If the spark plug is improperly installed, it will lead to the arc deformation of the spark plug gasket, which will lead to air leakage and power reduction when the engine is working, and block the heat dissipation channel, so that the heat absorbed by the spark plug from the combustion chamber cannot be transferred out. The accumulation of heat makes the internal temperature of spark plug rise sharply, thus burning the ignition end including insulator skirt, center electrode and side electrode.
Lighter will lead to overheating of the main electrode of the spark plug and shorten the service life. In severe cases, it will lead to premature ignition and detonation, and even the spark plug electrode will fall off and pull the cylinder.
Air leakage, high temperature mixed oil and gas leaking from around the spark plug. Fuel consumption increases and power decreases. After a long time, acid glue will form between spark plug and cylinder head, which will bring trouble to later maintenance and replacement.
Install the spark plug with a torque wrench. The factory process requires the tightening torque, which is generally 15-30 Nm. For machines with aluminum cylinder heads, the tightening torque is 25 ~ 30 Nm. For cast iron cylinder heads, the tightening torque is 30 ~ 35 Nm. Without a torque wrench, the new spark plug feels difficult to tighten, and then turn 1 to 2 revolutions. I felt very tired when tightening the old spark plug. Two or four more turns.
Extended data:
Working principle of spark plug:
1. The electric plate of the spark plug ignites the air-fuel mixture in the cylinder through repeated power generation. At this time, other parts of the ignition system generate timed high-voltage electric pulses, which form sparks and explode to provide the energy needed for engine power output.
2. The structure of the spark plug is made of a slender metal plate passing through a ceramic material with insulating function. A metal shell is arranged around the lower part of the insulator, which is screwed on the cylinder head through threads, and electrodes are welded at the bottom of the metal shell to form a grounding effect with the vehicle body. In addition, the central end of the electrode must be separated by a tiny discharge gap.
3. Then, the high voltage current from the distributor will conduct electricity through this central electrode, and then discharge in the discharge gap at the bottom. At this time, the spark plug will work, producing sparks to burn the mixture, and the engine will gain energy and output power.
It can be seen that the spark plug is a device to ignite the mixture of gasoline and air that enters the engine for combustion. Working under the harsh conditions of high temperature and high pressure, it is one of the vulnerable parts of gasoline engine, which plays a very important role in the operation of the engine and has a great relationship with whether the car saves fuel and runs smoothly.
References:
Baidu encyclopedia spark plug