For the engine to run properly, the spark plug electrodes need to be properly adjusted. The adjustment of the electrode gap affects the ignition temperature which has a direct relationship with the combustion of fuel and air in the engine. Opening the distance produces a greater spark, useful with modified engines to maximize efficiency. You can learn how to adjust the electrode gap to your liking. Read the first step for more information.
Steps
Part 1 of 2: Measure the Distance
Step 1. Find out the distance specifications of your vehicle
Whether you are buying, have just bought the spark plugs to install or want to check the operation of the ones you already have, you will need to know the correct distance that must be between the electrodes of each spark plug.
- Depending on the vehicle, the measurement is different, although most are between.028-.060 inches. You can look in your car manual or go to an auto parts store and let them search for you.
- Modified engines require a shorter distance to account for the power being fed into the engine. The general rule says: more power, less distance.
Step 2. Choose the right tool to measure distance
There are several tools used to measure the gap between the spark plug electrodes, some are more suitable for modern spark plugs which sometimes have precious metals. Many of these tools have a flat end used to bend the lower electrode and adjust the distance.
- A roller thickness gauge is the cheapest choice and works by passing one end of the roller through the slot until it stops. The border is marked with a line that marks the thickness at that particular point. It is a valid tool for testing the effectiveness of old candles but can inadvertently increase the distance while using it.
- A comb thickness gauge works the same way but has different sized teeth on the edge around the wheel.
- A blade thickness gauge is an effective and versatile tool. Built as a utility knife, it has a series of blades of different thicknesses some with teeth at the end and others without, to be placed in the slot to measure the distance between the electrodes. You can use different slats to measure greater distances, which is useful when you need to make adjustments.
Step 3. Clean the Candles
If you just took them out of the box then they will be fine, but if you are checking a spark plug that you used in your car then a good idea is to wipe it with a clean cloth. A whitish soot may form on the contact points, so it is best to clean well to make accurate measurements.
You can use quick-drying alcohol (90%) on the contact points, especially if they are particularly dirty. Piling up or any blackening of the contact points can be a sign that the candle is exhausted. If they are particularly dirty, consider changing them
Step 4. Measure the distance by passing the measuring tool between the electrodes
Place the feeler gauge blade between the electrode tips or pass the thumbwheel through the electrodes to determine the measurement.
Part 2 of 2: Adjusting the Distance
Step 1. Determine if the distance needs to be adjusted
If the thickness gauge of the appropriate size passes between the electrodes without touching them then the distance is too great. If you can't get it through then there is too little space and it will have to be enlarged. If, on the other hand, it is around the specified measurement then you can safely install the spark plug.
Most spark plugs and iridium candles manufactured today do not need to be spaced before they are fitted. But if you have a custom engine you may be interested in mounting the spark plugs at a different distance. Adjust accordingly
Step 2. Use the feeler gauge to adjust the lower spark plug
When you hold the spark plug with the electrode facing the floor you will have to bend the lower spark plug towards the other electrode, inwards, to decrease the distance, or outwards if you want to increase it.
- Do not bend too much, just a few millimeters are enough. No need to press hard, be careful. It's tough, but not that tough.
- If you have problems using a tool to adjust the distance, consider using a flat surface such as a table to exert a slight pressure on the electrode and adjust the distance.
Step 3. Measure the distance again and adjust accordingly
Be very careful not to touch the electrode in the center of the spark plug and damage the core. If it breaks you will have to throw it away and buy a new one.
Step 4. Be very gentle
Breaking the electrode will make you waste the effort, and it doesn't take long for it to happen. Always exert slight pressure to bend the electrode and bend it a little.
Advice
- If the tip colors are different you may have engine problems.
- Try to keep the distance between the candles as even as possible.
- Don't squeeze the candles too tight. most of the heads are made of aluminum and the threads can be easily damaged.
- Candles are relatively inexpensive, so change them whenever possible.
