The glow number recommended by the plant should be abandoned only if the operating conditions differ significantly from normal conditions and engine malfunctions occur. If the spark plugs are constantly covered with soot, this means that the self-cleaning temperature of the spark plugs has not been reached (short distance trips) and it is necessary to install candles with the nearest increased glow number. If the engine is operated exclusively at full load, then spark plugs with the next reduced glow number are required.
Removing
Remove all spark plug tips, pulling only on the tip, not on the wire. To facilitate the removal of the tips of the candles, a special clamp can be used, for example, HAZET 1849.
Note: The 6-cylinder engine has a commercially available tool located at the hood support for removing and installing spark plug tips. You must use this tool.
If possible, blow out the niches of the spark plugs with compressed air.
Unscrew the spark plugs with a suitable wrench.
Examination
Check electrodes and insulators. Based on the condition of the working surfaces of the candles, with some experience, we can draw conclusions about the condition of the engine. The following rules apply:
- medium gray - correct carburetor adjustment and correct spark plug operation;
- black color - the fuel-air mixture is very rich;
- light gray color - the fuel-air mixture is very poor;
- the presence of oil - the failure of the corresponding candle or the wear of the piston rings.
Clean spark plugs with a copper brush or sandblaster.
Examine the spark plug insulators for traces of leakage current. The presence of a leakage current is evidenced by thin uneven traces on the surface. If traces of the leakage current cannot be completely removed, replace the corresponding spark plug.
Use a feeler gauge to check the distance between the spark plug electrodes. Prescribed gap value see spark plug table. Replace spark plug if necessary.
Installation
Clean the threads on the spark plugs.
Screw the spark plugs into the cylinder head by hand as far as they will go.
Attention: Do not distort the candles.
Tighten the spark plugs to the correct torque, see spark plug table.
Caution: Too tight spark plugs can strip or damage the threads in the cylinder head. In this case, repair the spark plug thread with UTC or Heli-Coil inserts.
Install the spark plug tips according to the firing order of the cylinders. By swinging in different directions, check the reliability of fastening of the tips and high voltage wires. Flash sequence in 4-cylinder engine: 1-3-4-2; in a 6-cylinder engine: 1-5-3-6-2-4.
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