The main points of piston ring installation are as follows: 　　 

1. Press-fit connecting rod copper sleeve. When installing the connecting rod copper sleeve, use a press as much as possible, or with the help of a vise, do not use a hammer to hit hard; the oil hole or oil groove on the copper sleeve and the oil hole on the connecting rod should be aligned to ensure its lubrication; After the sleeve is pressed in, the distance between the two ends of the connecting rod end face should be equal. 　　

2. Assemble the piston ring and connecting rod. When assembling the piston ring and connecting rod, pay attention to their relative position and direction. If the big end of the connecting rod is a flat cut, the vortex groove on the top of the piston should be on the same side as the big end of the connecting rod; if the big end of the connecting rod is an oblique cut, the vortex groove on the top of the piston should be on the same side as the upper end of the oblique cut. The top end of the piston should be pointed toward the fuel injection pump. 　　 

Three, cleverly installed piston pin. The piston pin and the pin hole are interference fit. During installation, the piston should be evenly heated to 90℃~100℃ in water or oil. After taking it out, put the pull rod in the appropriate position between the piston pin seat holes, and then install the piston pin coated with organic oil in the predetermined direction. Into the piston pin hole and the connecting rod copper sleeve. At the same time, push the piston pin while moving the connecting rod. Use your thumb or palm to slap into the pin hole and the copper sleeve of the connecting rod head, and move in it, indicating that the tightness of the two is suitable. To make the distance between the end face of the piston pin and the two piston pin retaining rings equal, install the retaining rings. 　　 Fourth, the installation of the piston ring. When installing piston rings, pay attention to the position and sequence of the rings. A gas ring on the piston is generally a chrome-plated ring. The second and third rings are mostly torsion rings, but there are also conical rings. If it is an inner cut ring, the cut should face downward; if it is a tapered ring, the side or taper angle engraved with the word "up" should face upward. The piston ring should not be stuck in the groove; the opening of a gas ring should not directly face the piston pin hole and the vortex groove on the piston top; the opening positions of adjacent rings should be staggered by 90 to 120 degrees to prevent gas leakage in the cylinder , To facilitate sealing. After the piston ring is installed, check its opening clearance (end clearance) and side clearance. If the opening gap is too large, it is easy to cause air leakage. If the gap is too small, it will cause jamming; the edge gap refers to the gap between the piston ring and the ring groove in height, which enables the ring to move freely in the ring groove without jamming. This gap should not be too large, otherwise, when the piston moves up and down in the cylinder, the gas ring will pump oil, and the lubricating oil will enter the combustion chamber, accelerating the consumption of lubricating oil and causing serious carbon deposits. 　　 

5. Install the connecting rod group. When the connecting rod is assembled into the cylinder, when installing the connecting rod cover, pay attention to the matching mark on the big end of the connecting rod. At the same time, use a torque wrench to tighten the bolts in 2~3 times according to the specified torque. Rotate the crankshaft without jamming, and then install the lock. Tighten the wire or fuse.