Kubota D902 Engine
The Kubota D902 is a compact, high-performance diesel engine that belongs to Kubota’s Super Mini Series. This 3-cylinder, liquid-cooled engine has a displacement of 0.898 liters (54.80 cubic inches) and features a bore and stroke of 72.0 x 73.6 mm (2.83 x 2.90 inches). It is designed to meet EPA/CARB Tier 4 and EU Stage V emission regulations.
The D902 engine delivers impressive power in a small package, with a rated output of 18.5 kW (24.8 HP) at 3600 rpm and maximum torque of 56.1 Nm (41.4 lb-ft) at 2600 rpm. It utilizes an indirect injection combustion system and an in-line fuel pump. The engine’s compact dimensions (434 x 401 x 544 mm) and light dry weight of 72 kg (159 lb) make it ideal for various applications where space is at a premium.
Kubota has incorporated several features to enhance the D902’s performance and durability. The engine uses Kubota’s original E-TVCS (Three Vortex Combustion System), which has been improved for cleaner emissions. The cooling water passages between cylinder bores employ Kubota’s proprietary casting technology to manage heat load and ensure reliable performance.
The D902 is available in different variants to suit various needs. The D902-T-E4 is a turbocharged version that offers the same output of 18.5 kW but at a lower speed of 2,800 rpm, with increased maximum torque of 78 Nm at 2,000 rpm. This variant is particularly useful for high-altitude applications.
Kubota has also developed an electronically controlled version called the D902-K, which features a common rail system and a new TVCR combustion system. This variant offers improved fuel efficiency and reduced emissions, consuming approximately 5% less fuel than conventional models.
The Kubota D902 engine finds applications in a wide range of equipment, including turf industry machines, utility vehicles, mini excavators, mini-track loaders, trenchers, and welders. Its combination of compact size, high power output, and clean emissions make it a versatile choice for manufacturers across various industries.
Kubota D902 Specs
The Kubota D902 is a compact, high-performance diesel engine with the following key specifications:
Engine Type:
– 3-cylinder, vertical, water-cooled, 4-cycle diesel engine
– Indirect injection combustion system
– Displacement: 0.898 L (54.80 cu.in)
– Bore and Stroke: 72.0 x 73.6 mm (2.83 x 2.90 in)
Performance:
– Rated output: 18.5 kW (24.8 HP) at 3600 rpm
– Maximum torque: 56.1 Nm (41.4 lb-ft) at 2600 rpm
Emissions:
– Complies with EPA/CARB Tier 4 and EU Stage V emission regulations
Physical Characteristics:
– Dimensions (L x W x H): 434 x 401 x 544 mm (17.1 x 15.8 x 21.4 in)
– Dry weight: 72 kg (159 lb)
Features:
– Naturally aspirated
– In-line fuel pump
– E-TVCS (Three Vortex Combustion System) for cleaner emissions
– Centrifugal ball mechanical governor
– Forced lubrication by trochoid pump
– Pressurized radiator cooling system
The D902 engine is known for its durability, compact size, and high power output. It’s used in various applications, including turf equipment, utility vehicles, mini excavators, and welders. Kubota also offers a turbocharged version (D902-T-E4) with increased torque and better high-altitude performance, as well as alternative fuel versions (WG972-G for gasoline and WG972-GL for dual fuel: gasoline/LPG) with the same footprint.
Kubota D902 Oil Filter
The Kubota D902 engine uses a specific oil filter to maintain proper engine lubrication and performance. Here are the key details about the oil filter for the Kubota D902:
Oil Filter Specifications
– Part Number: The most common oil filter part number for the Kubota D902 is HH150-32430.
– Type: Cartridge-style oil filter
– Dimensions: The filter is compact to fit the engine’s small size, though exact measurements may vary slightly between filter brands.
Replacement Information
– Interval: The oil filter should typically be replaced every 200 hours of operation or annually, whichever comes first. However, always consult your engine’s manual for the manufacturer’s recommended maintenance schedule.
– Procedure:
1. Drain the engine oil
2. Remove the old filter
3. Clean the filter mounting surface
4. Apply a thin film of clean oil to the new filter gasket
5. Install the new filter, tightening it by hand
6. Refill with fresh engine oil
Importance
Regular oil filter replacement is crucial for:
– Removing contaminants from the engine oil
– Maintaining proper oil pressure
– Extending engine life
– Ensuring optimal engine performance
When purchasing a replacement oil filter, it’s recommended to use genuine Kubota parts or high-quality aftermarket filters that meet or exceed OEM specifications to ensure proper fitment and filtration for your D902 engine.
Kubota D902 Oil Capacity
The Kubota D902 engine has an oil capacity of 3.7 liters (3.91 US quarts or 3.26 Imperial quarts). This capacity is crucial for maintaining proper lubrication and optimal performance of the engine.
When it comes to oil type, Kubota recommends using engine oil with CD or CE service classifications. The recommended SAE viscosity for the D902 is 10W-30 or 10W-40. These multi-grade oils provide good protection across a range of temperatures, which is important for the various applications in which the D902 is used.
Regular oil changes are essential for the longevity and performance of the D902 engine. Typically, the oil should be changed every 200 hours of operation or annually, whichever comes first. However, this interval may vary depending on the specific application and operating conditions. It’s always best to consult the engine’s manual or a Kubota dealer for the most accurate maintenance schedule.
When changing the oil, it’s important to also replace the oil filter. The most common oil filter part number for the D902 is HH150-32430. This ensures that the new oil remains clean and free from contaminants.
The oil level should be checked regularly, ideally before each use of the equipment. The D902 is equipped with an oil dipstick for easy level checking. When checking the oil level, ensure the engine is on level ground and has been off for a few minutes to allow the oil to settle in the pan.
Proper oil maintenance is critical for the D902’s performance and longevity. Insufficient oil levels or using oil that’s past its service life can lead to increased wear, reduced efficiency, and potentially severe engine damage. On the other hand, overfilling can cause foaming and reduced lubrication effectiveness.
Given the compact size of the D902 engine, its 3.7-liter oil capacity is sufficient to provide adequate lubrication for all its moving parts while maintaining its efficient and compact design. This oil capacity contributes to the engine’s reputation for reliability and durability across various applications, from turf equipment to mini excavators and utility vehicles.
Kubota D902 Parts
The Kubota D902 diesel engine has a wide range of parts available to support its operation and maintenance.
Engine Components:
– Cylinder head
– Pistons and connecting rods
– Crankshaft
– Camshaft
– Valves and valve springs
– Timing gears and chain
Fuel System:
– Fuel injectors
– Fuel injection pump
– Fuel lines and fittings
– Fuel filters
Lubrication System:
– Oil pump
– Oil filter
– Oil pan
– Oil cooler
Cooling System:
– Water pump
– Thermostat
– Radiator
– Cooling fan and belt
Electrical System:
– Starter motor
– Alternator
– Glow plugs
– Wiring harness
Air Intake and Exhaust:
– Air filter
– Intake manifold
– Exhaust manifold
– Muffler
Gaskets and Seals:
– Head gasket
– Oil seals
– Valve cover gasket
– Intake and exhaust gaskets
Engine Accessories:
– Flywheel
– Pulley
– Engine mounts
Overhaul Kits:
– Complete overhaul kits containing gaskets, seals, and other wear parts are available for comprehensive engine rebuilds.
When replacing parts on a Kubota D902 engine, it’s crucial to use components that meet or exceed OEM specifications to ensure proper fit and function. Many of these parts are specific to the engine’s serial number, so it’s important to have this information when ordering replacements.
Regular maintenance and timely replacement of wear items such as filters, belts, and hoses can significantly extend the life of the D902 engine and maintain its performance in various applications, from construction equipment to agricultural machinery.
Kubota D902 Parts Diagram
The Kubota D902 engine is a compact, three-cylinder diesel engine with various components that work together to provide efficient performance. Components :
Engine Block:
The engine block forms the core of the D902, housing the crankshaft, connecting rods, and pistons. It also contains the water jackets for cooling.
Cylinder Head:
Mounted on top of the engine block, the cylinder head contains the valves, valve springs, and combustion chambers. It’s secured to the block with head bolts.
Crankshaft:
Located at the bottom of the engine block, the crankshaft converts the reciprocating motion of the pistons into rotational motion.
Pistons and Connecting Rods:
Three pistons move up and down within the cylinders, connected to the crankshaft via connecting rods.
Camshaft:
Positioned above the crankshaft, the camshaft controls the opening and closing of the valves.
Fuel System:
Includes the fuel injection pump, fuel injectors, and fuel lines. The in-line pump delivers fuel to the injectors.
Intake and Exhaust System:
Comprises the air filter, intake manifold, exhaust manifold, and muffler.
Cooling System:
Consists of the water pump, thermostat, radiator, and cooling fan.
Lubrication System:
Includes the oil pump, oil filter, and oil passages throughout the engine.
Electrical Components:
Features the starter motor, alternator, and glow plugs for cold starting.
Timing Gear:
Located at the front of the engine, it synchronizes the camshaft with the crankshaft.
The D902’s compact design integrates these components efficiently, resulting in a powerful yet space-saving engine suitable for various applications.
Kubota D902 Fuel Filter
The Kubota D902 engine uses a specific fuel filter to ensure clean fuel delivery and optimal engine performance. Here are the key details about the fuel filter for the Kubota D902:
The most common fuel filter element part number for the Kubota D902 is 15231-43560. This filter element is designed to fit into a fuel filter assembly, which is typically mounted on the engine.
The fuel filter for the D902 is a spin-on type with a M20 x 1.5 thread. It has an outside sealing ring diameter of 62mm and an overall outside diameter of 72mm. The height of the filter is approximately 72mm.
Kubota recommends replacing the fuel filter every 400 hours of operation or annually, whichever comes first. However, this interval may need to be shortened in dusty or dirty environments.
The fuel filter plays a crucial role in protecting the engine’s fuel system components, including the fuel injection pump and injectors, from contaminants and water. It helps maintain the engine’s performance and longevity by ensuring only clean fuel reaches the combustion chamber.
When replacing the fuel filter, it’s important to follow proper procedures:
1. Close the fuel valve
2. Remove the old filter
3. Clean the mounting surface
4. Apply a thin film of clean fuel to the new filter gasket
5. Install the new filter, tightening it by hand
6. Open the fuel valve and bleed the fuel system
For optimal engine protection and performance, it’s recommended to use genuine Kubota fuel filters or high-quality aftermarket filters that meet or exceed OEM specifications. Regular fuel filter replacement is an essential part of maintaining the D902 engine’s efficiency and reliability across its various applications.
Kubota D902 Rebuild Kit
A Kubota D902 rebuild kit typically includes the essential components needed to overhaul the engine. These kits are designed to restore the engine’s performance and extend its service life. A standard rebuild kit for the Kubota D902 usually contains the following parts:
1. Piston set (3 pistons)
2. Piston ring set
3. Cylinder liner set
4. Main bearings
5. Rod bearings
6. Thrust washers
7. Complete gasket set (including head gasket, oil pan gasket, and various seals)
8. Valve stem seals
9. Connecting rod bushings
Some more comprehensive rebuild kits may also include:
10. Camshaft bushings
11. Oil pump
12. Water pump
13. Thermostat
It’s important to note that rebuild kits can vary in their contents depending on the manufacturer and the level of rebuild required. Some kits may offer additional components such as:
– Valves
– Valve guides
– Rocker arms
– Push rods
– Timing gears
When purchasing a rebuild kit for a Kubota D902 engine, it’s crucial to ensure that all parts are compatible with your specific engine serial number, as there can be variations even within the same model.
Before beginning the rebuild process, it’s recommended to thoroughly inspect other engine components not included in the kit, such as the crankshaft, camshaft, and cylinder head, to determine if they need replacement or machining.
A proper engine rebuild using a quality kit can significantly extend the life of your Kubota D902 engine and restore its original performance characteristics. However, the rebuild process requires specialized tools and expertise, so it’s often best performed by experienced mechanics or engine rebuilders.
Installation of Rebuild Kit
To properly install a Kubota D902 rebuild kit, follow these general steps:
1. Thoroughly clean the engine block, cylinder head, and all components that will be reused.
2. Install new cylinder liners if included in the kit, ensuring proper seating and sealing.
3. Install new pistons and connecting rods, using the provided piston rings. Ensure correct orientation and gap positioning of the rings.
4. Install new main bearings and rod bearings, applying engine oil to all bearing surfaces.
5. Carefully reinstall the crankshaft, ensuring proper end play and alignment.
6. Install new thrust washers if provided.
7. Replace the camshaft bushings if included in the kit.
8. Install new valve stem seals and reassemble the valve train components.
9. Apply the new head gasket and torque the cylinder head bolts to the specified torque in the correct sequence.
10. Install new oil seals for the crankshaft and camshaft.
11. Replace the oil pump if a new one is provided in the kit.
12. Install the new water pump and thermostat.
13. Replace all gaskets and seals included in the kit, such as the oil pan gasket and valve cover gasket.
14. Reassemble remaining engine components, ensuring all fasteners are torqued to specifications.
15. Fill the engine with fresh oil and coolant.
16. Perform any necessary adjustments, such as valve clearances.
Throughout the rebuild process, refer to the engine’s service manual for specific torque specifications, clearances, and assembly procedures. Proper cleaning, careful assembly, and adherence to specifications are crucial for a successful rebuild of the Kubota D902 engine.
Kubota D902 Starter
The Kubota D902 engine uses several different starter motor options, depending on the specific application and requirements. Here are some key details about starters for the Kubota D902:
Common starter specifications include:
– 12V voltage
– Power ratings ranging from 0.8 kW to 1.4 kW
– 8 or 9 teeth on the starter gear
Some typical starter configurations for the D902 include:
– 12V, 0.95 kW starter
– 12V, 1.4 kW starter
– 12V, 1.2 kW starter
– 24V, 1.4 kW starter (for some applications)
The starters are generally geared reduction type with clockwise rotation. They often have a flange diameter of around 66mm.
When replacing the starter, it’s important to match the voltage, power rating, and physical mounting specifications to ensure proper fitment and function. The exact part number needed can vary based on the engine’s serial number and application.
Starter replacement is typically straightforward:
1. Disconnect the battery
2. Remove the old starter
3. Install the new starter
4. Reconnect electrical connections
5. Reconnect the battery
Regular starter maintenance, including checking electrical connections and keeping the starter clean, can help extend its lifespan. If experiencing starting issues, it’s advisable to have the entire starting system checked, including the battery and alternator, not just the starter motor itself.
For optimal performance and reliability, using OEM Kubota parts or high-quality aftermarket starters designed specifically for the D902 engine is recommended.
Kubota D902 Head Gasket
The head gasket for the Kubota D902 engine is a critical component that seals the cylinder head to the engine block. Here are some key details about the D902 head gasket:
The head gasket for the Kubota D902 is typically made of multi-layered steel (MLS) for durability and effective sealing. It’s designed to withstand high temperatures and pressures within the engine.
The gasket’s dimensions are specific to the D902 engine, with three cylinder openings to match the engine’s three-cylinder configuration. The thickness of the gasket is crucial for maintaining the correct compression ratio and can vary slightly depending on the specific application.
When replacing the head gasket on a D902 engine, it’s important to ensure the mating surfaces of both the cylinder head and engine block are clean and free from any debris or old gasket material. The head bolts should be replaced and torqued to the manufacturer’s specifications in the correct sequence.
The head gasket replacement is often part of a more comprehensive engine overhaul, and it’s common to replace other components such as head bolts, valve stem seals, and other related gaskets at the same time.
Proper installation of the head gasket is crucial for preventing coolant and oil leaks, maintaining compression, and ensuring optimal engine performance. If not installed correctly, it can lead to engine overheating, loss of compression, or oil contamination.
When purchasing a replacement head gasket for a Kubota D902, it’s advisable to use OEM parts or high-quality aftermarket gaskets that meet or exceed OEM specifications to ensure proper fit and function.
Replacement of Head Gasket
Head gaskets are typically only replaced when there are signs of failure or during a major engine overhaul.
Some key points regarding the D902 head gasket:
– It should be replaced if there are signs of head gasket failure, such as coolant mixing with oil, loss of compression, or overheating issues.
– Replacing the head gasket is often part of a more comprehensive engine overhaul process.
– When replacing the head gasket, it’s important to use OEM parts or high-quality aftermarket gaskets that meet OEM specifications.
– Proper installation, including cleaning mating surfaces and torquing head bolts to spec, is crucial for proper sealing.
– Other related components like head bolts are often replaced at the same time as the head gasket.
Rather than having a set replacement interval, it’s more important to monitor engine performance and address any signs of head gasket issues promptly if they occur. Regular maintenance of the cooling system and proper engine operation can help extend head gasket life.
Kubota D902 Head Bolt Torque Specs
The head bolt torque specifications for the Kubota D902 engine are as follows:
For M8x1.25 head bolts:
39.2-44.1 Nm (4.0-4.5 kgf-m, 28.9-32.5 lb-ft)
When tightening the head bolts, it’s important to follow the proper sequence and use a torque wrench to ensure even pressure distribution. The bolts should be tightened in multiple stages, typically in a spiral pattern from the center outward.
It’s recommended to replace the head bolts when reinstalling the cylinder head, as they are designed to stretch slightly during initial installation for optimal clamping force.
Proper torquing of the head bolts is crucial for maintaining the seal between the cylinder head and engine block, preventing coolant and oil leaks, and ensuring correct engine compression. Always refer to the engine’s service manual for the most up-to-date specifications and detailed tightening procedures.
Kubota D902 Fuel Pump
The Kubota D902 engine uses an in-line fuel injection pump. Here are some key details about the fuel pump for this engine:
The fuel pump is a mechanical type, specifically a Bosch MD mini fuel injection pump. This pump is responsible for delivering fuel to the injectors at the correct pressure and timing.
The injection timing for the D902 is typically set at 20 degrees before top dead center (BTDC), though this can vary slightly between engine versions.
The fuel injection pressure for the D902 is approximately 13.7 MPa (1990 psi). This high pressure is necessary for proper fuel atomization and combustion.
The pump is driven by the engine’s timing gears, ensuring synchronization with the engine’s rotation. It features a centrifugal ball mechanical governor to regulate engine speed.
When replacing or servicing the fuel pump, it’s crucial to maintain proper timing and calibration. Improper setup can lead to poor engine performance, increased emissions, or potential engine damage.
Regular maintenance of the fuel system, including replacing fuel filters at recommended intervals, is important for the longevity and proper function of the fuel pump.
If issues arise with the fuel pump, such as loss of power or difficulty starting, it’s often best to have it diagnosed and repaired by a qualified technician familiar with Kubota engines, as the fuel system requires specialized knowledge and tools for proper service.
Kubota D902 Oil Type
For the Kubota D902 engine, the recommended oil type is:
Engine oil with CD or CE service classifications
The recommended SAE viscosity grades are:
SAE 10W-30 or SAE 10W-40
These multi-grade oils provide good protection across a range of temperatures, which is important for the various applications in which the D902 is used.
The oil capacity for the D902 engine is 3.7 liters (3.91 US quarts or 3.26 Imperial quarts).
It’s important to use high-quality engine oil that meets these specifications to ensure proper lubrication and protection of engine components. Regular oil changes at the intervals specified in the engine manual are crucial for maintaining engine performance and longevity.
When operating in extreme temperatures or conditions, consult the engine manual or a Kubota dealer for specific oil recommendations that may be better suited to those environments.
Kubota D902 Cylinder Head
The Kubota D902 cylinder head is a critical component of this compact diesel engine. Here are some key details about the D902 cylinder head:
The cylinder head is made of cast iron and designed to fit the three-cylinder configuration of the D902 engine. It contains the combustion chambers, valves, and ports for the intake and exhaust systems.
The D902 uses Kubota’s E-TVCS (Three Vortex Combustion System) combustion chamber design in the cylinder head. This helps improve fuel efficiency and reduce emissions.
The cylinder head houses the valvetrain components, including intake and exhaust valves, valve springs, and rocker arms. Proper valve clearance adjustment is important for optimal engine performance.
When servicing the cylinder head, it’s crucial to use the correct torque specifications when reinstalling. The head bolts should be tightened in the proper sequence to ensure even clamping force.
Cylinder head gaskets for the D902 are typically made of multi-layered steel for durability. Replacing the head gasket requires careful cleaning of the mating surfaces on both the head and engine block.
If the cylinder head needs to be replaced, Kubota offers complete cylinder head kits that come assembled with valves installed, simplifying the repair process.
Regular maintenance, including checking for leaks and proper coolant levels, can help prevent issues with the cylinder head. If overheating occurs, it’s important to inspect the cylinder head for potential damage or warping.
When rebuilding the engine, it’s recommended to have the cylinder head inspected and potentially resurfaced to ensure a proper seal with the engine block.
Kubota D902-ef03
The Kubota D902-E4B is a compact, high-performance diesel engine that belongs to Kubota’s Super Mini Series. Here are the key specifications and features:
Engine Type:
3-cylinder, vertical, water-cooled 4-cycle diesel engine
Displacement: 0.898 L (54.80 cu.in)
Bore and Stroke: 72.0 x 73.6 mm (2.83 x 2.90 in)
Performance:
Rated output: 18.5 kW (24.8 HP) at 3600 rpm
Maximum torque: 56.1 Nm (41.4 lb-ft) at 2600 rpm
Emissions:
Complies with EPA/CARB Tier 4 and EU Stage V emission regulations
Physical Characteristics:
Dimensions (L x W x H): 434 x 401 x 544 mm (17.1 x 15.8 x 21.4 in)
Dry weight: 72 kg (159 lb)
Features:
Indirect injection combustion system
In-line fuel pump
Naturally aspirated
No aftertreatment required
The D902-E4B offers high power output in a compact package, making it suitable for various applications including utility vehicles, mini excavators, trenchers, and welders. It features Kubota’s E-TVCS (Three Vortex Combustion System) for cleaner emissions and improved fuel efficiency. The engine maintains the same footprint as its predecessors, allowing for easy integration into existing machine designs.
Kubota D902 Injection Pump
The Kubota D902 engine uses an in-line fuel injection pump. Here are some key details about the injection pump for this engine:
The fuel injection pump is a Bosch MD mini type. This mechanical pump is responsible for delivering fuel to the injectors at the correct pressure and timing.
The injection timing for the D902 is typically set at 20 degrees before top dead center (BTDC). The fuel injection pressure is approximately 13.7 MPa (1990 psi).
The pump features a centrifugal ball mechanical governor to regulate engine speed. It’s driven by the engine’s timing gears, ensuring synchronization with the engine’s rotation.
When servicing or replacing the injection pump, it’s crucial to maintain proper timing and calibration. Improper setup can lead to poor engine performance, increased emissions, or potential engine damage.
Regular maintenance of the fuel system, including replacing fuel filters at recommended intervals, is important for the longevity and proper function of the injection pump.
If issues arise with the injection pump, such as loss of power or difficulty starting, it’s often best to have it diagnosed and repaired by a qualified technician familiar with Kubota engines. The fuel system requires specialized knowledge and tools for proper service.
When replacing the injection pump, it’s typically sold on a service exchange basis, meaning the old pump must be returned. Always use OEM parts or high-quality aftermarket components that meet or exceed OEM specifications to ensure proper fit and function.
Kubota D902 Replacement Engine
The Kubota D902 can be replaced with several options:
1. New OEM Kubota D902 engine: This is an exact replacement that meets all original specifications. It comes with a manufacturer’s warranty and ensures perfect compatibility.
2. Remanufactured Kubota D902: These engines are rebuilt to OEM specifications using a combination of new and reconditioned parts. They offer a more cost-effective option while still providing reliable performance.
3. Kubota D902-T-E4: This is a turbocharged version of the D902 that offers the same output of 18.5 kW but at a lower speed of 2,800 rpm. It has increased maximum torque of 78 Nm at 2,000 rpm, making it suitable for high-altitude applications.
4. Aftermarket replacement engines: Some companies produce compatible engines designed to replace the D902. These may offer cost savings but require careful verification of specifications and fitment.
5. Upgraded Kubota models: In some cases, newer Kubota engine models with similar dimensions and improved performance characteristics can be used as replacements, though this may require some modifications.
When selecting a replacement engine, consider factors such as:
– Power output and torque requirements
– Physical dimensions and mounting points
– Emissions compliance for your application
– Availability of parts and service support
– Cost of the engine and any necessary modifications
It’s important to consult with a Kubota dealer or engine specialist to ensure the replacement engine meets all requirements for your specific application. They can provide guidance on the best option based on your needs, budget, and any regulatory considerations.