop for Feeler Gauges

Gapping Spark Plugs with a Feeler Gauge

Step 1 – Check gap meets spec

Use your feeler gauge to check the spark plug gap meets the specification for your vehicle.

You may need to adjust the spark plug gap from its out-of-the-box state.

Use feeler gauge to check gap between spark plug centre electrode and ground electrode

Step 2 – Bend ground electrode

To alter the gap, bend the ground electrode slightly away from or toward the centre electrode.

Using pliers to adjust spark plug gap after checking with feeler gauges

Step 3 – Use other tools if necessary

Spark plug gapping tools are available, however, sometimes a small mallet, wrench, or pliers can be used to adjust the gap slightly.

After adjustment. recheck spark plug gap with feeler gauge

Step 4 – Place gauge between electrodes

Re-check the gap by placing the feeler gauge between the two electrodes.

The gap must meet the vehicles specification so the spark plug can fire efficiently.

Gapping spark plugs with a feeler gauges Spark plugs in automobiles generally have a gap between  0.9-1.8 mm (0.035″–0.070″).

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