different types of spark plug comparison

If you own a car then you will be aware of the importance if spark plugs as they are directly linked to the performance of your car and anything wrong with the spark plug will not be good for your driving experience as well.

Although they are one of the smaller parts in a car and one of the inexpensive parts as well, the spark plugs need to be taken care of properly. If your car needs new spark plugs and needs replacement you should be able to do it fairly easily and quickly by yourself. Some cars do have complex engine design around spark plugs and they are required to be dealt with by a professional.

So which kind or spark plugs are there in the market? Which is better suited to your car? These are the question we are going to discuss in this publication and we hope this useful piece of information will help you to choose a better spark plug for your vehicle. So let’s get started with it.

How to Choose Spark Plugs?

This is one of the most asked question related to spark plugs and the answer to this question is fairly simple. You can refer to the owner’s manual or guide provided by the car manufacturer to know which spark plug they have suggested to use in that specific vehicle. Every engine type has it’s own timing in the combustion process. This whole process is done with the help of spark plug’s spark production and if the spark produced is not sufficient enough or is produced at the wrong time will disturb the performance of the engine. This is the main reason manufacturers suggest spark plugs for the engine to it’s users because they have tested that specific spark plug and found it to be the best in terms of performance.

There are spark plugs that are “hotter” or “cooler” these spark plugs are suggested by the drivers to their fellow drivers but in reality they are best suited for customized engines and the drivers have done a little experimenting of their own to find out which spark plug performs better with their customizations to the engine. So if you have a stock engine it’s better to just use the spark plug which has been recommended by the manufacturer.

To get further into detail about spark plugs and if you want to decide on your own which spark plug to install in your car, we will put forward the differences between different spark plugs so you can make a better decision. Let’s get into that.

Types of Spark Plug and Their Difference

Before getting into the differences between the types of spark plug you should keep in mind two critical points that define the functionality of spark plug.  Keeping in mind these two factors you will be able to get the most out of your spark plug selection.

  • The first factor you have to keep in mind that the spark produce by the spark plugs is between two points. These points are known as ‘center electrode’ and ‘side electrode’. The spark between these two electrodes is from the sharpest point of both electrodes. Now to maintain the strength of spark between these two electrodes and overall spark plug you should keep in mind that the sharp points must be strong enough to stay sharpened for a long time.
  • The second factor is the diameter of the center electrode. The center electrode’s diameter determines the current needed to generate the spark. If the diameter of the center electrode is larger it will require more current to generate a spark compared to the center electrode having smaller diameter.


Now you will see four different types of spark plugs in the market that are available for you to purchase. These spark plugs are classified into four types due to the material used in their manufacturing. Out of these four types, three are widely used, which are:

  • Copper Spark Plugs
  • Platinum Spark Plugs
  • Iridium Spark Plugs

Now which one should you choose between these spark plugs? This point we will discuss below. But a word of advice first. You should always consult the owner’s manual of your vehicle to know which spark plug is recommended by the manufacturer to use in the engine. Consider the recommended spark plug to use in the car as well.

Copper Spark Plugs

The first type of spark plug that you will find in the market and the most inexpensive of them all will be copper spark plug.copper spark plug Copper spark plug’s core is made up of full copper but the center electrode is made of nickel alloy. The center electrode on copper spark plugs also has the biggest diameter of all the spark plugs i.e. 2.5mm. Now a thing has to be noted here which is the diameter of the center electrode, as we have previously said that the larger the diameter of the center electrode the higher voltage it is required to produce a spark. So it’s not the best performing spark plug when it is compared with other spark plugs. The nickel alloy on the center electrode also presents the sharp end which handles the spark considering the nickel alloy, it is not the strongest material and will wear out fairly quickly leading to spark plug replacement quickly.

The copper spark plugs are widely used in old cars which have low voltage distributor based ignition systems and their use in latest cars equipped with high voltage distributor less ignition system (DIS) and coil on plug ignition systems (COP) is non existent.

The only use of copper spark plugs in modern cars is with the high performance engines which are designed and manufactured around copper spark plugs. These engines are the only exception and in this scenario copper spark plugs are known to be high performance spark plugs. We recommend that if you have stock engines you should consult owner’s manual for the recommendation of spark plugs given by the car manufacturer to choose the right type of spark plug for your car.

Single Platinum Spark Plugs

The single platinum spark plug is based on the copper spark plugs but the difference between the two is the platinum plate welded on top of the center electrode.single platinum spark plug The platinum plate carries the sharp end of the spark plug which handles the spark. Since the platinum plate is stronger than copper so it lasts longer for around 100,000 miles. Also the running temperature of the platinum plate is higher which is good in terms of preventing carbon buildups overtime.

Latest vehicles operating on electronic distributor based ignition systems are better suited to the platinum spark plugs. We recommend that you consult the owner’s manual and act according to manufacturer’s recommendation on which spark plug to use also don’t downgrade to copper spark plugs if manufacturer has recommended the platinum spark plugs but there is an option to upgrade to double platinum spark plugs.

Double Platinum Spark Plugs

Double Platinum Spark Plugs are specifically designed for a certain ‘waste spark’ distributor ignition system which requires the spark on the spark plug to jump from center electrode platinum plate to the side electrode’s platinum plate on the compression stroke.double platinum spark plug On the exhaust stroke the spark returns from side electrode’s platinum plate to center electrode’s platinum plate, since the combustion process is going through exhaust stroke, spark is wasted and ignites nothing. This is how the double platinum spark plugs perform in certain Waste Spark DIS.

You cannot use copper or single platinum spark plugs in these systems because they are not designed for this type of ignition system. The electrodes on the copper and single platinum spark plugs are not designed for reverse spark. Dual platinum spark plugs have two platinum plates one on center electrode and one on the side electrode, both hold their sharp ends very well due to strong platinum material being used and they don’t wear out quickly.

We again recommend you to consult the owner’s manual and if the manufacturer has recommended dual plated spark plugs you can use dual platinum spark plugs or upgrade to iridium/platinum hybrid spark plugs. Downgrading to single plate platinum or copper spark plugs is not a very good option.

Iridium Spark Plugs

Now the iridium spark plugs, iridium is a stronger material than platinum so naturally iridium spark plugs are stronger than platinum ones and they last up to 25 percent longer on average.iridium spark plug The diameter of the center electrode on the iridium spark plugs is smaller because of iridium being an expensive material and you will see up to .4mm diameter of the center electrode in iridium spark plugs. The smaller center electrode is not just there for manufacturer to save money but also it is the most efficient performer of all the spark plugs.

Car manufacturers which have installed coil up ignition system in their cars mostly recommend iridium or iridium/platinum spark plugs to be installed in their cars. If your car’s owner manual specifies that you should only use iridium spark plus when replacing the old ones then don’t downgrade your spark plugs to single platinum, dual platinum or copper spark plugs because they will not work well with your car’s engine and will reduce the overall performance of the engine.

The side electrode of the iridium spark plugs tend to “quench ” the flame due to being the colder side of the spark plug. To counter this quenching U or V shaped channeling is created on the receiving side of the spark so that the spark channeling through the side electrode will allow the flame to grow quickly as well as provide a larger channeling area.

We hope you find this publication useful.

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