Buy Brand New Engine Head D1703 D1803 Cylinder Head Assy

Q1: What is the product identification and applicable scope of the brand-new D1703/D1803 cylinder head assy?

Core Product & Compatibility Details

1. Product Structure

   Delivered as a complete ready-to-install assembly, integrating precision-machined alloy cast iron casting, 6 valves (2 intake + 2 exhaust per cylinder), nickel-chromium alloy valve seats, powder metallurgy valve guides, injector mounting bores, integrated coolant passages, rocker arm pedestals, and pre-fitted sealing gaskets for critical joints.

2. Applicable Engines & Key Parameters

   Engine Model	Displacement	Rated Power	Key Features
   D1703	1.7L	24.8HP/18.5kW @ 2600rpm	Naturally aspirated, low fuel consumption, ideal for light-load operation
   D1803	1.8L	27.4HP/20.4kW @ 2600rpm	Enhanced torque output, suitable for medium-load scenarios
3. Matched Machinery & Working Scenarios
   • Construction Equipment: Kubota KX71-3, KX91-3 mini excavators; Bobcat S130 skid-steer loaders (municipal landscaping, small foundation digging, utility maintenance).
   • Agricultural Machinery: Kubota B26 tractor, compact harvesters (small farm tilling, greenhouse operation, turf maintenance).
   • Core Application Scenarios: Direct replacement for faulty original cylinder heads (e.g., casting cracks, valve seat wear, coolant leakage, injector bore deformation) and engine overhaul projects, restoring the D1703/D1803 engine’s compression ratio, power output, and operational stability.

Q2: What core functions does the D1703/D1803 cylinder head assy perform?

Core Functions

1. Combustion Chamber Sealing & Pressure Resistance

   Seals the top of the engine cylinder to form a closed combustion chamber, working with the cylinder block, piston, and head gasket to withstand high combustion pressure (up to 8.5MPa) and temperature (up to 1000℃). It prevents gas leakage and ensures complete fuel combustion, directly determining the machinery’s working efficiency and low-speed torque (≥85N·m for D1703, ≥92N·m for D1803 @ 1600rpm).

2. Valve Train Support & Air-Fuel Control

   Provides precise mounting positions for valves, valve springs, and rocker arms, controlling valve opening/closing timing and duration to optimize the engine’s air-fuel mixture ratio. This improves fuel efficiency by 5–6% compared to worn or non-OEM cylinder heads, reducing operating costs for small machinery fleets.

3. Cooling & Heat Dissipation Optimization

   Features integrated compact cross-flow coolant passages that circulate coolant around the combustion chamber, injector bores, and exhaust ports. The passage layout is optimized for the limited engine bay space of mini excavators and tractors, efficiently dissipating excess heat to prevent engine overheating during long-hour intermittent operation.

4. Fuel Injection System Integration

   Pre-machined high-precision injector mounting bores ensure accurate positioning of Kubota original injectors, enabling atomized fuel to be sprayed directly into the combustion chamber at high pressure (up to 100MPa). This enhances fuel atomization quality and reduces exhaust emissions, complying with global non-road engine emission standards (Tier 4 Final / Stage V).