All About Spark Plugs

Posted on October 24, 2017

mechanic in NashuaYour car needs many things to make it work. From your engine to your exhaust the mechanics, all parts rely on each other to function properly. When your mechanic in Nashua opens the hood of your car, they look at a variety of things under the hood. For the engine to work, it will rely on the gas that is in the tank. There is a little combustion in the car that will start the engine and allow the car to run. One of these items that helps your vehicle run correctly is the spark plug.

Mobil Oil describes the spark plug’s primary job as creating “an artificial bolt of lightning within the combustion chamber of the engine.” This bolt will then provide energy so that the spark can light the fire of the combustion chamber. At this point, there could be over 100,000 volts that run through the spark plug. It is important to note, however, that there are multiple versions of spark plugs available. Each one of these spark plugs, while they do the same thing, have unique mechanics that change it slightly.




While the spark plug doesn’t hold onto heat, it only creates it. When it comes to the thermal plug, the temperature range is that ability to “dissipate heat from the combustion chamber.” This temperature must stay maintained so that nothing happens. Which means it needs to be “high enough to prevent fouling, but low enough to prevent pre-ignition.” The thermal of the spark plug will only relate to the heat range. Not the plug itself.


Cold Spark Plug

A cold spark plug with has a short path for heat flow. So, that means that the heat transfer between the spark plug will be relatively quick. The cold spark plug will even have a short insulator nose. This nose will not allow for a lot of heat absorption through the spark plug.


Hot Spark Plug

The hot spark plug, on the other hand, has a longer insulator nose. The heat transfer is more extended than a cold plug as well. Where the nose and transfer are longer than a cold plug’s, this cap will cause a slower heat transfer rate to the cylinder head.


Voltage Rise

The ignition coil typically generates the high voltage that comes through the spark plug. When the voltage develops a difference between the center electrode and the ground electrode, it will cause the ignition of your engine. However, there is an air gap. It will not fire immediately. It needs to get to at least 20,000 volts for the space to be breached and the spark plug to work.



The spark plug works strictly through electricity. This allows it to help turn the engine and get your car started. Without a properly working spark plug, you can be sure that your vehicle will not start properly. If you feel you are facing an issue while starting your engine, step into Gurney’s Auto today and talk to a mechanic in Nashua.

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