How to Set Gaps in Spark Plugs

Most basic and integral tasks of vehicle maintenance is changing or replacing a set of spark plugs. However removing the old plug for installing the new plug is just half of the work done. For ensuring a better vehicle performance, one should know how to set gaps in the spark plugs. Here is a simple guide to set gaps between spark plugs. Follow the directions.

Things Needed

  • Spark plug
  • Spark plug gap gauge or gapping tool

Gaps Spark Plugs


In the process of knowing to set gaps in the spark plugs, it must be remembered to always work on one spark plug at a time. It is almost impossible to work on more than one spark plug at a time. Working in this way will help to minimize confusion and having the spark plugs firing sequence being mistimed.

After the old spark plug has been removed, the gap on the new spark plug has to be checked. The repair manual or checking under the bonnet will help to determine the correct gap. The reason is that a number of manufacturers provide the details of this information on a sticker pasted on the inside of the bonnet. This task can also be performed by checking the gap on the old spark plug using a gapping tool. However it depends on the old spark plug that has a correct gap measurement.

When the proper gap measurement has been found out, the gaping tool has ot be inserted into the space next to the electrode or hook. This needs to be bent out for reaching the exact measurement that was obtained through one of the methods mentioned earlier. In case the produced gap is too much then the space has to be closed by pushing the hook against a solid surface.

The gap between the tip and the hook has to be checked by comparing it with the information available to you. After this, the new spark can be reinstalled in its proper place. This process has to be repeated with the remaining spark plugs and you will be able to gap all of them.

It is possible that you have never gapped the spark plugs with a better reason. This is not usually required unless the car does not contain a manufacturer specified engine or the engine was modified. The generic spark plugs are already gapped for ensuring the finest performance. If the engine does not start or experience regular cold starts, then this is the possible reason to gap the spark plugs in unmodified vehicles. In fact it is very easy to set the gap on the spark plug.

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