Automotive engine cylinder seals include valves, piston rings and cylinder head seals between the cylinder block and so on. There are many ways to check the diagnosis. (1) When diagnosing the barometer test, the engine that can start running should be brought to the normal temperature of 80-90 ℃. The parts of the parts should reach the normal working state with the clearance, and then stop to remove the spark plug of each cylinder to reduce the crankshaft rotation When the resistance and carburetor choke and throttle transferred to fully open, each cylinder followed by the pressure gauge pressed into the spark plug hole and then start the barometer reading indicates the test result. (2) compressed air inspection method will check the cylinder piston to the compression top dead center, then into the exhaust valve closed, with 490 ~ 780KPa compressed air through the spark hole into the cylinder, and then rely on the hearing to determine whether the leak Sound, you can identify the site. For example, there is a leak at the filling port, which is the gap between piston and cylinder wall is too large or the piston ring is badly sealed. In addition, you can also use a plastic pipe into the spark plug hole, take a deep suction, through the plastic pipe into the cylinder, if the flue gas from the adjacent cylinder spark plug holes, that is, cylinder pad nose wear. (3) Throttle comparison method When the engine is running, the throttle is increased and the crankcase is heard to emit a continuous "嘣, 嘣" sound at the port where the engine is pressurized. The sound is compressed when the cylinder wall is compressed and exploded Fled into the crankcase and generated; the same time, from the plus port pulsating fumes (ie channeling gas), serious knocking cylinder sound similar to the Canadian oil port there will be a large number of gas emerge, the exhaust pipe will There is a lot of blue, black smoke. Loosen the throttle, the sound leakage weakened or disappeared, to take repeated comparison, and then use single-cylinder off-fire method to determine the leakage of the cylinder. (4) heuristics test suspicious cylinder to the top of the piston by adding 20 ~ 30g of new oil, and then check the pressure gauge, if the pressure rose significantly, that is, the piston ring wear; if the pressure is unchanged, the valve or Cylinder liner leakage. (5) The feeling judgment method will not work cylinder spark plug removed, plug with the thumb plug hole, crankshaft crankshaft, with the feeling of judgment cylinder pressure. If cranking crankshaft is labor-saving, and feel the reaction pressure of compressed gas is not, then the lack of pressure on the cylinder. When the engine is running, high-pressure gas rushes out of the rim of the cylinder pad, giving a "shhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhh The cylinder spark plug after the sound disappeared; turn off the measured cylinder pressure can not be measured, the cylinder gasket wear burn through. (6) cotton bolus clogging method Single-cylinder off-fire method to determine the adjacent two cylinders do not work, the two-cylinder spark plug can be removed, with cotton bolting plug hole. Shake the crankshaft very slowly, if the two groups of spark plugs hole at the cotton bolting was not washed out, that is, the cylinder pad nasal beam ablation and collusion. (7) observation method In the engine running, if found in the radiator water outlet bubbles, serious water into the cylinder, the exhaust nozzle (water droplets), that is, between the cylinder and the hole between the water jacket Cylinder pad burn through. Remove the spark plug inspection, the electrodes have drops of water; Use the motor so crankshaft rotation, the water or water vapor from the spark plug screw hole can be judged as the cylinder water jacket burn through. If the spark plug electrode surface carbon deposition too much, and there is moist oil, piston ring seal is bad and channeling oil. (8) Acoustic examination method Suddenly felt engine power shortage, the sound is not normal, and there is an obvious valve channeling sound, mostly (overhead) into the cylinder valve. If the intake valve into the cylinder, in the cab will be able to hear a larger return air (carburetor tempering); If the exhaust valve into the cylinder, you will hear abnormal exhaust sound. If a cylinder is not working properly and the engine can hear a "hissing" sound, use hearing to identify or touch the edge of the cylinder head liner with compressed gas and this is usually where the cylinder head bolts are not screwed to the required Torque or cylinder head breakage. (9) Commissioning Engine idling instability, jitter, and even no idle; and empty car in a flat road to accelerate well, but no heavy load high-speed uphill, this phenomenon is generally wear cylinder liner or valve lax. Idle speed adjustment, the muffler can hear "Chi Chi" sound (such as when the air pump inflated cheer sound), that is, due to the exhaust valve closed lance caused by running gas phenomenon, with a single cylinder off the fire law can be found out Cylinder exhaust valve is faulty. (10) off the fire test method When the car engine is running, there is a flushed out thicker flue gas pipe, and can hear the sound of channeling sound. Followed by the off fire method followed by the cylinder off the fire observation plus oil nozzle smoke and channeling gas phenomenon. After a fire off a cylinder to reduce the smoke, channeling sound weakened, you can determine the site of the fault, the fault is mostly piston ring counterparts or stuck stagnation.
