What Happens If Spark Plug Gap Is Too Small?

what happens if spark plug gap is too small

You may face some issues with starting your car engine anytime, anywhere. But, having no clue about the spark plug gap may make the situation more troublesome.

Even though this little spark plug is installed inside every single car engine, people don’t seem to be aware of its activities that much.

Well, don’t worry. In this article, we’ll guide you through what happens if the spark plug gap is too small or even bigger.

Additionally, we’ll provide some suggestions regarding the topic. So without further delay, let’s jump in.

The Objective of Spark Plug

Basically, a spark plug is a small tool through which energy is transmitted. It’s the prime source of supplying the spark, which makes the energy jump between the gap with high voltage.

Then that spark ignites the fuel gasoline or air mixture. Finally, it creates the explosion that ultimately makes the engine respond to power.

The built-in material of spark plugs is very durable. As a result, it’s capable of withholding tons of explosions. But sometimes, the corrosion and explosions lead to infirm and smaller sparks.

It might ultimately hamper the efficiency of the engine. Additionally, it may create issues like failure of firing, misfiring, etc. Nevertheless, the spark plug is the reason why engines respond to energy sources.

What is Spark Plug Gap?

Image source: help.summitracing.com

Basically, there need to be some gaps between electrodes in order to make the spark plug work. However, based on the gap, the performance of the spark plug depends.

If the gap between them is too small, then there might be weak sparks that lead to poor efficiency of the engine. On the other hand, the engine might face performance issues if the gap between electrodes is too long.

However, the spark plug distance can be adjusted properly. It can be done by mechanics or even all by yourself. You’ll just need gap gauges to do that. These tools are inexpensive, and you can easily adjust the gaps according to measurements.

What Happens if the Spark Plug Gap is Too Small?

There will occur several issues if the spark plug is too small. Because a small distance between them will lead to an infirm spark.

This will ultimately impact the durability of the engine. Because the spark is created in the combustion chamber with the act of ionization.

So if the gap is too small, then there will be partial ionization. Sometimes, spark plug gap too small to misfire or holds too little power to start the engine.

So, these are some issues you may face for too small spark plug gaps. Nevertheless, you can resolve this issue in simple steps as well. 

What Should Be the Ideal Spark Plug Gap?

Basically, the spark plug gap depends on the engine and the manufacturer’s measurement. However, it’s suggested to keep the plug gap between 0.020 and 0.040 inches.

Mostly, engine makers install it around 0.035 of an inch. On the other hand, it must not cross 0.055” if it’s not pre-installed by the engine maker. You can find the spark plug gap chart according to the engine you are using.

What is a Spark Plug Gap Tool?

Spark Plug Gap Tool

Every engine has its own spark plug gap measurement recommended by the factory. So, you can simply adjust the gap using a gapping tool according to that measurement. No matter whether the spark plug gap is bigger or smaller, you can always resolve the issue.

In that case, a spark plug feeler gauge is an appropriate tool for it. It’s basically a set of discs with declining edges. Or else, it consists of some round wires with accurate diameter.

With the help of this tool, you can easily measure the distance between the central electrodes and the ground properly.

How To Adjust Spark Plug Gap?

Before adjusting the spark plug gaps, make sure they are clean. Sometimes, debris or dirt may weaken the potential sparks. We suggest you use a wire brush for that. After cleaning the spark plug, get yourself a feeler gauge first.

Now calculate the measurement based on the handbook of the manufacturer. Next, select the measurement on the feeler gauge. After that, move the feeler gauge between the central electrodes and the ground.

If you find it passing through the distance without touching the electrodes, then you should adjust that gap. And to do so, get the ground electrode and bend it further away or towards the main electrode.

This might take a few attempts to set the gap accurately finally. This is how you can resolve spark plug gap too small symptoms and issues.


Will the spark plug gap impact the performance?

Yes, it’ll because the spark plug is the main factor behind engine performance based on the structure of the engine. However, gap adjustment is crucial for operating the engine. A small gap may cause a flimsy spark that will affect the performance.

Is it better to have a smaller spark plug gap?

Yes, it’s definitely better to have a smaller spark plug gap because it’ll lead to an intense and short spark for the engine to respond.

What happens if the spark plugs aren’t torqued?

It’s necessary to torque the spark plug based on recommended pressure. Otherwise, it may leak the compressed air.

Is it better to have a larger spark plug gap?

When the spark plug gap is larger, it requires more voltage to cover the gap. So, it leads to an increase in the size of the spark and ultimately causes maximum burn efficiency.


Well, we’re certain that now you’re well aware of the situation of what happens if the spark plug is too small.

Plus, now you have received the instructions on how to fix the situation on your own. If you find it struggling to resolve the spark plug issue, we recommend you go for a mechanic.

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