老机手在安装新活塞环前,总是不厌其烦地将活塞环一道一道地放在离缸筒上平面25～30毫米处,用活塞顶平后观察其开口间隙大小。有的机手粗心大意,不检查或只检查一两道气环就不检查了,结果真出了问题。我遇到一台机子出现活塞接近下止点时曲轴不能转动的故障,经询问和拆检,就是因两道油环 Before installing the new piston ring, the old man always took the trouble to put the piston rings together in a plane 25-30 mm away from the cylinder tube. After checking the clearance of the opening with the piston top flat. Some machine guards carelessness, do not check or check only one or two air rings do not check, the result is a real problem. I encountered a loom piston appears near the bottom dead center can not rotate the crankshaft fault, after asking and dismantling, it is because of the two oil rings