Introduction: How to Gap a Spark Plug

Picture of How to Gap a Spark Plug

In this instructable you will learn how to properly set the gap on a Spark Plug for your vehicles Ignition System. 

You will need:

1) Spark Plugs
2) Spark Plug Gap Measuring tool
3) Spark Plug Adjustment tool

Step 1: Measure the Gap

Picture of Measure the Gap

The first step is to figure out the size of the gap that your vehicle requires.  My vehicle requires a 0.054" spark gap.  We will now measure the gap on one of the new spark plugs using our spark plug gap measuring tool.  As you can see this gap is about .002" larger than what we need.

Step 2: Adjust the Gap

Picture of Adjust the Gap

In order to adjust the gap we will use our spark plug gap adjustment tool.  The tool uses leverage in order to increase or decrease the size of the gap.  Slightly adjusting the gap takes very little force.  In this case we will gently pull the lever toward the opposite side of the spark plugs electrode.  Be careful not to contact the ceramic or metal core in the center of the plug as this might damage the ceramic.  If the ceramic breaks you will need to throw the plug away and purchase a new one.

Step 3: Re-measure the Gap

Picture of Re-measure the Gap

Once you've completed the adjustment it's time to re-measure the gap.  This gap adjustment was successful.  We now have a gap of .054"  If you don't get the proper gap on the first adjustment, simply repeat the process until the desired result is achieved. This instructable was made using tools from the Auto-Bay at TECHSHOP.


alterator (author)2012-07-16

looks more like 0.056 to me.
regarding, that the thickest part edges against the gap, on the right.



They were all double checked with a feeler guage. They are precise.

ede566 (author)alterator2012-07-24

é que a foto esta de lado ,se girar vai dar certinho a medida com o centro do pino ,dificil e achar essa moeda medidora ,eu nunca vi uma pra vender ,mas a ideia é boa e esse sujeito deve ser revendedor gringo deste produto.

samalert (author)2012-07-10

how to measure how much gap is needed for my spark plug is there a means to find or just trial and error

if its trial and error then how can i get the exact gap needed for my car
Car owned - Maruti SX4 (India)

jgregory83 (author)2012-06-29

FYI: You can not gap most iridium plugs this way. In fact most iridium plugs come pregapped for your vehicle.

For sure, these aren't irridium plugs.

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