How to Crimp Spark Plug Wires (6-Easy Steps)

In general, to crimp spark plug wires, follow these steps.

  • First, strip the outer layer of the wire.
  • Then, determine the terminal type; single crimp or double crimp.
  • If it is a single crimp, fold back the conductor wire onto the silicone jacket and use the crimping tool to squeeze the wire and the terminal.
  • When using a double crimp, don’t fold the conductor wire. Instead, crimp the conductor and silicone jacket separately.
  • Finally, connect the wire terminal to the plug boot.

Now your custom-made sparkplug wires are ready for use.

Crimp-On Spark Plug Ends

Even though pre-terminated spark plug wire kit manufacturers claim these wires are universal, they are not. In truth, they are semi-universal. Sometimes, these wires might not have the necessary length and can be expensive.

Considering all of this, creating your own spark plug wires seems like an excellent idea. 

How to Crimp Spark Plug Wires?

Creating your own spark plug for the engine might seem a difficult task. But it isn’t. If you follow this guide, you’ll realize that it is all about execution. Here are the steps for crimping spark plug wires.

Things You Need

First and foremost, gather the necessary tools. For this process, we are going to use several tools. So, here is a short explanation of the tools that will be needed.

Pro Crimp Tool: Highly useful for crimping wires and terminals

Wire Stripper: Excellent tool for stripping wires

Plug Boot: Connects the spark plug and the ignition coil.

Terminal: Electrical connector for conductor wire’s end.

Step 1 – Strip the Wire

First, strip the outer layer of the wire using the wire stripper. Keep the strip length at 0.75 – 1 inches. For a double crimp terminal, you’ll need a smaller length. However, the above-mentioned stripping range is more than enough for both types of terminals.

Step 2 – Determine the Terminal Type

Depending on the type of the terminal, you’ll have to do some modifications to the crimping method. Because of that, this step is vital.

Double Crimp Wire Terminal

Most traditional spark plug terminals come with only one crimp. A double crimp terminal has two different spots to tighten the connection of the wire. For instance, you can find two spots for a conductor wire and a silicone jacket. On the other hand, a single crimp has only one spot. So, inspect the wire terminal closely and decide the terminal type.

Keep in mind: If you have a double crimp terminal, skip steps 3 and 4. After completing step 2, jump to step 5.

Step 3 – Fold the Conductor Wire

man holding a conductor wire
Video | rob miller

If you have a single crimp terminal, fold back the conductor wire onto the silicone jacket.

Now, slip the wire into the terminal. Push the wire until it gets inside the terminal saddle. It will prevent the wire from slipping out.

Step 4 – Crimp the Wire (Single Crimp Terminal)

Get the pro crimp tool and squeeze the spark plug wire and the terminal. Next, check the connection one more time.

Step 5 – Connect the Plug Boot

plug boot
Video | rob miller

Now, slide the spark plug terminal into the plug boot.

man sliding the spark plug terminal into the plug boot
Video | rob miller

If needed, use some grease to make the sliding easier.

Tip: After connecting the wire to the terminal, check the wire for continuity. Use a multimeter for this. This is an excellent method to check the resistance level and do it before sliding the spark plug terminal into the plug boot. (1)

Step 6 – Crimp the Wire (Double Crimp Terminal)

You’ll have to crimp the conductor wire and terminal separately if you have a double crimp. So, follow these steps.

man crimping the silicon jacket
Video | BSK Garage

  1. First, slide the wire into the terminal.
  2. Then, use the crimping tool to tighten the silicone jacket and the terminal.
  3. Next, tighten the conductor wire and the terminal.
  4. Finally, follow the instructions given in step 5.

Keep in mind: Always crimp the silicone jacket first. The silicone jacket covers more area than the conductor wire. So, the connection on the silicone jacket is much stronger. (2)

How to Put Ends on Spark Plug Wires

It is crucial to complete the above task successfully. With that in mind, here are valuable tips on crimping spark plug wires.

  • Before starting, read the labels and manufacturer warnings.
  • There are three configurations to crimp spark plug wires; removable terminal nut, solid terminal, and threaded terminals stud. Choose a configuration depending on your need.

Wrapping Up

After following the above 6-step guide on how to crimp a spark plug wires properly, you can understand crimping a wire is easy as striping a wire. So, now you don’t need to spend money on pre-terminated plug wire kits. Whether you use a single crimp or double crimp, you’ll get the job done quite easily.

Take a look at some of our related articles below.

(1) resistance level –
(2) silicone –

Video References

Talking Hands Tools

MSD Performance Ignition

rob miller

BSK Garage

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About Sam Orlovsky

b1d87d2ee85af3e51479df87928bdc88?s=90&d=mm&r=gCertifications: B.E.E.
Education: University Of Denver - Electric Engineering
Lives In: Denver Colorado

Electrical engineering is my passion, and I’ve been in the industry for over 20 years. This gives me a unique ability to give you expert home improvement and DIY recommendations. I’m not only an electrician, but I also like machinery and anything to do with carpentry. One of my career paths started as a general handyman, so I also have a lot of experience with home improvement I love to share.

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