4TNV94 Diesel Engine Cylinder Head Standard Size Excavator Machinery Parts

Excavator Parts Cylinder Head 4TNV94 Diesel Engine Parts Excavator Machinery Parts

Cylinder Head (Heavy-Duty Excavator Engine) The cylinder head is among the most critical heavy-duty precision parts of an engine. Mounted on the upper part of the cylinder block, it seals the cylinders, constitutes combustion chambers, integrates the valve train along with cooling and lubrication passages, and has a direct bearing on engine power, fuel efficiency and reliability. Core Functions Combustion Chamber Sealing: Closely attached to the cylinder block and cylinder head gasket, it bears 10–15 MPa of combustion pressure and high temperatures from 600 to 900 °C, preventing the leakage of air, water and oil. Valve Train Mounting Foundation: It holds valve seats, valve guides, intake and exhaust valves, valve springs, rocker arms and camshafts (overhead-cam type), controlling the timing of intake and exhaust strokes. Integrated Cooling and Lubrication: With internally cast water jackets for heat dissipation and oil galleries for lubricating valves and camshafts, it prevents thermal deformation and component wear. Fuel Injection Mounting Interface: The cylinder head of diesel engines is machined with injector mounting holes to guarantee the precise injection of high-pressure fuel into the combustion chamber. Common Faults Surface Distortion / Warpage: Resulting from overheating, uneven bolt tightness or damaged cylinder head gaskets, symptoms include air leakage, power reduction and high coolant temperature; grinding repair is needed when flatness is over 0.10 mm. Cracks: Cracks occur around water passages, oil galleries or valve seats, causing water, oil and air leakage; flaw detection is required, and severely cracked cylinder heads must be replaced. Valve Seat / Guide Wear: Long-term high-temperature impact causes seal failure, valve noise and oil consumption; replacement of seat inserts and guides as well as valve lapping is needed. Injector Bore Corrosion: Caused by fuel leakage and high-temperature gas erosion, it leads to poor sealing and insufficient power; repair by bushing or cylinder head replacement is necessary.

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