Pic. 54. Piston and connecting rod after disassembly: 1 - piston rings; 2 — lock rings of a piston pin; 3 - piston; 4 - piston pin; 5 - connecting rod; 6 - bearing sleeve in the upper head of the connecting rod; 7 — bolts of fastening of a cover of a rod bearing; 8 - the upper shell of the connecting rod bearing; 9 - lower shell of the connecting rod bearing; 10 - connecting rod bearing cap
On fig. 54 shows individual parts of a piston with a connecting rod. When assembling and installing them, you must perform the following operations:
- before assembly, carefully inspect the surfaces of the pistons (if new pistons are installed). Check the diameters, size groups and the last two digits according to the spare parts catalog, which must be indicated on the pistons and meet the installation requirements;
- when replacing connecting rods, pay attention to the lower parts of the bearing caps, where one or two dot marks can be punched, which determine the size group of the bearing shells;
Pic. 63. Piston with connecting rod assembly
- lubricate the piston pin and press it into the holes of the piston bosses and connecting rod bushings with a suitable mandrel. Install piston pin circlips on both sides, making sure they are well seated in their grooves. Install the piston with the connecting rod in the engine in such a way that arrow 1 (pic. 63) on the bottom of the piston pointed to the front of the engine, and the guide petals 2 of the connecting rod bearing shells were located on the left side of the engine;
- make sure that after assembly the piston turns freely in both directions on the piston pin;
Pic. 64. Piston rings in the context: 1 - composite oil scraper ring with expander (work surface chrome-plated); 2 - lower compression ring with a cross section in the form of a trapezoid; 3 - top compression ring of square section (contact surface asymmetrically ground and chrome-plated)
- Using piston ring pliers, install the rings on the piston, paying special attention to the correct sequence of their installation. Compression rings can be easily mixed up, so pay attention to their sections and location on the piston. On fig. 64 shows the sections of the rings and the order of their location.