2. In most cases, to replace spark plugs you will need the following tools: a spark plug wrench (it is a tall socket wrench with an insert inside to protect the spark plug insulator), as well as a special tool for checking and adjusting the gap between the electrodes (Fig. 19.2). There's also a special tool for disconnecting the spark plug's high-voltage wire, which is recommended. because the wire tips are connected to the spark plugs very tightly. A torque wrench should be used to tighten new spark plugs. Allow the engine to cool before replacing the spark plugs.
Figure 19.2. Tools required to replace spark plugs: 1. Spark plug wrench - has a special insert inside to protect the ceramic insulator of the spark plug; 2. A torque wrench - although not absolutely necessary, it is the only way to tighten the spark plug correctly; 3 Ratchet - a common tool for working with socket heads; 4 Extension - depending on the model, access to the spark plugs may not be entirely convenient and you may need a simple or cardanic extension wrench; 5 The tool for checking and adjusting the spark plug gap is available in various modifications. When purchasing this tool, make sure it comes with a dipstick for your engine
3. When replacing spark plugs, it is better to purchase a new set in advance, adjust the gaps of the new spark plugs, and replace the spark plugs one at a time. When purchasing spark plugs, make sure the new spark plugs are suitable for your engine. The recommended spark plug type is listed in the Technical Data at the beginning of this chapter and on the label under the hood. If these two sources conflict, follow the manufacturer's label recommendations.
4. Allow the engine to cool before removing the spark plugs. While the engine is cooling, inspect the new spark plugs for defects, check and adjust the gaps between the electrodes.
5. To check the gap, insert a feeler gauge of the required thickness into the gap between the electrodes (figure 19 5,a). The required clearance value is indicated in Technical data i am at the beginning of this chapter. The feeler gauge should pass between the electrodes with some friction. If the gap does not correspond to the technical data, bend the side electrode of the spark plug in the required direction (figure 19 5.6). If the side electrode is not positioned directly over the center electrode, bend the SIDE electrode. Check for cracks in the spark plug's porcelain insulator. This candle cannot be used.
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6. Remove the high-voltage probe tip from the spark plug as described in the next paragraph. Pull only on the tip insulator, not on the wire. If you have a special tool for disconnecting high-voltage wires, use it.
7. If you have compressed air, use it to blow out all the dirt from the spark plug socket. If you don't have compressed air, you can use a regular bicycle pump. The purpose of this action is to, if possible, protect the engine cylinder from foreign objects getting into it when the spark plug is removed.
8. On the models described, the spark plugs are deeply recessed, so to unscrew them you will need an extension to the spark plug wrench (figure 19.8). On V-engines, the rear spark plugs are particularly deep and will require a very long (approximately 250 mm) extension, maybe even with a cardan joint.
9. You return the candle. Inspect the condition of its insulator and electrodes and compare them with the illustrations on the inside back cover. This comparison will allow you to judge the general condition of the engine. Before installing a new spark plug, apply anti-seize compound to its threaded part (figure 19.9).
10. Screw the spark plug into its threaded hole first by hand, as far as possible. To avoid damaging the spark plug hole thread. you can put a piece of hose of a suitable diameter on the spark plug insulator and screw in the spark plug by rotating the hose (figure 19.10). If the spark plug is not threaded properly, the hose will simply slip through and prevent the threads from being stripped. Then tighten the spark plug with a torque wrench.
11. Before placing the high-tension wire on the spark plug, inspect the wire as described in the next paragraph.
12. Place the high-voltage wire tip onto the spark plug.
13. Repeat the described procedure for the remaining candles. Replace the spark plugs one at a time. so as not to confuse their high-voltage wires.