Dongfeng KL truck parts Cylinder assembly with liner process assembly 5003910-C3101

The integrated cylinder liner is crafted from centrifugally cast gray cast iron (HT300) with a pearlitic matrix and 20–25% graphite content—materials renowned for their exceptional wear resistance and heat conductivity. The liner’s inner surface undergoes a nitrocarburizing treatment (50–70μm case depth) that increases surface hardness to HV 800–1000, reducing wear from piston ring friction by 40% compared to untreated liners. It also features a honed crosshatch pattern (Ra 0.2–0.4μm surface roughness) that retains lubricating oil, forming a stable oil film between the liner and piston rings to minimize metal-to-metal contact. Unlike thin-walled liners that wear out within 300,000 km, this heavy-duty design ensures the liner endures 800,000+ km of operation, extending the engine’s overall service life and reducing maintenance frequency

Engineered to prevent coolant and oil leakage—critical for engine performance—the assembly integrates a multi-layer sealing system. The liner’s lower end features a copper gasket (1mm thickness) that compresses against the engine block’s water jacket, blocking coolant from seeping into the crankcase. The upper flange is equipped with a heat-resistant rubber O-ring (EPDM material, -40°C to 150°C temperature range) that seals the gap between the liner flange and engine block top deck, preventing oil leakage into the coolant passage. Additionally, the liner’s outer surface is coated with a high-temperature resistant sealant (capable of withstanding 250°C) during installation, further enhancing the seal between the liner and block. Unlike single-seal designs that fail under high temperature and pressure, this multi-layer system ensures zero leakage through 500,000+ km of engine operation

The cylinder assembly is designed to efficiently dissipate heat generated during engine combustion, preventing overheating and maintaining stable operating temperatures. The liner’s outer surface features spiral coolant grooves (2mm depth, 10mm pitch) that increase the contact area with coolant by 30%, accelerating heat transfer from the liner to the engine’s cooling system. The HT300 cast iron material’s thermal conductivity (55 W/m·K) ensures rapid heat conduction away from the combustion chamber, keeping the liner’s inner surface temperature below 280°C (critical for preventing piston ring sticking). The cylinder’s flange design also facilitates heat transfer to the cylinder head, balancing temperature distribution across the engine top end. Unlike liners with smooth outer surfaces that trap heat, this optimized design reduces engine operating temperature by 5–8°C under full load, improving fuel efficiency and reducing thermal stress on engine components

Each cylinder assembly undergoes strict quality testing to ensure reliability and compatibility with Dongfeng KL’s engine system. It passes a pressure test (3 MPa coolant pressure for 30 minutes) to verify sealing integrity, a dimensional inspection via coordinate measuring machine (CMM) to confirm precision, and a wear resistance test using a piston ring friction simulator. The assembly is fully compatible with the engine’s original piston (including piston skirt clearance of 0.15mm) and piston rings (ensuring proper ring seating), eliminating the need for component modifications. Installation requires only standard tools (e.g., hydraulic press for liner insertion, torque wrench for flange bolts) and follows the OEM service procedure, taking 2–3 hours per cylinder for professional technicians. Backed by a 24-month warranty against manufacturing defects (e.g., liner cracking, seal failure, dimensional inaccuracies), it provides Dongfeng KL truck owners with a reliable engine component that ensures consistent power output and long-term durability