What is a spark plug? A spark plug is an electrical device that fits into the cylinder head of some internal combustion engines and ignites compressed aerosol gasoline by means of an electric spark. No spark plug = no combustion = no road trip.
Why is it important and how does it work?
A spark plug has two important functions:
1. To ignite the air/fuel mixture. Electrical energy is transmitted through the spark plug, jumping the gap in the plugs firing end if the voltage supplied to the plug is high enough. This electrical spark ignites the gasoline/air mixture in the combustion chamber. The voltage at the spark plug can be anywhere from 20,000 to more than 100,000 volts.
2. To remove heat from the combustion chamber. The temperature of the end of the plug\’s firing end must be kept low enough to prevent pre-ignition, but high enough to prevent fouling. The spark plug works as a heat exchanger by pulling unwanted thermal energy from the combustion chamber and transferring heat to the engine’s cooling system. The heat range of a spark plug is defined as its ability to dissipate heat from the tip.
Let’s talk about replacements!
Spark plugs don’t require replacement very often and can go years and many miles before replacement is a must. However, most manufacturers would suggest having a replacement installed every 30, 000 miles. Type and condition of the spark plug is also considered. Example of this are copper plugs which have the shortest life span compared with plugs made from more durable materials.
So how do you know it’s time to get new spark plugs? Take note of the following signs:
- Difficult vehicle start – If your spark plugs aren’t working right, this can lead to misfires and erratic performance.
- “Knock”-like or rattling noises – which are the byproduct when the spark plugs fire at the wrong time causing the pistons and combustion to not work properly.
- Poor fuel economy – There are many factors that affect a car’s fuel economy, including busted spark plugs. Fuel is wasted whenever your vehicle fails to receive the proper, heat-generating spark at the right time.
- Inferior car performance – Spark plugs also work when you’re accelerating or changing gears. For this reason, you can expect a sluggish drive when your spark plugs are shot.
Thinking of replacing them yourself? Here’s a video tutorial:
Comment below if we miss anything or if there’s any topic you’d like us to discuss.