Cummins engine spare parts piston pin C4389340 in stocked

Crafted from 20CrMnTi alloy steel—a premium material for high-stress engine components—the piston pin delivers exceptional mechanical performance tailored to reciprocating motion. This material undergoes a rigorous heat treatment process: carburizing at 920°C (to a depth of 0.8–1.2mm), quenching at 850°C, and tempering at 200°C—resulting in a surface hardness of 58–62 HRC (wear resistance) and a core hardness of 30–35 HRC (toughness to resist impact). It exhibits a minimum tensile strength of 1,100 MPa and yield strength of 850 MPa, enabling it to withstand the cyclic loads of up to 150 MPa generated during engine combustion (equivalent to 4,000 RPM full-load operation). Compared to standard carbon steel pins, 20CrMnTi alloy steel reduces the risk of pin bending or fracture by 70% under extreme conditions, extending service life to 300,000 km (typical for Cummins ISF engines)

The piston pin features ultra-high-precision machining across all critical surfaces to ensure stable reciprocating motion and minimal friction:

Outer Surface: Ground to a surface finish of Ra ≤0.2μm (AGMA Class 12 precision) and a roundness tolerance of 0.002mm, ensuring even contact with the piston pin bushing and connecting rod small end bearing—reducing friction coefficient to ≤0.003 (critical for fuel efficiency).

Inner Bore: Honed to a surface finish of Ra ≤0.4μm and a concentricity tolerance of 0.005mm (relative to the outer surface), ensuring balanced weight distribution during high-speed reciprocation (preventing vibration-induced wear).

End Faces: Chamfered at 45° (0.5mm width) and deburred to eliminate sharp edges, which could scratch the piston pin boss or damage the engine oil film—critical for maintaining lubrication in the pin’s working area

To combat wear and corrosion in the engine’s lubricated environment (exposed to high-temperature oil and combustion byproducts), the piston pin undergoes two key surface treatments:

Phosphating: A zinc phosphate coating (8–12μm thick) applied to the entire surface, improving oil retention and preventing direct metal-to-metal contact during startup (when lubrication is insufficient).

Passivation: A post-phosphating passivation treatment that enhances corrosion resistance, ensuring the pin remains free from rust even during long-term storage (up to 24 months) or in humid environments (e.g., marine transport applications).

These treatments reduce the pin’s wear rate by 40% compared to uncoated alternatives and ensure compatibility with all Cummins-approved engine oils (SAE 5W-30 to 15W-40), eliminating the need for specialized lubricants

Designed for efficient installation by engine rebuilders and technicians, the piston pin simplifies assembly with user-friendly features and strict quality control:

No Special Tools Needed: The pin’s hollow design (weight of only 85g) and precise dimensions allow it to be pressed into the piston pin boss using standard hand tools (e.g., a hydraulic press with a 50kN capacity) or even manual pressure for light-duty applications—no specialized heating or cooling equipment required.

Clearance Verification: Each pin is laser-marked with its outer diameter tolerance (e.g., 38.002–38.004mm) for quick verification, ensuring technicians can match it to the correct piston and connecting rod without additional measuring.

Rigorous Testing: Every unit undergoes 100% inspection, including dimensional measurement via CMM (Coordinate Measuring Machine), hardness testing (using a Vickers hardness tester), and magnetic particle inspection (to detect internal cracks).

Installation typically takes 15–20 minutes per cylinder: heat the piston to 80–100°C (to expand the pin boss), insert the pin through the piston and connecting rod small end, and install the retaining clips (included with the pin). Backed by a 24-month OEM warranty against defects (e.g., wear beyond specification, bending, surface cracking), it ensures reliable performance throughout the engine’s service life