一台刚大修过的EQ140发动机在冷磨热试的时候,发出一种“当、当”的有规律的金属敲击声。用金属杆听诊,响声在中下部,经断火试验并不上缸,响声频率随发动机转速加快而提高。打开油底壳检查,开始并没发现有什么异常现象,因而故障未能立即排除。后经仔细查找,发现四缸靠里边的连杆螺栓头横了过来,未能进入连杆螺栓槽的正确位置,且 A newly overhauled EQ140 engine emits a “when, when” regular metal percussion sound during a cold mill heat test. Auscultation with a metal rod, the sound in the lower part, the test is not off the fire cylinder, the sound frequency increases with the engine speed and speed up. Open the oil pan inspection, the beginning did not find any anomalies, and failure can not be ruled out immediately. After careful search and found that four-cylinder by the inside of the connecting rod bolt horizontal cross over, failed to enter the connecting rod bolt groove the correct position, and