8981706171 Excavator Spare Parts 4HK1 Engine Cylinder Head 

The original cylinder head of the Isuzu 4HK1 engine, with a common part number of 8981706171 (also commonly referred to as 8-98170617-1), is a core component designed specifically for the 4HK1 series diesel engines. This cylinder head is mainly suitable for Hitachi brand excavators equipped with 4HK1 engines, such as the ZX240-3 model. Meanwhile, it is also widely applicable to other construction machinery using Isuzu 4HK1 engine
 

The cylinder head is made of high-strength alloy cast iron or high-quality aluminum alloy casting, which has excellent heat resistance, creep resistance, and mechanical strength. It is internally integrated with precision intake and exhaust passages, cooling water jackets, lubricating oil passages, as well as valve guides and valve seat ring mounting holes. The standard dimensions are approximately 667mm in length, 279mm in width, and 172mm in height. As a key component of the 4HK1 engine (displacement 5.2 liters, inline four cylinders, 16 valves), it is responsible for sealing the upper part of the cylinder, forming the combustion chamber together with the piston and cylinder wall, and carrying the valve train (camshaft, rocker arm, etc.).
 

The installation and maintenance of the cylinder head must strictly follow the specifications. Before installation, the joint surface between the cylinder head and cylinder block must be thoroughly cleaned to ensure no oil stains, carbon deposits, or impurities, and the flatness must be checked. When replacing the cylinder gasket, attention should be paid to its installation direction (usually with the rolled edge facing the easily adjustable surface or installed according to the markings). Tightening the cylinder head bolts is crucial, and qualified bolts must be used and tightened 2-4 times to the specified torque in the order specified by the manufacturer (usually diagonally crossing from the middle to both sides). For cast iron cylinder heads, secondary tightening is required after the engine is warmed up. After installation, it is necessary to check the sealing of the cooling system and adjust the valve clearance. Regular maintenance should check the cylinder head for cracks, deformation, or corrosion, and keep the coolant clean to prevent scale and corrosion.