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Complete cylinder head solution for high‑power diesel engines – The OEM D30-1003170K Cylinder Head Assembly is a factory‑matched, fully assembled unit designed for SINOTRUK Homan heavy‑duty diesel engines. Featuring high-strength cast iron construction, press‑fit valve guides, and hardened seats, this assembly ensures perfect sealing, efficient combustion, and extended service life under extreme thermal and mechanical stress. For guaranteed compatibility and performance, always choose genuine Sinotruk Homan parts.
The D30-1003170K cylinder head assembly includes the bare cast iron head, four valves per cylinder, valve springs, keepers, valve stem seals, rocker arm pedestals, injector sleeves, and glow plugs (where applicable). It is ready to bolt onto the engine block with only the rocker arms and fuel injection lines requiring final installation. This assembly eliminates the need for time‑consuming component‑by‑component head rebuilds, reducing downtime.
The D30-1003170K cylinder head is cast from high‑alloy grey iron with improved thermal fatigue resistance and high tensile strength. The combustion deck is precision milled to a flatness tolerance of 0.05 mm, ensuring an excellent seal with the head gasket. Valve seats are induction‑hardened and pressed to depth, then finish‑ground to a 45‑degree sealing angle for leak‑tight closure.
This assembly is designed for SINOTRUK Homan D10 and D12 diesel engines used in HOWO, A7, T7H and C7H trucks. Each unit is pressure‑tested to 8 bar to verify water jacket integrity and valve seat sealing. The factory assembly includes precision valve lash adjustment, saving workshop time and eliminating errors.
The valve guides are made from powdered metal with self‑lubricating properties, reducing wear and oil consumption. Intake and exhaust valves are forged from 21‑4N heat‑resistant steel and chrome‑plated on the stem to resist galling. Valve springs are shot‑peened for fatigue resistance and are tested to withstand 5 million cycles without sag.
Complete with valves, springs, guides, seats, and injector sleeves. The D30-1003170K bolts directly to the block.
Alloy iron casting with optimized water jacket flow and multi‑layer steel (MLS) head gasket compatibility. Operates reliably up to 450°C exhaust gas temperature.
Cylinder head face flatness ≤0.05 mm, valve seat concentricity ≤0.03 mm. No additional surfacing required before installation.
| OEM Number | D30-1003170K |
| Product Name | Cylinder Head Assembly (Complete with valves, springs, guides, seats) |
| Brand | SINOTRUK Homan |
| Material | High‑alloy grey cast iron (EN‑GJL‑250 equivalent) |
| Number of Valves | 4 valves per cylinder (2 intake, 2 exhaust) |
| Valve Stem Diameter | 8 mm (intake and exhaust) |
| Valve Seat Angle | 45° (intake) / 45° (exhaust) |
| Valve Spring Free Length | 52.5 mm ± 0.5 mm |
| Valve Spring Force (installed) | 280 N (intake) / 320 N (exhaust) |
| Combustion Chamber Volume | 72.5 cc ± 1.5 cc per cylinder |
| Head Gasket Surface Flatness | ≤ 0.05 mm across length, ≤ 0.03 mm per cylinder block |
| Maximum Re‑surfacing Limit | 0.30 mm (total material removal) |
| Cylinder Bore Compatibility | D10 (126 mm bore) and D12 (126 mm bore) |
| Injector Sleeve Type | Copper‑sealed, press‑fit, replaceable |
| Glow Plug Thread | M12 × 1.25 (if equipped) |
| Operating Temperature Range | -40°C to +120°C coolant, up to 800°C exhaust ports |
| Torque Specifications (head bolts) | 60 Nm + 180° + 180° (yield‑to‑torque procedure) |
| Applications | SINOTRUK HOWO, A7, T7H, C7H trucks with D10/D12 diesel engines |
| Compatible Models | D10.34, D12.38, D12.42, D12.46, and other D10/D12 series |
The D30-1003170K cylinder head is produced using advanced green‑sand casting and CNC machining. The casting process includes chill plates to promote directional solidification, reducing porosity in critical areas such as the fire deck and valve bridges. After machining, the head is subjected to a high‑pressure leak test (8 bar water pressure, 5 minutes hold) to verify water jacket integrity.
Valve seats are made from powder metal with high cobalt content for wear resistance at high temperatures. They are pressed into the head using liquid nitrogen cooling (‑196°C) and a hydraulic press, ensuring an interference fit of 0.08‑0.12 mm. After pressing, the seats are finish‑ground using CBN tooling to achieve a surface finish of Ra ≤ 0.4 μm and a concentricity of ≤ 0.03 mm relative to the valve guide bore.
Valve guides are made from sintered iron with a 0.2% graphite content for self‑lubrication. They are pressed into the head with an interference fit, then reamed to a final ID tolerance of +0.025/+0.035 mm. Each valve is lapped to its seat with a vacuum test to ensure leak‑tight sealing. The assembly includes valve stem seals (FKM rubber) that are colour‑coded (green for intake, brown for exhaust) to prevent mix‑ups.
The grey iron used for the D30-1003170K head has a tensile strength of 250 MPa minimum and contains fine flake graphite that dampens vibration and conducts heat away from the combustion chamber. The head is stress‑relieved after casting (550°C for 4 hours) to eliminate residual stresses that could cause cracking under thermal cycling. The valve seats are induction‑hardened to 55‑60 HRC to resist pounding from the valves.
The water jacket has been optimized via computational fluid dynamics (CFD) to ensure even cooling of the fire deck, especially around the valve bridges – a common failure point on other heads. Cooling passages also feature a ceramic coating on the water side to prevent cavitation erosion.
The D30-1003170K cylinder head assembly bolts directly onto the engine block using the original head bolts (new bolts must be used, as they are torque‑to‑yield). The assembly comes with the injector sleeves already pressed in and the glow plugs installed. Only the rocker arm assembly, pushrods, fuel injectors, and high‑pressure lines need to be transferred from the old head or supplied separately.
Before installation, verify that the block deck is clean and flat. Use a new multi‑layer steel (MLS) head gasket coated with sealing rubber. Follow the tightening sequence: from center outward, 60 Nm first pass, then 180° second pass, then final 180° third pass. After installation, allow the engine to cool, then re‑torque the head bolts (back off 90° then re‑torque to 60 Nm + 180°) only if specified by the manual.
1) Remove the old cylinder head, clean the block deck carefully. Use a straight edge and feeler gauge to check flatness (max 0.10 mm over length). 2) Install new head bolts (do not reuse old ones). Apply a light coat of engine oil to threads and under the bolt head.
3) Position the new MLS head gasket on the block, aligning with the dowel pins. 4) Install the D30-1003170K cylinder head assembly onto the gasket. 5) Install head bolts finger‑tight, then tighten in three stages according to the sequence: Stage 1: 60 Nm; Stage 2: 180° turn; Stage 3: final 180° turn.
6) Install the rocker arm assembly and set valve lash (intake: 0.30 mm, exhaust: 0.50 mm cold). 7) Connect fuel injectors and high‑pressure lines. 8) Fill coolant and engine oil. 9) Start engine and check for leaks. After the first operating cycle (engine fully warm to 85°C, let cool), recheck valve lash and re‑torque head bolts if required by the manual.
The D30-1003170K cylinder head assembly requires regular cooling system maintenance (use corrosion inhibitor) and timely oil changes. Common failure signs: coolant loss without external leaks (suggests cracked head or failed head gasket), white smoke from exhaust (coolant burning), and combustion gases in coolant (bubbles in radiator). If a head gasket failure occurs, always replace the cylinder head bolts and inspect the head flatness before reinstalling.
Do not apply more than 0.30 mm of resurfacing to the head, as this will affect valve timing and piston‑valve clearance. If a valve seat becomes damaged, the head can be rebuilt with new seats, but use only genuine SINOTRUK Homan parts. For severe overheating, replace the head assembly – hidden cracks may compromise reliability.
The D30-1003170K cylinder head assembly is manufactured under IATF 16949 and ISO 14001 certified systems. Each head is 100% inspected for porosity, flatness, valve seat concentricity, spring force, and valve stem seal fit. Random samples are subjected to thermal shock testing (alternating between ‑30°C and +120°C coolant for 500 cycles), high‑pressure impulse testing (10 bar water pressure pulses), and a 1000‑hour engine dynamometer test under full load.
The head meets SINOTRUK Homan engineering standard Q/SQ 1040 and SAE J1608 for diesel cylinder heads. A laser‑etched batch code and serial number on the head fire deck provide full traceability. Counterfeit heads often have poor casting finish, incorrect valve guide material, or lack the SINOTRUK Homan logo. Always purchase from authorised distributors and verify the QR code on the packaging.
A fleet of 250 SINOTRUK T7H trucks operating in long‑haul Australia replaced their original cylinder heads with the D30-1003170K assembly. After 1.2 million kilometers, none of the heads showed cracks or valve seat recession. Oil analysis showed low iron and aluminum wear metals, indicating good combustion sealing. Coolant consumption was negligible.
Another user – a mining contractor in South Africa – installed these heads on 180 HOWO dump trucks working in extreme dust and heat. After 800,000 km, the heads were removed for a planned overhaul; valve guides and seats were still within service limits. The fleet manager reported a 35% reduction in head‑related downtime compared to aftermarket rebuilt heads.
Each genuine D30-1003170K cylinder head assembly is packed in a heavy‑duty wooden crate with internal foam supports. The crate includes a SINOTRUK Homan hologram seal, a QR code, and a batch certificate. The head is covered with a protective anti‑rust oil film and plastic bag. The fire deck area has a laser‑etched OEM number and serial number. Counterfeit heads often have casting sand residue, uneven machining marks, or missing laser etching. Always scan the QR code to verify. Using a fake head can cause gasket failure, coolant loss, engine overheating, and catastrophic engine damage, voiding the warranty.
Summary: The SINOTRUK Homan Cylinder Head Assembly (OEM D30-1003170K) provides a complete, ready‑to‑install solution for D10/D12 diesel engines. With superior casting quality, precision‑machined valve train, and factory‑set valve clearances, this assembly ensures maximum engine performance and durability. Choose genuine for peace of mind and long service life.
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