Bearing an engine there are many, whether or bush bush are all plain bearings. In order to guarantee running accuracy of the engine, these plain bearings running clearance requirements are very high. Cause engine bearing failure can be attributed to: lubricating critical state and any interference caused damage running clearance and the film of any material damage. Such as installation and adjustment is not accurate, there are parts bump damage and cleanliness poor, incorrect use of harmful chemical reaction will cause damage to the sliding bearings. According to the American Cummins Engine Failure Analysis statistics book, bearing damage caused by four main reasons. The percentage of these four areas accounted for the failure as follows:

1, the damage caused due to the cleanliness of 45%;

2, due to damage caused by lubrication is 25%;

3, due to the use of, damaged installation is 15%;

4, due to surface damage caused by the reaction and others 15%.

From the statistics, we can see that the ratio of the number of damage caused by the cleanliness of the bearing as the main reason. To prevent damage due to poor cleanliness of work are manifold: to ensure that only one aspect of cleanliness in parts of the engine assembly, on the other hand is the engine during use. Operators and maintenance staff must be used according to the provisions proper and timely maintenance checks, especially long-term work in dusty environments and chemical raw materials, engines, must take measures to prevent the erosion of dust and chemical fumes, ensure that the engine use life. Engine main bearing, connecting rod bearing surface layer of the softest alloy to withstand the maximum load, but also the most easily damaged, so following on the surface of the main bearing and connecting rod bearing damage phenomena, analyze the causes and to prevent recurrence after failover .

First, because of the cleanliness problems caused by the failure:

1, the small particles of foreign matter on the pad causing galling:

When the oil filter and engine oil pan drain plug, the first out of the tens of milliliters of oil, there is the naked eye can see and the more direct alloy powder, Bush had been galling. This is because tiny particles of impurities into the surface of the bearing alloy layer movement caused, although bearing no serious damage, but if such a phenomenon to continue, not only bearing early damage, the shaft will be severely damaged, it must be Depending on the cause promptly excluded, to avoid damage to parts. Troubleshooting engine bearing service life is not normal wear and tear of time calculation, because a small amount of abnormal wear particles equivalent to 2,500 hours of normal engine wear.

Reason tiny particles enter: First filtering effect of the difference between the air cleaner or air intake system seal is not good, the ministries to check the air intake system piping and connections, for cracks and loose, and check the filter loose, Zhixin Have rupture. Whether repair or maintenance of the entire intake system inspection is very important and must ensure reliability. Second, the lubricant added after being contaminated engine oil and filter, or prolonged use of all machine filter is clogged, then the oil lubrication surface without filtration directly into the filter. Third, excessive fuel oil combustion is incomplete, nozzle leakage, causing the fuel to penetrate the crankcase, while some impurities with the fuel into the crankcase and oil mixed together to reduce the lubricating effect. Therefore engine in use to observe the functioning of the engine exhaust and, if an exception to timely find out the reason for repair or replacement. Fourth, when the engine is assembled, cleanliness poor internal parts. When repairs and maintenance of the engine, must pay attention to clean parts of the installation should pay attention to prevent further contamination and to ensure the cleanliness of the interior after the installation.

Whatever the reason, the exclusion of the fault must replace the engine oil and engine filter. Repaired the engine starts idling two hours stopped for inspection, the oil no alloy powder can be put into use half load, but in the first few days of use must be observed, from 60 to 120 hours after the operation was completely abnormal wear judgment confirmed After removing, and then replace the oil, the engine can be put into normal use. If abnormal wear continues to develop, we must stop using the disintegration of inspection and repair.