There are seven factors affecting the cylinder sealing performance, mainly including cylinder wear, piston ring damage, piston wear, valve seat damage, valve guide wear, cylinder head gasket damage, valve clearance and other aspects.
What are the commonly used diagnostic methods? The main ones are measuring the cylinder pressure, the crankcase bleed air volume, the cylinder air leakage and the air leakage rate, the vacuum of the intake pipe, the vibration measurement of the abnormal noise caused by the excessive wear of the cylinder piston group, and the crankshaft. The wear metal in the tank is a measure of the particle content.
For the measurement of the cylinder compression pressure, it is mainly the pressure at the end of the four-stroke engine compression. Due to the pressure of the cylinder, the viscosity of the oil and the cylinder piston set, the adjustment of the valve train is correct, the sealing of the cylinder head and other factors, so when measuring the pressure of the engine cylinder, the cylinder piston can be diagnosed. In the case of sealing, if the piston ring, valve, and cylinder head gasket are well sealed, the clearance of the valve must be appropriate.
We are mainly testing the engine sealability by first blowing the dirty air around the spark plug with compressed air, and then removing the spark plug. For gasoline, the ignition high-voltage line should be pulled out to reliably carry the ground. In order to prevent electric shock and fire, the tapered rubber plug of the special cylinder pressure gauge is inserted into the spark plug hole measured by the cylinder. It must be pressed and fixed. For the special throttle, it must be placed in the whole. In the open position, the starter should drive the corresponding crankshaft to rotate. If the gauge indication of the pressure gauge has a certain hold, the final pressure reading should have a certain stop rotation. Finally, remove the pressure gauge and record the reading.
