Parts of Spark Plug

NGK-BlogThe spark plug is a device responsible for starting the combustion process in an engine. The two primary functions of spark plug include igniting the air-fuel mixture within the combustion chamber and to remove the heat from the combustion chamber. It is screwed in the top of the cylinder head.
1. Ribs
Ribs act as an insulator and provides additional protection against secondary voltage. The ribs of the spark plug are molded from aluminum oxide. They improve the electrical insulation and prevent the leakage of electrical energy.
2. Insulator
An insulator is made up of porcelain material and provides mechanical support to the central electrode along with insulating the high voltage grounding anywhere else. It also transfers the heat from combustion chamber to the cooling system.
3. Shell
The steel shell is a threaded metal hex. It enhances the durability of the spark plug and is always plated to protect it from corrosion.
4. Seals/sealing gasket
For the effective combustion process to take place, proper sealing of the combustion chamber is vital. Here, the seals ensure that there is no leakage in the combustion chamber. Usually, the sealing gasket is made up of a multi-layer braze.

5. Terminal
The top of the spark plug contains a terminal to connect to the ignition system and it’s construction varies depending on the use of the spark plug.

6. Central electrode
Central electrodes are made from a special alloy which should be immune to the spark and chemical corrosion. The temperature in the combustion chamber varies radically thus, the central electrodes must withstand these.
7. Side/ Ground electrode
The side/ Ground electrode is made up of high nickel steel and is generally welded to the metal case.

Do spark plugs age?

NGK-BlogEven the sharpest of all tools wears out eventually. Same is applicable to our beloved spark plugs. Getting premium spark plugs to have a wide array of benefits such as better fuel efficiency, reduced emissions and improved overall longevity of the engine. But all things age with time, and so do the spark plugs. But unlike some of our devices, ageing spark plugs might not be very evident for a layman. As spark plugs go through thousands and thousands of miles along with your vehicle, their internal components tend to wear out and even though they can withstand extreme temperatures, their durability goes down with time. A spark plug can not and will not last forever, because of a few reasons which we are about to discuss. As the spark plugs and its components interact with a variety of substances such as air, fuel, a mixture of fluids etc. a build-up starts to develop on them. This build can lead to a number of various scenarios where the spark plugs might get delayed in its working, cause erratic behaviour and jerky performance while operating the vehicle. In addition to this, the jump gap can also expand making it more difficult for the spark plug to function as expected. Another thing to keep in mind regarding this build-up is that it tells you a great deal about the problem or the underlying cause of it. Various kinds of build-ups, the texture of the build-up and the colour of the build-up are distinct for each root cause. For instance, the colouring of the build-up on the spark plug is different when there is an oil leak and different when there is a gap or the spark plug is not a proper fit and so on. Furthermore, every spark plug is rated for a certain number of kilometres that it can work through and might fail beyond that. As these spark plugs age, they start to fail in performing their intended function and might even prevent the engine from starting altogether. So the best way to overcome this problem is to replace your ageing spark plug before it damages the rest of the machinery in any way.

Common myths about spark plugs – II

NGK-BlogThere are so many misconceptions and myths about the spark plugs, that they cannot be crammed into one. So let us continue debunking a few more myths about the heart of the engine of our vehicles.

Copper spark plugs are better than Iridium and Platinum spark plugs
This myth is based around the fact that Copper is a better conductor of electricity, hence it can provide the electrical spark in a better way. However, this is not particularly useful when it comes to spark plugs. Iridium and Platinum are preferred because of two main reasons. They are good conductors of electricity as well. And the second one being, they have a higher melting point which makes them efficient even while operating at a higher temperature that a spark plug experiences.


Fit it and forget it
The implication of this myth is based around premium spark plugs. According to the myth, all the benefits of a good spark plug like lower emissions, better performance of the vehicle, decreased fuel consumption are permanent. While these are the advantages of a premium spark plugs, but they do not last forever. To get the best of these benefits, you need to replace your premium spark plugs regularly. Even the best of the spark plugs need a change on a regular basis, and not waiting for your current one to fail is a good practice.

Glow plugs are the same as spark plugs and can be interchanged
One of the most baseless myths happens to be quite dangerous a well. Regardless of the similarity in their name, spark plugs and glow plugs are built for a different purpose and have varying functionality. Glow plugs are exclusively made for diesel engines and cannot be used in Spark Ignition engines. Similarly, spark plugs are purpose-built for petrol engines and can not be used in Compression Ignition engines. Interchanging them, will not only prevent the engine from starting but can also damage the plugs and the engine itself. However both can’t be replaced because of their dimensions.

What is the heat range of a spark plug?

NGK-BlogThe spark plug of a vehicle is one of the hottest parts of the vehicle and this is because of its very own functionality. The way a spark plug works is that it uses the electrodes present in it (namely the central electrode and the ground electrode) to deliver an electric spark with the help of electrical current. As a result of this spark plugs, especially the electrodes inside them reach a very high temperature.
While talking about the working temperature of the spark plug, the temperature at the tip is what is referred to. Generally speaking, the range of the temperature is 500-800 ºC. This temperature is important since this is the temperature at which the spark plug is expected to work as intended for its use. For this reason, often spark plugs have an inbuilt heat insulator (copper core) in them to manage the amount of heat that gets generated around them. In case of wrong fitment/ recommendation, like too hot spark plug can cause pre-ignition and may cause damage to the engine. On the other hand, if it is too cold the plug would not be able to deliver the spark and may cause carbon fouling/ misfiring problems. The hot and cold temperature that a spark plug can withstand is called the heat range of the spark plug and is usually denoted by numbers. This heat range is dependent on various factor, most important being the material used in the making of the spark plug. Usually, metals that have a high melting point are used for this very reason such as Platinum or Iridium. Keeping this heat range in mind is very important to ensure the longevity of the spark plug and making sure to get the most out of your spark plug.

Why are they called “Glow” plugs?

NGK-BlogAs you all might be aware, unlike petrol engines, diesel engines do not use spark plugs. Instead, diesel engines use another device called glow plugs. The regular spark plugs deliver an electrical spark that starts the petrol engine while glow plugs and diesel engines work on an entirely different principle. Glow plugs act as a heating device that aids the starting of diesel engines. In cold weather, diesel engines can become a hassle to start and need a little bit of assistance as the cylinder head and cylinder block absorbs the heat that is generated in compression and thus creating an obstacle to start working. Glow plugs have a heating element at the tip which reaches a high temperature and uses electrification and this heat is then used to start the diesel engine.

Now the question arises, why are they called glow plugs?! The heating element at the glow plug makes the use of electrical resistance. The more the resistance of an element, the more amount of heat it will start to gather. And this is the very functionality of a glow plug and more specifically the heating element. As the electricity starts to flow through this heating element of high electrical resistance, it starts to heat up and thus the temperature of the glow plug and its surroundings starts to rise. As the temperature of this element keeps rising, it begins to accumulate energy and start to release it. This energy is emitted in the form of light that lies in the visible spectrum and appears to glow, giving it the characteristic name, glow plug. This visual effect is similar to the glow of an electric bulb that works on a similar principle and thus glows as well. This glowing property is not necessarily the intended function but is merely a side effect of proper working.

Spark Plugs And Their Electrodes


As we all know, spark plugs are the key component that delivers electric current to ignite the fuel by an electric spark inside a combustion engine. Now this key component has two key components inside it, which makes this functionality of delivering an electric spark possible in the first place. And these are called electrodes.
Generally, a spark plug has two electrodes, namely, the central electrode and the side electrode (also known as the ground electrode). In older times, the electrodes of the spark plugs were not temperature resistant to any extent because of the way they used to be designed. This created unforeseen issues like the cold spark plugs would stop working outside their advised temperature range and similar for the hot spark plugs. This is what forced the manufacturers to come up with a complete redesign of the spark plug to make them more temperature resistant, which meant, a new way to integrate the electrodes present in the spark plugs.
Hence it became important to use the most efficient metals for making these electrodes. For instance, iridium and platinum spark plugs last much longer than the traditional copper ones. The usage of such noble metals like platinum, tungsten etc. also had another benefits. These metals allow for a much small central wire, while still maintaining the efficiency. This is the reason why new and modern spark plugs have been able to do the same task in a much smaller size and the property that makes these metals more efficient if their relatively higher melting points.

NGK Iridium Spark Plug makes ignition perfect


Iridium spark plugs are globally the best performance category of spark plugs having superior technology. These spark plugs use very precious Iridium metal at the tip of centre electrode of diameter 0.6mm. and has a thermo-edge design for central electrode. These features give anti carbon fouling performance, smoothest running, and excellent acceleration with increased mileage and are used and appreciated by most racing bikes and cars all over the world.
Raghav, who is an online media reporter, rides his bike to work every day. The traffic jam in his city has become a daily nuisance. Not to mention, the severity of warm and rainy weather makes it all the more difficult. Let’s take you through his story to illustrate how NGK Iridium Plugs have made his life comfortable.
Natural overheating of vehicle
Often his bike gets overheated due to weather and erratic traffic. If it’s like this, it certainly interferes with his work. “When it was new, it worked smoothly. I rode everywhere and it worked alright, now the overheat is really fast, then the fuel feels wasted” he complained when he went to a local motorcycle repair workshop in his city.
According to Rahman, who is the head of the motorcycle repair shop, this is because the engine needs stable ignition to maintain engine performance. “To maintain engine performance, choose your spark plugs carefully. Don’t look at the price, because even though the shape of the spark plug is small, its function and utility are very crucial for the smooth running of the engine ” he explained.
Spark Plug Functioning
Spark plugs are installed to burn fuel that has been compressed by the piston. The temperature around the spark plug in the combustion chamber goes higher even more than 2500 0C . After experiencing high temperatures, then the temperature will drop dramatically when fuel and air enter the cylinder. Changes in temperature over and over again require that spark plugs contain materials that are strong, heat resistant and of superior quality.
On that occasion, Rahman suggested Raghav to use NGK iridium spark plugs. They have a hard metal element and are anti-corrosion and heat resistance. In addition to these advantages, besides having a high-quality material, NGK Iridium spark plugs also have a strong electrode which improves its durability.
NGK Iridium Spark Plug has a more focused combustion at one point, so it can service hot engines that require a capable spark.
Due to having more focused combustion, combustion becomes more perfect. This triggers the gas response and acceleration becomes more enhanced, the motor also becomes more economical and of course also increases the exhaust gas to be more friendly.

“My motorbike has used NGK Iridium Spark Plug from last year, the result is that I feel the engine is more powerful, more efficient, acceleration is more stable, and durable. I also often recommend other drivers to use the NGK Iridium Spark Plugs, because it has proven to stand the test of time ” concluded Rahman.

A guide to choosing right: Platinum and Iridium Spark Plugs


The varied categories and types of spark plugs available in the market may confuse the layman vehicle owner, especially when it comes to changing the spark plug. Although copper spark plugs are the most commonly used spark plug these days, one major disadvantage is that they have a shorter life span and need to be replaced more frequently as compared to the other spark plugs
In this blog, we will explain the two premium types: Platinum and Iridium spark plugs.
Platinum: At a comparatively lower price, platinum has twice the longevity when compared to copper spark plugs. This is so because of its fine tip central electrode which is made up of platinum, that provides slower wear and tear and higher efficiency.
Iridium: These spark plugs have significant advantages over the ones made from other materials. They provide higher performance, majorly because they ensure complete combustion.
Since Iridium has an outstanding longevity, once installed, you won’t have to change the spark plug very frequently. These spark plugs are quite consistent and wear-resistant. So, in general, iridium spark plugs allow you to have a lifespan and performance compared to copper and platinum plugs.
As a practice, it’s not recommended to adjust the gap of iridium spark plugs, as this metal can be damaged during the process.
We hope you would have gotten a better idea on spark plugs after reading this blog and it will enable you to make the right choice.

Common Myths About Spark Plugs


There since not everyone is well versed in the domain of spark plugs, there are quite a few myths about them floating around and this blog is aimed to bust a few of them.

If it fits, it will work
This is one of the most common myths about spark plugs. Just because the dimensions of the spark plug happen to be a right fit, it simply does not imply that the spark plug will work as intended. There are numerous factors that come into play about the functionality of the spark plug such as electrodes, temperature range and the materials used to name a few.

More expensive means better
This myth exists for all consumer products, especially when it comes to spark plugs. While it might be true that good quality spark plugs do have premium price tags, but the cost of the spark plugs solely is not a determining factor in its reliability.

The color decides
The myth about the color of the spark plugs is partly true. While it is a norm in the industry to color code the spark plugs in the industry as per their usage and electrodes, this may not always be the case. And unless you are a certified professional, do not stick to the color grading to change or fix your spark plugs.

All spark plugs are the same
It is often the case where we tend to take proper care for our vehicles from a macro perspective but fail to do so on a micro-level. This can lead to lots of problems down the road while ignoring the small but crucial things and spark plugs are one of them. Spark plugs, not only do the job of starting the engine of the vehicle, but they also can affect lots of other factors such as emissions, engine longevity, fuel efficiency etc.

These tiny devices can have a huge impact to start busting the myths and do it by the book.

What should diesel drivers know about plugs?


Spark plugs are not the first thing that comes into mind and that is for a specific reason. The spark plugs are not used in diesel vehicles, at least not under the same name. Diesel engines, unlike gasoline engines, do not use spark plugs to induce combustion. Rather, when operating in adverse conditions, they use a different type of plug similar to spark plugs, called glow plugs. Diesel engines make the use of default air temperature to combust the fuel spontaneously and start a burn. This becomes somewhat harder to achieve in colder temperatures since the air temperature is substantially lower than the ignition temperature of the diesel and because of this reason, it becomes more cumbersome to start diesel vehicles. And this is where glow plugs come into play. Pre-chambered engines have these inside the pre-chamber and direct-injected engines, have these glow plugs in the combustion chambers. As the name suggests, glow plug is a metal-based plug with a heating element. This heating element can achieve high temperatures with the help of electric current and use its electrical resistance to heat up the air surrounding it. This heating element can get so hot that it can essentially turn red hot and start radiating light, thus giving it the name “glow plug”. As the temperature of the air inside these chamber start to rise up along with the glow plug, it naturally starts getting close to the ignition or combustion temperature of the fuel, which is diesel in this case. In most of the vehicles, a glow plug indicator shows when to start you vehicle.