The Valve train is a complex mechanical system that controls the opening and closing of the intake and exhaust valves in the HOWO 7 6X4 Dump Truck engine, ensuring efficient combustion and optimal power delivery. This assembly includes camshafts, push rods, rocker arms, springs, valves, and numerous fastening and sealing elements, all working in precise synchronization. For a complete listing of all valve train components and their specifications, refer to the Sinotruk Catalog which provides detailed cross-references and original equipment part numbers.
The Valve train set includes a wide range of components: Valve push rod assembly, Camshaft assembly, Valve cap (Reference drawing 161500050080), Valve rocker arm seat, Upper valve spring seat, Inlet valve, Exhaust valve, Camshaft thrust plate, Camshaft phasing gear, Valve tappet, Outer valve spring, Lower seat of intake valve spring, Inner valve spring, Valve lock clamp, Intake valve rocker arm, Exhaust valve rocker arm, Valve clearance adjusting screw, Valve clearance adjusting nut, Intermediate gear shaft, Intermediate gear gasket, Hexagon head bolt, Intermediate gear assembly, Baffle, Cover plate, Hexagonal flange face with toothed bolt, Hexagon bolt with flange, Sealing ring, Double-end stud-pre-coated locking, Hexagon nut with flange, Waveform spring washer, and Hexagon socket head cap screw-pre-coated locking layer.
The Valve train is engineered to operate at high speeds and temperatures, with each component designed to minimize friction and wear while maintaining precise valve timing. The camshaft drives the rocker arms via push rods and tappets, converting rotational motion into linear valve movement. Springs return the valves to their seats, and adjusting screws allow fine-tuning of clearance for optimal engine performance and longevity.
Regular maintenance of the Valve train is essential for engine efficiency and reliability. Worn tappets, springs, or valves can lead to power loss, increased emissions, and even catastrophic engine damage. Using genuine components ensures that the Valve train operates with the correct clearances and timing, preserving the engine’s performance and fuel economy over thousands of operating hours.
The Valve push rod assembly is a precision steel tube with hardened ends that transmits motion from the camshaft followers to the rocker arms. It is designed to maintain rigidity while being lightweight, reducing reciprocating mass. The push rod is hollow to allow oil flow to the rocker arm and valve train components, ensuring proper lubrication under all operating conditions.
The Camshaft assembly is a forged steel shaft with precisely ground lobes that operate the valve train. It is supported by journal bearings and driven by the crankshaft via gears or a timing chain. The cam profile determines valve lift, duration, and timing, directly affecting engine power and efficiency. This assembly includes the camshaft, timing gear, and thrust plate for axial location.
The Valve cap is a hardened steel disc that sits on top of the valve stem, providing a wear-resistant surface for the rocker arm contact. It also acts as a retainer for the valve spring and lock clamps. This cap is designed to withstand repeated impact loads while maintaining a precise fit on the valve stem, ensuring consistent valve operation.
The Valve rocker arm seat is a cast iron or aluminum pedestal that supports the rocker arm shaft and provides a pivot point for the rocker arms. It is bolted to the cylinder head and features precision-bored holes for the shaft. The seat ensures proper alignment of the rocker arms with the valve stems and push rods, enabling smooth and accurate valve actuation.
The Upper valve spring seat is a hardened steel washer that sits on the valve stem, supporting the upper end of the valve spring. It incorporates a groove or step to retain the valve lock clamps and provides a flat surface for the spring to bear against. This seat transfers spring force to the valve, ensuring proper sealing and preventing valve float at high rpm.
The Inlet valve is a poppet-style valve made from heat-resistant steel, with a slender stem and a large circular head that seals against the intake port. It opens to allow fresh air-fuel mixture into the cylinder and closes to maintain compression. The valve face is coated with a wear-resistant alloy to withstand the high temperatures and corrosive gases of the intake charge.
The Exhaust valve is similar to the inlet valve but is subjected to even higher thermal loads. It is made from a more heat-resistant alloy, often with a sodium-filled stem for better heat transfer. The valve opens to release spent gases from the cylinder, and its seat must be durable enough to resist erosion and sealing degradation over thousands of cycles.
The Camshaft thrust plate is a flat steel plate that limits the axial movement of the camshaft within the engine block. It is bolted to the front of the block and features a hardened surface that contacts the camshaft gear or flange. This plate ensures consistent camshaft timing by preventing end-play that could alter valve opening events.
The Camshaft phasing gear is a precision-toothed wheel that connects the camshaft to the crankshaft via a chain or belt. It ensures exact timing between the camshaft and crankshaft, with keyways or splines for accurate positioning. This gear is hardened and ground to minimize wear and maintain precise valve timing throughout the engine’s life.
The Valve tappet is a cylindrical plunger that rides on the camshaft lobe and transfers motion to the push rod. It is made from chilled iron or steel and is case-hardened to resist wear. Some tappets are hydraulic, using oil pressure to automatically adjust valve clearance, while others are solid and require manual adjustment. This tappet ensures smooth and quiet valve operation.
The Outer valve spring is a large-diameter coil spring that surrounds the inner spring to provide additional closing force for the valve. It is made from high-tensile spring steel and is designed to maintain consistent pressure even at high engine speeds. This spring prevents valve bounce and ensures that the valve follows the cam profile accurately.
The Lower seat of intake valve spring is a hardened steel ring that supports the bottom of the valve spring on the cylinder head. It fits into a recess in the head and provides a stable platform for the spring, ensuring that the spring force is transmitted evenly to the valve seat. This seat also helps to position the valve stem seal.
The Inner valve spring is a smaller-diameter spring located inside the outer spring, working in parallel to increase the total closing force without increasing spring height. This dual-spring design provides a higher natural frequency, reducing the risk of valve float at high rpm while maintaining manageable stress levels on each spring.
The Valve lock clamp is a pair of conical steel collets that fit into a groove on the valve stem and are retained by the valve spring seat. They securely lock the valve spring to the valve, transferring the spring load and preventing the valve from dropping into the cylinder. These clamps are hardened and precision-ground for a secure, vibration-resistant fit.
The Intake valve rocker arm is a forged steel lever that pivots on a shaft, transmitting motion from the push rod to the intake valve. It features a roller tip or a hardened pad that contacts the valve cap, reducing friction and wear. The rocker arm ratio determines valve lift, and its geometry is carefully designed to maintain proper valve train dynamics.
The Exhaust valve rocker arm is similar to the intake rocker but is designed to withstand higher exhaust temperatures. It often includes an oil passage for cooling and lubrication, and its pivot and contact surfaces are hardened to resist wear from the hot exhaust valve. This rocker ensures precise exhaust valve timing and sealing under extreme conditions.
The Valve clearance adjusting screw is a threaded bolt located on the rocker arm that allows precise adjustment of the clearance between the rocker tip and the valve stem. It has a rounded or flat tip that contacts the valve cap, and it is locked in place with a lock nut. This screw enables fine-tuning of valve lash to compensate for thermal expansion and wear.
The Valve clearance adjusting nut is a hexagon lock nut that secures the valve clearance adjusting screw in its set position after adjustment. It is made from steel and often features a nylon insert or distorted thread to prevent loosening due to vibration. Proper torque on this nut is critical to maintain the preset valve lash and ensure consistent engine performance.
The Intermediate gear shaft is a hardened steel axle that supports the intermediate gear in the camshaft drive system. It is pressed or bolted into the cylinder block and provides a precise pivot for the gear, ensuring accurate timing transfer between the crankshaft and camshaft. The shaft is oil-lubricated to reduce wear on its bearings.
The Intermediate gear gasket is a thin paper or composite gasket that seals the interface between the intermediate gear cover and the cylinder block. It prevents oil leaks from the gear chamber and maintains proper pressure within the lubrication system. This gasket is cut to match the cover shape and is replaceable during maintenance.
The Hexagon head bolt is a standard metric bolt with a six-sided head, used to secure various valve train covers, brackets, and supports. It is made from medium-carbon steel and is available in different grades for load requirements. These bolts are used in conjunction with washers or lock nuts to prevent loosening under vibration.
The Intermediate gear assembly consists of a toothed gear mounted on a hub, with internal splines or a keyway for connection to the intermediate shaft. It transmits rotation from the crankshaft gear to the camshaft gear, maintaining correct timing. This assembly is precision-machined for silent operation and includes a thrust washer to control axial play.
The Baffle is a sheet metal plate that deflects oil splashing from the camshaft and valve train, helping to direct oil flow back to the sump and preventing excessive oil mist from reaching the intake system. It also acts as a shield to protect the timing chain or gears from debris, contributing to cleaner engine oil and longer component life.
The Cover plate is a stamped steel or aluminum panel that closes an access hole in the valve train area, preventing dirt ingress and containing oil splash. It is secured with bolts and often includes a gasket or sealant for oil-tight sealing. This plate may also provide mounting points for sensors or brackets.
The Hexagonal flange face with toothed bolt is a specialized fastener that features a serrated bearing surface under the head, which provides a locking action against the mating part. The flange distributes load and eliminates the need for a separate washer. This bolt is used in high-vibration areas of the valve train to prevent loosening.
The Hexagon bolt with flange is a common fastener with an integrated circular flange that acts as a washer, increasing the bearing area and reducing the risk of galling on soft materials. It is used for mounting various valve train components, providing a secure and vibration-resistant connection.
The Sealing ring is an O-ring or shaped elastomeric seal used to prevent oil or coolant leaks at joints in the valve train area. It is made from oil-resistant synthetic rubber and is designed to withstand high temperatures and pressures. These rings are found around camshaft bearing caps, cover plates, and oil passages.
The Double-end stud-pre-coated locking is a threaded rod with threads on both ends, coated with a micro-encapsulated adhesive that provides locking action when tightened. It is used for mounting components where a bolt cannot be used, and the pre-coated layer ensures consistent clamp load and resistance to vibration-induced loosening.
The Hexagon nut with flange is a standard hex nut with an integrated washer-like flange that spreads the load and provides a smooth bearing surface. It is used with bolts to fasten valve train components, and the flange eliminates the need for a separate washer, simplifying assembly and reducing parts count.
The Waveform spring washer is a wavy steel washer that provides a spring-like preload between bolted joints, compensating for thermal expansion and preventing loosening. It is used in valve train applications where maintaining bolt tension is critical, such as on camshaft bearing caps.
This screw features a hexagon socket drive and is pre-coated with a locking compound that cures after installation, providing a secure, vibration-resistant connection. It is used in confined spaces where a standard bolt cannot be accessed, and the locking layer eliminates the need for liquid thread-locker during assembly.
| No. | Part No. | Description |
|---|---|---|
| 1 | VG1092050020 | Valve push rod assembly |
| 2 | VG1500050097A | Camshaft assembly |
| 3 | VG1500050105 | Valve cap (Reference drawing 161500050080) |
| 4 | VG14050119 | Valve rocker arm seat |
| 5 | VG1500050109 | Upper valve spring seat |
| 6 | VG1560051001 | Inlet valve |
| 7 | VG1560050041 | Exhaust valve |
| 8 | VG14050133 | Camshaft thrust plate |
| 8 | VG14050503 | Camshaft phasing gear |
| 9 | VG1500050032 | Valve tappet |
| 11 | VG1500050002 | Outer valve spring |
| 12 | VG14050017 | Lower seat of intake valve spring |
| 13 | VG1500050001 | Inner valve spring |
| 14 | VG1500050025 | Valve lock clamp |
| 15 | VG14050048 | Intake valve rocker arm |
| 16 | VG14050049 | Exhaust valve rocker arm |
| 17 | VG14050010 | Valve clearance adjusting screw |
| 18 | VG2130050065 | Valve clearance adjusting nut |
| 19 | VG1540059031 | Intermediate gear shaft |
| 20 | VG1540059032 | Intermediate gear gasket |
| 21 | VG1560050059 | Hexagon head bolt |
| 22 | VG1560050053 | Intermediate gear assembly (Reference drawing 161560050052) |
| 23 | VG1560050045 | Baffle |
| 24 | VG1560050046A | Cover plate |
| 25 | Q1800816TF2 | Hexagonal flange face with toothed bolt |
| 26 | Q1860822TF2 | Hexagon bolt with flange |
| 27 | Q150B1260TF2 | Hexagon head bolt |
| 28 | 1.90003E+11 | Sealing ring |
| 29 | Q1200816S | Double-end stud-pre-coated locking |
| 30 | Q32008 | Hexagon nut with flange |
| 31 | Q41808 | Waveform spring washer |
| 32 | Q218B0816S | Hexagon socket head cap screw-pre-coated locking layer |
OEM-grade materials and precision engineering. Our Valve train components are manufactured from premium steel alloys and castings, with heat treatment and surface coatings that match original specifications. This ensures long-term durability and resistance to wear, even under the high temperatures and cyclic stresses of heavy-duty engine operation.
Complete kit with all fastening and sealing elements. Our Valve train set includes not only the major actuating parts but also every bolt, nut, washer, gasket, and sealing ring needed for a full overhaul. This saves time and ensures that nothing is overlooked during reassembly, resulting in a leak-free and precisely adjusted valve train.
Advanced surface treatments for reduced friction and wear. Our camshafts, tappets, and rocker arms feature specialized coatings such as DLC or phosphate, which minimize friction and oil shearing. This translates to improved fuel efficiency, reduced operating temperatures, and extended component life in the demanding environment of a dump truck.
Trusted by professional rebuilders and fleets worldwide. Our Valve train components are used by major engine overhaul facilities and fleet maintenance shops, who rely on the consistent quality and precise fit of our products. By choosing our Valve train, you ensure that your HOWO 7 6X4 engine delivers maximum power and reliability for countless miles.
Our online catalog provides comprehensive access to genuine SINOTRUK parts for all major vehicle lines — including HOWO, Sitrak, Steyr, and Yellow River series trucks. You can browse detailed specifications, original part numbers, and exploded-view diagrams for every assembly. Whether you are performing routine maintenance or planning a major overhaul, the catalog helps you quickly identify the correct components for your vehicle. When you become a SINOTRUK customer, we offer complimentary full‑access catalog services, ensuring you always have the latest product data and interchangeability information at your fingertips to support efficient fleet management and accurate parts ordering.
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