Do You Need a Torque Wrench for Spark Plugs? [with Chart]

A torque wrench is a tool used for tightening bolts and nuts to the desired torque value. The tool allows bolts and screws to be tightened to the correct tension to prevent damages from overtightened bolts or joints from falling due to under-tightening.

This feature makes it essential for tightening spark plugs. So, you might start thinking if you need a torque wrench for spark plugs.

Although torque wrenches are a quick solution to tighten your spark plugs properly, you can still do the task without them. You can just tighten it according to the instructions provided by the manufacturer without the need for special tools.

Continue reading because we will discuss torque wrenches and how to use them.

Is a Torque Wrench Needed for Spark Plugs?

A torque wrench for spark plugs is needed if you want to do substantial repairs on your key powertrain and engine components. Overtightening cylinder-head bolts can cause expensive damage and catastrophic loss.

You can prevent this by using a torque wrench. Some people recommend spark plug torques as low as 7-foot lbs.

However, finding a ⅜ in. drive torque with 7-foot lbs in the middle range might be difficult. So, this leaves you to resort to inch-pound torque wrenches.

What Is Torque?

In mechanics and physics, torque is the linear force’s rotational equivalent. It can also be called rotational force, a moment of force, moment, or turning effect.

In addition, it represents the force’s capability to produce a change in the body’s rotational motion.

YouTube video

The video starts with the definition of torque as a measuring force that causes something to rotate around a point. You can compute this by using the formula of force x length.

He says that more force acts on the nut when using a longer wrench from the formula. You can also use a larger circle to turn a smaller circle.

By changing the size, the speed and torque can be changed. He then explains the difference between low and high gears and their importance in bikes and cars.

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What Is a Torque Wrench?

A torque wrench applies specific torque to fasteners like a lag screw, bolt, or nut. It can be in a socket wrench form with unique internal mechanisms.

In addition, torque wrenches are used in crucial situations of the tightness of bolts and screws. It lets the user set the torque applied to the fastener to match the specifications for the application, permitting proper loading and tension of the parts.

How to Use a Torque Wrench on Spark Plugs

Spark plugs must be torqued according to the manufacturer’s specifications. Here are the steps to use a torque wrench for spark plugs.

1. Gather the needed materials

The initial step is to have all the necessary materials before working. These are spark plugs, torque wrench, ratchet, and gauge gap.

2. Open the ignition coil

The second step is to tidy the ignition coil area using a cleaning brush or air duster to ensure no dust particles are left in the ignition component.

Remove the ignition through the locking tab and connector from the ignition. Next is to unplug the screws and remove the existing spark plugs.

You can use an air compressor to clean the ignition pipe inside.

3. Gap adjustment

Using a gauge gap and hammering the plugs slightly can help adjust the spark plug gap. However, it’s best to rely on the manufacturing guide before installing the new plugs to know the required interval.

4. Install the spark plug

Finally, use the torque wrench for tightening the installed plugs after correcting the gaps. Try fastening it slowly as the fragile components can easily break when excessive force is applied.

After getting the right torque level, connect the wires, screw back the components, and check the ignition.

What Makes a Good Spark Plug Torque Wrench?

Spark plugs are one of an engine’s most sensitive parts. You need to ensure that they are properly tightened, and it can be done using torque wrenches.

Consider the factors below when buying a torque wrench for spark plugs.


Spark plug torque wrenches can deliver a precise torque amount as long as you follow the manufacturer’s instructions.

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Wrenches with +/–3% precision are the most accurate. Meanwhile, +/–4% can be useful for standard ones.


If you are looking for an affordable option, mechanical torque wrenches can bring great value. They have click feedback to help prevent spark plug’s over-tightening.

On the other hand, electric torque wrenches are more accurate and have several useful features. However, they are more expensive.


Choose a wrench made of all-steel alloy material to assure you of its durability. It should also have chrome plating to prevent the build-up of rust and corrosion.

Measurement Unit

Almost every torque wrench comes with in-lb or ft-lb and Nm units. You can choose according to your preferences.

3 Best Torque Wrench for Spark Plugs

Not every torque wrench is suitable for use with spark plugs. As this work requires accuracy, you can choose from the recommended products listed here.

1. TEKTON 1/2 Inch Drive Click Torque Wrench

The Tekton torque wrench has a wide dual scale range in ft-lb and Nm to tighten spark plugs easily.

It is pre-calibrated with an accuracy of +/–4% to allow driving of the fasteners in counterclockwise and clockwise directions.

Lastly,  there will be no struggles reading its dual-range scale values no matter what your lighting condition is. This wrench has a hard plastic case, so you can conveniently bring it around.


  • It can be reversed in both directions
  • With a dual-range scale
  • Has good accuracy
  • Constructed with durable all-steel


  • Creates a mild clicking sound

2. eTORK 1/2-Inch Drive “Click Style” Electronic Torque Wrench

The digital eTORK torque wrench lets the user set the torque value in four different units, making it convenient for versatile fasteners.

Aside from its convenience, it only requires mild torque settings.


  • Operates and measures in both directions
  • Constructed with hardened steel alloy and lightweight
  • Has four units of measurement


  • The value often changes after locking the knob

3. DEWALT Torque Wrench

The DEWALT torque wrench comes with a durable case for portability and protection during storage.

It also works as a handle to easily get under low-level items like freezers to avoid damaging or shaking them.

Some of the highlights of this wrench are its capability of forward and reverse torque for easier adjustment and a quick-release trigger to let you know where the socket is.

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  • Comes with a heavy-duty protective case
  • Has a bi-material grip for a secured grip and a locking trigger


  • Difficult to read numbers


4. GEARWRENCH Micrometer Torque Wrench

The GEARWRENCH’s sealed, thin profile, and teardrop head design improves durability and enhanced performance for effective usage.

It has a torque accuracy of +/- 3% clockwise between 20 and 100% capability. Also, the pull adjustment collar allows the user to make easy and quick changes to the torque.


  • Has visible markings for easy reading
  • Featured with a pull adjustment collar for easy torque adjustments
  • Comes with a midpoint on the handle for accuracy


  • The flexible head easily becomes loose when too much torque is applied

5. PREC2FR100F Wrench

The PREC2FR100F wrench offers a highly accurate torque setting as its adjustment knob doesn’t have spring tension.

Its length is designed to provide enough leverage to maximize torque applications and is also a great tool to access hard-to-reach nuts and bolts.


  • Great for indoor and outdoor use as it’s designed to be rust-resistant
  • Has a flexible head and lightweight construction for convenience


  • It doesn’t come with a protective covering on the handle to reduce wear and tear

Frequently Asked Questions (FAQs):

Is it necessary to calibrate my torque wrench?

Torque wrenches are delicate tools prone to breakage, losing their calibration over time. They can lose calibration even when used with utmost care.

The internal mechanism and spring can loosen and wear over time from normally using it. This is why it’s necessary to check your torque’s calibration often and as needed.

You can check it at least once a year, after 5000 cycles, or after an impact or fall. Also, you can take it to a calibration technician.

Are there different kinds of torque wrenches?

There are four different kinds of torque wrenches: deflecting beam, beam, slipper, and click, and we’ll discuss each of them in this section.

1. Beam

The most basic torque form comprises two beams.

A lever is the first, and it is used to apply the torque to fasteners being tightened while also serving as the tool’s handle. It will deflect proportionally when force is applied to the handle.

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The second beam is only attached on a single end to the wrench head and is free on the other end, serving as the indicator beam.

A more sophisticated beam-type variation consists of a dial gauge indicator on the body that can be configured, giving electrical or visual indications or both after reaching the desired torque.

2. Click

Click torque wrenches are the most affordable and common among all types. They are easy to use by turning the handle until reaching the desired torque setting.

They are great tools for various settings. However, caution is not to overtighten bolts and nuts when working with it because you can continue tightening even after the clicking sound.

3. Dial

Dial torque wrenches are great tools for torque measurement because they offer quality control in determining and monitoring torque. These tools are usually used for auditing, verifying, and testing torque to applied joints.

In addition, when using the memory pointer, these wrenches can capture the final torque applied to fasteners.

4. Electronics or Digital

Electronic or digital torque wrenches offer a precise torque reading on digital displays to prevent under-tightening and over-tightening fasteners. They can electronically measure the turning force for better accuracy than analog ones.

In addition, they are ideal for applying consistent torque and verifying the torque on assembled objects for quality control and safety.

What happens if your spark plugs aren’t torqued?

Plugs must be tightened because they work to seal off the combustion chamber. When plugs become loose, the cylinder compression will be lost, and oxygen contained in the cylinder and lack of compression can cause misfiring of the engine and loss of its power.

Also, a lean cylinder and loose plug will be hotter and cause other problems like piston and cylinder damage, pre-ignition, head gasket damage, lean codes, and more.

On the other hand, overtightening the plugs can cause cylinder head damage that is also difficult to fix. Too much torque causes damage to the plug as well.

Furthermore, overtightening can easily create stretching that can split the threads and worsen the extraction.

Should you oil the spark plug threads?

It is not recommended to oil the spark plug heads because it can cause over-tightening of the spark plug.

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Having an overtightened spark plug can cause it to break off and stretch. It can also remain partially stuck or broken inside the cylinder head.

Can you tighten spark plugs by hand?

Although you can use your bare hands for tightening the spark plug, it may not be enough to create the force to do the work correctly.

It can end up under-tightened, and having a loosened spark plug can cause issues and damage.

So, it’s best to use torque wrenches after inserting and crewing the initial rotations with your bare hands.

This can help you get the required tightness of the spark plug. The torque needed for tightening spark plugs differs depending on the diameter.

It’s recommended to start by screwing spark plugs by hand when installing them. And then, get your torque wrench to seal to the specified fastening torque after colliding with the cylinder head.

The Takeaway

To conclude, a torque wrench for spark plugs is helpful but not necessary when fixing or changing spark plugs. However, the tool’s precision makes it popular for most people.

Also, torque wrenches help prevent loose and overtightened plugs. However, if you don’t have a torque wrench, you can tighten it following the manufacturer’s instructions.

No matter what, changing spark plugs and using the correct torque wrench size is important. Hopefully, you have learned how torque wrenches work if your spark plugs need changing and the importance of getting them changed.

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