CAT 8N-2275 Sleeve Bearing Bushing

CAT 8N-2275 is a Caterpillar genuine steel-backed bronze piston pin bushing bearing, suitable for the small end of the connecting rod in D379/D398/D399 series engines. It provides low-friction support for the piston pin and connecting rod, withstands reciprocating impact loads, and ensures precise piston and connecting rod oscillation. The following are the professional parameters and application guidelines:

Core Technical Parameters (Professional Version)

Item Details
Basic Attributes
Model: 8N-2275; Type: Steel-backed bronze piston pin bushing bearing; Suitable for the small end of the connecting rod in Cat D379/D398/D399 engines, D9H tracked bulldozers, 594H pipelaying machines, etc.; Material: Steel backing + bronze alloy (CuSn8P, oil-lubricated); Inner diameter: φ68.07 mm; Outer diameter: φ76.2 mm; Length: 57.15 mm; Weight: Approximately 0.3 kg; Operating temperature: -20℃ to + 220℃, suitable piston pin diameter φ68 mm, press-fit interference 0.08-0.12 mm, suitable clearance 0.015-0.025 mm (boring/honing after installation)

Key Dimensions: Inner diameter tolerance 0/+0.010 mm, outer diameter tolerance 0/-0.015 mm, length tolerance ±0.1 mm, wall thickness 3.965 mm, steel backing thickness 1.2 mm, bronze layer thickness 2.765 mm, chamfer at both ends 1×45°, suitable connecting rod small end bore diameter φ76.2 mm (tolerance H7), piston pin mating clearance 0.015-0.025 mm, surface roughness Ra≤0.8 μm

Material and Process: Steel backing is low carbon steel (SPCC, thickness 1.2 mm), bronze alloy layer is CuSn8P (containing 8% tin, 0.3% phosphorus, hardness HB) (80-100), composite molding using sintering process, bronze layer with oil porosity of 15%-20% (self-lubricating), surface honed (roughness Ra≤0.8 μm), deburred at both ends, free of porosity/slag inclusions, suitable for reciprocating loads ≤15 kN and oscillation frequencies ≤10 Hz.

Compatible models: Cat D379/D398/D399 industrial/marine engines, D9H tracked bulldozers, 594H pipelaying machines, G379/G398/G399 generator sets. The core component provides low-friction support for the connecting rod small end and piston pin, absorbing reciprocating impact loads, preventing dry friction wear between the piston pin and connecting rod, and ensuring piston movement accuracy and connecting rod oscillation stability.

Assembly fit: Interference fit with connecting rod small end (interference 0.08-0.12 mm), clearance fit with piston pin (clearance 0.015-0.025 mm). (After installation, it needs to be boring/honed to the target clearance). After installation, check the inner diameter roundness ≤ 0.005 mm, cylindricity ≤ 0.01 mm, and parallelism of both end faces ≤ 0.01 mm.

Installation and Maintenance Points:

Before installation, clean the connecting rod small end bore, sleeve bearing, and piston pin. Check the bearing for cracks/delamination/rust, and ensure the connecting rod bore is undamaged. Measure the bore diameter to confirm the interference fit meets requirements.

During assembly, use a special press to press the bearing in at a uniform speed (avoiding misalignment). After pressing, bore/hon the inner diameter to the target clearance of 0.015-0.025 mm. Finally, clean off any remaining chips, apply engine oil, and install the piston pin.

Maintenance Recommendation: Check the clearance between the piston pin and bearing every 2000 hours. Replace immediately if the clearance exceeds 0.05 mm to prevent the piston pin from loosening and causing wear or breakage of the connecting rod small end.