The phenomenon of abnormal noise of wheel loader engine is often related to the speed of the engine, the load accepted by the engine, the temperature of the engine, and the oil circulation pipe of the engine, so when checking the cause of the abnormal noise of the loader engine, it can be based on the location of the abnormal noise. Come look further?
1 The abnormal sound of loader engine "connection with excavator load"
. The abnormal noise appears when a cylinder of the engine is misfired, and will disappear after a while. The reason may be because the engine piston knocks on the cylinder, or because the connecting rod bearing is loose, or the piston ring leaks.
The abnormal noise appears when a cylinder of the engine is misfired, but the abnormal noise is getting louder, it may be because: the copper sleeve of the piston pin is loose, the taper of the piston skirt is too large, the piston pin comes out, and the connecting rod bearing cover The fixing bolts have been loosened or the connecting rod bearing alloy has been melted and removed, etc.
. If it is a continuous fire of two cylinders adjacent to the engine, the abnormal noise of the Carter loader engine may be displayed: the crankshaft bearing is loose.
2 Reasons for abnormal noise of loader engine "Relationship with engine speed"
The abnormal noise of the engine is displayed at idle or low speed. Generally, the reasons for the presentation are: the gap between the piston and the cylinder wall of the Carter loader engine is too large, or the piston pin device is too tight, or the Carter loader engine. The gap between the tappet and the guide hole is too large, etc.
. The abnormal noise of the Carter loader engine appears at a certain speed, which may be due to: the engine crankshaft is broken, the piston pin bush is loose, or the camshaft timing gear of the engine is broken or the fixing nut is loose.
The abnormal noise appears when the engine of the Caterpillar loader accelerates rapidly, which may be due to the following reasons: the connecting rod bearing is loose, the bearing bush is melted or the size is not consistent and rolling, the crankshaft bearing is loose or the bearing bush is burned, the piston pin is broken, the crankshaft is broken and many more.
malfunction repair:
3. After disassembly, it was found that the rocker arm of the exhaust valve of the third cylinder was cracked, the upper half of the valve push rod was broken, the valve lock was damaged, and the valve fell into the cylinder. After removing the cylinder head, it was found to fall into the row of the third cylinder The valve rod is stuck on the exhaust valve seat ring, and the valve head in the falling cylinder bumps the top of the third cylinder piston.
4 "The connection with temperature" of the abnormal sound of the loader engine
. Low temperature abnormal noise, the abnormal noise gradually disappears after the temperature rises. The reason for the abnormal noise of the Carter loader engine is: the gap between the piston and the cylinder wall is too large, or the engine oil pressure is low and smooth is not good.
High-temperature abnormal sound, the abnormal sound disappears as the temperature decreases. The reason for the abnormal noise of the Carter loader engine is: the piston of the Carter loader engine is deformed, or the gap between the piston rings is too small, and it may be caused by pre-ignition caused by overheating. .
5.Update the third cylinder exhaust valve, exhaust valve seat ring, valve lock plate, valve oil seal, valve spring, valve push rod and rocker arm, etc., and reinvent the third cylinder exhaust valve seat. Repair the damaged part of the piston top. Then carry out the correct device and commissioning, and prepare to start the test machine.
6. However, in the process of driving the diesel engine with the starter motor, I still heard a "click, click" knocking sound inside the diesel engine. After several starts, this is the case. At first, I thought that it may be that the top of the piston was not trimmed. Thoroughly, the margin of the head of the exhaust valve collided with the margin of the pit on the top of the piston, and the abnormal noise was announced. For this, the cylinder head was removed, and the top of the piston of the third cylinder was completely repaired. There is still a "tap, tap" sound inside the diesel engine.
7. When using the starter motor to drive the diesel engine to roll, carefully observe the movement of the valve rocker arm. When it is found that the rocker head of the exhaust cylinder of the third cylinder has just pressed the valve, the "click, click" sound inside the diesel engine will follow. It can be seen that the abnormal noise is not caused by the exhaust valve colliding with the piston. This is because the piston is at the position close to the bottom dead center. Further judgment, the problem may be between the camshaft and the tappet.
8. Remove the diesel engine puncture gear chamber cover, at the same time remove the oil pan and the fourth cylinder inlet and exhaust valve tappet, the third cylinder intake valve tappet. Then pull out the camshaft, the third cylinder cracked The bottom of the tappet falls naturally.
9.Remove the cylinder head, when the third cylinder exhaust valve tappet is taken up, the tappet has only a cylindrical object, and its bottom is left between the cam and the cylinder block duct.It is obvious that the internal The sound of "tap, tap" is due to the collision sound announced during the movement of the bottom of the tappet after cracking.
10.Replace a new valve lifter and adjust the valve clearance to test the machine.The abnormal noise inside the diesel engine is eliminated and everything is normal.
