Types of spark plugs

Spark plugs are one of the key components that keep your engine running. Without it, there will be no spark thus no combustion leading to no power being made. Spark plugs also come in different types and sizes which are used in many different kinds of vehicles. Some of these spark plugs will be more efficient, while others will perform better.  With that said, here is everything you should know about the kind of spark plugs available on the market today.

Here is a quick list of common components you will find in a spark plug. 

  • Insulator

This insulates the terminal, center shaft, and center electrode from the housing. It also prevents high voltage from escaping from the housing. 

  • Terminal

This is the part of the spark plug that is connected to the high-tension cord which allows high-voltage current to pass through it.

  • Ring/ packing washer

This is the part of the spark plug that connects the insulator to the housing. It also makes sure that there is an airtight seal between the two parts

  • Center shaft

The center shaft connects the terminal to the center electrode. It is typically made of steel and allows the high-voltage current to flow from the terminal to the center electrode.

  • Housing

This is the protective outer shell of the sparkplug that surrounds and supports the insulator. This is also where the sparkplug attaches itself to the engine.

  • Glass seal

This is a component that is mounted between the center shaft and insulator that helps maintain airtightness in the sparkplug.

  • Gasket

Another part that helps make sure that the spark plug maintains a tight seal with the engine and its combustion chamber.

  • Electrode with copper

While this may vary from manufacturer to manufacturer, a standard spark plug will come with a special nickel alloy that is used for the center electrode. It is also used to help reduce the wear and tear on the part and to improve thermal conductivity.

  • Center electrode

This is the part of a spark plug that lowers the voltage to ensure that a reliable spark is made. It also makes sure that the quenching effect is reduced and that ignition performance is improved.

  • U-groove ground electrode

This part ensures that the surface contacted by the fuel to air mixture is large and that proper conduction can be achieved.

  • The tapered cut ground electrode

This is another part that reduces the quenching effect and also helps in improving ignition performance. 

The purpose of a spark plug is to use the high voltage current from the ignition coil to spark or ignite the compressed mixture of air and fuel in each cylinder in a gasoline-powered motor. Normally the number of spark plugs in a vehicle will be equal to the number of cylinders found in an engine. However, there are exceptions to this in the form of performance vehicles. That being said these performance-oriented vehicles may often have double the amount of spark plugs to ensure a cleaner burn. 

types of spark plugs


As its name suggests, a copper spark plug has a copper core located within it that is coated with a nickel alloy. These kinds of spark plugs are one of the best performing options available on the market that also comes at an affordable price. This is due to copper being a great conductor of electricity thus allowing the spark plug to generate a spark more consistently.

However, this does come at a price as copper spark plugs wear out faster than the rest of the other types of spark plugs available on the market. Thus copper spark plugs need to be changed out more often.


Compared to its copper counterpart, an Iridium spark plug will last significantly longer. This is due to Iridium being a much durable material but less conductive one. This means that while its spark is weaker than that of a copper spark plug, it will last much longer. This durable comes at a price, however, as Iridium spark plugs will tend to cost more but will need to be changed out less often. Overall it’s a balanced option if you want a spark plug that will perform decently but at the same time will not be required to be changed out often. 


This kind of spark plug is similar in design to a copper one except that it comes with a platinum tip at the end instead of a nickel alloy one. These will come in two forms either a single tip or a double tip. The single tip will only have the platinum coating on the center electrode, while a double tip will have it on the center and ground electrodes.

With the platinum coating, these spark plugs will last longer than their copper and iridium-based counterparts but will significantly lower in terms of spark generating performance. This is due to platinum not being a great conductor of electricity compared to copper or iridium. These kinds of plugs also have the disadvantage of being expensive. That said, these are ideal for those who want a long-lasting spark plug and don’t mind a lower performance output. 


These are the more uncommon kind of spark plugs available on the market that come with silver-coated electrode tips. These do not last as long as their platinum or iridium counterparts as the metal is less durable, but they do come with the advantage of handling thermal conductivity better. As these types of spark plugs are uncommon you will rarely see them being used on more modern vehicles. In terms of performance and pricing, these are in between copper and iridium. 

If you want the best-performing spark plug, then go for a copper-based one. While these will require changing often, they will offer you the best performance in terms of generating a spark. If you want a more balanced option then Iridium is your next best choice as it does a little bit of everything. If, however, you don’t mind a loss in spark performance and just want a spark plug that lasts long the go with the platinum-based options.

Short of pulling your spark plugs out of your vehicle yourself to see what type they are you can consult with your owner’s manual. There you will see which specific brand you should use on your vehicle as well as what type of spark plug is recommended. It will also show you when you should replace your spark plugs based on either time or on milage. 

It is highly recommended that you replace your vehicle’s spark plugs according to your owner’s manual. Having the correct spark plugs will ensure that you will be able to maximize the life of these parts and that your engine runs efficiently as possible. Another general rule of thumb to follow is to have your spark plugs replaced every time your car goes in for its preventive maintenance. 

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