Spark Plugs

Nothing will happen in your petrol engine without a spark. The spark comes from the spark plug in your engine. Therefore, it is vital that you check your spark plugs regularly to ensure that they are working correctly.

How Do Spark Plugs Work?

The spark plug forces electricity across a gap in your engine. It requires a high voltage so the electricity can jump the gap and cause a good spark. The voltage of a spark plug can be anything from 40,000 volts to 100,000 volts! To ensure the car is safe at this point, the spark plug must have a ceramic insert which insulates the voltage. The ceramic insert ensures that the spark occurs at the end of the spark plug, and not anywhere else within the plug. The voltage will have to travel down the insulated spark plug, from the spark plug the voltage jumps the gap, where it travels to your engine block and then grounded.

Different Types Of Spark Plugs

There are several different grades of spark plugs. The higher the grade, the cooler the spark plug. Some cars require a hot plug and some require a cold plug. Cold plugs have a ceramic insert which has a larger contact area with the metal part of the spark plug. This means the plugs run at a cooler temperature. The ceramic insert in a hot plug is smaller and so has a smaller contact area with the metal part of the spark plug. Your car manufacturer selects the correct spark plug for each type of car. It is extremely important to use the correct spark plug for your car. For example, if you use a spark plug which is of a lower grade spark plug than what your car requires, the fuel might ignite before the spark actually ignites.

How To Diagnose Problems With Your Spark Plug

Normal
A normal spark plug should be a light brown or tan colour. Your spark plug is running correctly if it looks like this.It also shows that the general condition of your engine is good.

Normal Life
It is essential that you change your spark plugs at regular intervals. As a spark plug gets older, the width of the gap in the spark plug increases. This means the spark plug becomes less efficient and puts strain on your engine. It can also result in fuel wastage.

Overheating
Overheating in your engine can cause damage to your spark plug. If this occurs the tip of your spark plug will look like it has a glazed appearance. There are certain reasons that overheating occurs. It could be due to using the incorrect grade of spark plug, the spark plug not being fitted into your car correctly, or the water/oil level being too low.

Dry and wet fouling
Dry fouling looks like the top of your spark plug is covered in black soot, and will be a matt black colour. Wet fouling looks like the bottom of your spark plug is covered in black gloss and will be sticky to the touch. Dry and wet fouling can occur due to a number of reasons. If you use the incorrect grade of spark plug for your car. Your engine could have an electrical problem, your choke could still be on or you could have had extended periods of slow driving. If you do see some of the symptoms described above, you should check your car for all of the problems which could lead to dry or wet fouling.

Lead fouling
Your spark plug will be a yellowish brown colour if lead deposits build up on its insulator tip. If this does occur in your car, try to use a petrol which has less lead content.

Deposits
If you use oil which has the wrong viscosity for you engine the oil could leak through the piston rings or valve seals. The symptoms of this problem will show as the insulator nose being covered in a white crust.

Erosion, Corrosion, Oxidisation
If the surface of the electrode of your spark plug appears rough, or a green colour, erosion, corrosion or oxidisation may have occured. This may have been caused due to age or because you have not used your for an extended period.

Lead erosion
There are several symptoms of lead erosion that you should look out for. The ground electrode of your spark plug will appear worn, the central electrode will be chipped and the insulator nose will be a yellowish brown colour. Lead erosion is due to a chemical reaction between the lead compounds in your petrol and the nickel alloy electrodes in your spark plug.

Abnormal erosion
Oxidation and erosion of the lead in the petrol accelerates the growth of the gap in the spark plug. If this occurs, the spark plug will need to be changed.

Breakage
Using a spark plug which isn't the correct grade for your car, your water or oil level being too low or the air/oil mixture being too lean could lead to damage of the insulator nose. This is due to abnormal expansion within the combustion chamber within your spark plug.

Melting
Melting of the spark plug may sometimes occur. This problem will be diagnosed by the surface of the electrode appearing uneven. Melting is caused by the high temperatures within the combustion chamber within the spark plug.

Benefits Of An Aftermarket Spark Plug

Aftermarket spark plugs wont always give you a better spark. This normally comes with good maintenance but they will perform much better than standard plugs due to their superior quality materials. This is helpful because spark plugs get hot, which causes the insulator tip to start knocking and affects performance. If you replace your plugs and leads at the same time you should end up with a smoother running engine.

It Is Essential That You Look After Your Spark Plug

You should ensure that your spark plugs are in good condition. After time, the terminals on your spark plug may become glazed and will lose their conductivity over time. So you should check your spark plugs regularly. If you have normal spark plugs, (not performance or long life spark plugs), and they do appear to be glazing, you should clean them with a wire brush or fine sand paper.

Bookmark: delicious digg reddit furl yahoo google faves stumbleupon Facebook

There are no comments for this guide yet.