1) Connecting rod small end
The structural shape of the small end depends on the size of the piston pin and how it is connected to the small end of the connecting rod.

2) Connecting rod shaft
The section of the shaft is I-shaped, with high rigidity, light weight and suitable for die forging. The Y-Y axis of the I-shaped section is in the moving plane of the connecting rod. Some connecting rods have oil passages processed in the rod body to lubricate the small head bushing or cool the piston. If it is the latter, an oil injection hole must be processed on the top of the small head.

3) Big end of connecting rod
In addition to sufficient rigidity, the big end of the connecting rod should also be small in size and light in weight, and can be taken out from the upper end of the cylinder when the engine is disassembled. The big end of the connecting rod is split, and the connecting rod cover is fastened with bolts or studs. In order to make the joint surface tightly combined at any speed, the tightening torque of the connecting rod bolts must be large enough.

4) Connecting rod bolts
The connecting rod bolts are subjected to alternating loads during work, so the elasticity of the connecting rod bolts should be increased as much as possible in the structure, and the transition fillets should be finely processed in processing to eliminate stress concentration and improve its fatigue resistance. The connecting rod bolts are made of high-quality alloy steel, such as 40Cr, 35CrMo, etc. After quenching and tempering, the thread is rolled, and the surface is treated with antirust.

1) Bitzer 4NC piston kit top

The shape of the top of the gasoline engine piston is related to the shape of the combustion chamber and the size of the compression ratio. Most gasoline engines use flat-top pistons, which have the advantages of small heating area and simple processing. With a concave top piston, the compression ratio of the engine can be adjusted by changing the size of the pit on the top of the piston.

2) Bitzer 4NC piston kit head

The part from the top of the piston to the lower end surface of the oil ring groove is called the piston head. Gas ring grooves and oil ring grooves for installing gas rings and oil rings are processed on the piston head. An oil return hole or a transverse groove is also processed at the bottom of the oil ring groove. The excess oil scraped by the oil ring from the cylinder wall flows back to the oil pan through the oil return hole or the transverse groove. The piston head should be thick enough, the section change from the piston top to the ring groove area should be as smooth as possible, and the transition fillet R should be large enough to reduce the heat flow resistance, so that heat can be transferred from the piston top to the cylinder wall through the piston ring, so that The temperature at the top of the piston is not too high. The role of setting a narrow heat insulation groove above the first gas ring groove is to cut off the heat flow from the piston top to the first piston ring, so that part of the heat can be transmitted from the second and third piston rings, so as to reduce the heat loss. The heat load of the first piston ring improves its working conditions and prevents the piston ring from sticking.

3) Bitzer 4NC piston kit skirt

The part below the head of Bitzer 4NC piston kit is the piston skirt. The shape of the skirt should ensure that the piston is well guided in the cylinder, and a uniform and suitable clearance should be maintained between the cylinder and the piston under any working conditions. If the gap is too large, the piston will knock on the cylinder; if the gap is too small, the piston may be stuck by the cylinder. In addition, the skirt should have sufficient practical bearing area to withstand lateral forces. The side of the piston skirt that bears the expansion lateral force is called the primary thrust surface, and the side that bears the compression lateral force is called the secondary thrust surface.