Removing
Disconnect the tips from the spark plugs. In this case, pull not on the wire, but on the tip.
Unscrew the spark plugs with a wrench of the appropriate size.
Examination
Check the working part of the candles. If you have some experience as a result of this check, you can draw a conclusion about the condition of the engine.
Electrodes and insulation:
- gray - the correct operation of the candles;
- black - too rich combustible mixture;
- light gray - too lean combustible mixture;
- oiled - interruptions in the operation of the candle or worn piston rings
Clean the spark plugs with a brass brush or sandblaster.
Check the insulation of the spark plugs for breakdown. The presence of leakage currents can be recognized by thin uneven traces on the surface of the housing. If these traces cannot be completely removed, the spark plug must be replaced.
Check the distance between the electrodes with a feeler gauge. It should be 0.7-0.8 mm.
To adjust the distance between the electrodes, bend the side electrode by tapping it from the side with a suitable steel object. You can also use a small screwdriver, resting it on the edge of the threaded surface.
Attention! Do not bend or lean on the center electrode as this will break the spark plug!
Installation
Clean the threads on the spark plugs and on the threaded holes in the cylinder head.
Screw the spark plugs into the cylinder head by hand until it stops.
Attention! Do not twist candles!
Tighten spark plugs to 25 Nm. Attention! If you do not have a torque wrench handy, tighten new spark plugs with a flat sealing surface to an angle of approximately 90°, and spark plugs with a conical sealing surface to approximately 15°. At the same angle, tighten the plugs with a flat sealing surface that were in operation. If the spark plugs are too tight, loosening them can strip the threads on them or in the cylinder head. In this case, it is necessary to restore the thread using special inserts (UTC or Heli-Coil).
Put tips on candles in accordance with the order of operation of the cylinders. The first cylinder is on the right side of the engine, looking in the direction of travel.
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