8973767192 Excavator Engine Parts Valve Guide for 4HK1

This component is the core part of the valve train of the 4HK1 series diesel engine, used to accurately guide the up and down movement of the valve stem and transfer heat from the valve head to the cylinder head. Its universal model covers all Hitachi medium-sized excavators equipped with 4HK1 engines, such as ZX200-3, ZX240-3, ZX210LC-3, etc., and is also applicable to other brands of equipment using the same engine. As an original precision component, its inner diameter, outer diameter, length, and material form a precision friction pair with the cylinder head guide hole and valve stem. It is strictly prohibited to use accessory parts that do not match the size or material, otherwise it will result in abnormal oil consumption, poor valve sealing, or decreased engine power.

This product is a powder metallurgy (PM) material valve guide, which is a precision cylindrical shape in dark gray. Made by pressing and sintering iron-based powder mixed with copper, graphite and other elements, it has a uniform micro pore structure that can adsorb and store a small amount of engine oil, achieving excellent self-lubricating performance. It has high surface hardness, excellent wear resistance, and good thermal conductivity, which can effectively transfer valve heat to the cylinder head. Typical technical parameters include: strict control of inner diameter tolerance at H7 level, appropriate interference fit of outer diameter design to ensure firm press fit with cylinder head hole, and working temperature up to 300 ℃ or above.

Installation specifications (extremely critical): 1 Testing: Before installation, it is necessary to use an inner diameter dial gauge and an outer diameter micrometer to measure the inner and outer diameters of the new and old pipes, as well as the size of the cylinder head pipe hole, to confirm the fit interference (usually 0.02-0.05mm). 2. Cleaning and Cooling: Thoroughly clean the cylinder head conduit holes and place the cylinder head in a refrigerator or liquid nitrogen to cool and shrink, or heat the new conduit appropriately to reduce pressure resistance during installation. 3. Press fit: A dedicated stepped core shaft and hydraulic press must be used to ensure that the conduit is absolutely vertical and smoothly pressed into place. After pressing, it is necessary to use a reamer or diamond reamer to precision machine the inner hole of the guide tube to the final size and ensure its coaxiality with the valve seat.