DIY

How to Gap a Spark Plug?

Reading Time: 3 minutes

Gapping your spark plugs is crucial as it affects the performance of your ignition system. An incorrect gap will cause poor mileage, misfires, and a lousy engine performance. Truly—and we can’t stress this enough—proper gapping is key. So, how do you do it? Here are three easy steps:

Things You Need

Start by finding your ride’s gap specification. Keep in mind that spark plug gap dimension depends on the engine type of your car. Take note, too, that every car’s engine is different and unique from each other so be cautious in choosing the right gap dimension to use. Now, if you are anxious when it comes to reading spark plugs, it’s best to check your car’s manual. Or, you can ask assistance at your local auto parts shop for a more precise dimension. To ensure that you have the accurate measurements, you can also check the spark plug cross reference chart. This reference chart is available online so accessibility is not a problem. After checking the required dimension, the next thing to determine is the spark plug gap gauge to use. There are three kinds: the coin-style gauge, the wire coin gauge, and the blade-style feeler gauge. Use the gauge you are most comfortable with.

The three kinds of spark plug gap gauges. | Source: Dsmtuners.com

Examine Your Spark Plugs

The condition of your spark plug is of utmost importance so be sure to examine and remeasure each of your newly-bought spark plug replacement before using them. If you are remeasuring your old spark plugs, make it a point to clean them first and check them for are any cracks or bubble formation. You can refer to your spark plug chart so you can be aware of the exact condition of your old spark plugs. It ranges from normal to normal with red coating, fuel fouled to ash fouled, and overheated to worn out. After that, measure each spark plug by passing the gauge between the electrodes. See if adjusting is needed. If the gauge passes through the electrodes quite smoothly, the gap is too wide. On the other hand, if the gauge can’t fit between the electrodes, the gap is too narrow.

Reading spark plugs using a coin style gauge.. | Source: My.prostreetonline.com

Adjust Accordingly

After knowing the current gap measurement of your spark plugs, you need to adjust the distance between the electrodes according to your engine’s requirement. Gauges nowadays feature a specific edge for bending your ground electrode. Use it to adjust the gap by gently bending the ground electrode down to narrow the gap and by tugging it up to widen. Repeat the process until you reach the required gap for your spark plugs.

If you are in need of new spark plugs, you can check our selection here: https://bit.ly/36ilQFf.

Now that you know how to properly gap your spark plugs, watch this video for easy-to-follow steps on how to replace them:

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