Liner Kit Iran

LINER KIT

The piston pin bush is made from tin-phosphor bronze alloy comprising 80-90% copper, 8-12% tin, and 0.3-0.5% phosphorus. This alloy has a hardness between 80 and 100 Brinell. The internal diameter is manufactured to H7 dimensional tolerance with a surface finish of Ra 0.2 microns. Wall thickness varies from 1.5 to 3 mm depending on engine size. These bushes undergo precision machining followed by stress-relief heat treatment. Finally, their inner surface is machined with a cross or helical groove pattern 20-40 microns deep. These grooves increase oil retention capacity by up to 70%.

The bush features a monolithic one-piece design and structure. It is press-fitted into the piston boss with a minimum pressure of 15 MPa. The radial clearance between the bush and the piston pin ranges from 0.015 to 0.040 mm. Some advanced designs employ additional coatings like graphite on the inner surface. This coating reduces the friction coefficient to approximately 0.02. The designed service life under dynamic loading exceeds 5000 hours of continuous operation. This component can withstand surface pressures of up to 40 MPa.