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Shibaura N844 Engine

The Shibaura N844 is a heavy-duty, 4-cylinder, 4-stroke, liquid-cooled, inline industrial diesel engine developed by ISM Shibaura. Highly regarded for its compact footprints, longevity, and high torque density, it is heavily utilized globally across agricultural, construction, and power generation equipment. It famously powers various machinery, including New Holland skid steers and sub-compact tractors. The engine block is designed for exceptional rigidity, delivering low vibration and balanced thermal distribution during extreme operations.

This power unit uses an overhead valve (OHV) configuration actuated via a pushrod system driven by the internal camshaft. It features 2 valves per cylinder (1 intake, 1 exhaust) for a total of 8 valves. Cold service valve clearance maintenance must be performed strictly to workshop specifications. The engine architecture has a standard core cylinder bore diameter of 84.0 mm. The vertical piston stroke length is 90.0 mm for the base 1.995-liter (122 cubic inches) displacement block.

Fuel System: Fuel distribution utilizes a mechanical, inline multi-plunger Bosch-type injection pump assembly. Pressurized fuel routes from the primary fuel filter to individual high-pressure line injectors following a strict 1-3-4-2 firing order sequence. Engine shutdown safety monitoring is directly controlled via an integrated electronic fuel shutoff solenoid, requiring precise external mechanical installation extending to a standard workshop protrusion measurement between 25.5-26.4 mm.

Engine lubrication is established via a full-pressure fed system driven by a high-efficiency trochoid oil pump driven off the crankshaft gear train. Pressurized oil channels directly through an integrated full-flow spin-on cartridge oil filter to the main bearings, connecting rod journals, and overhead rocker assemblies. The thermal management incorporates a closed-circuit, forced circulation, liquid-cooling framework. A belt-driven centrifugal water pump continuously propels coolant through the engine block water jackets and cylinder head passages to isolate excess combustion heat. The system includes an integrated wax-pellet type bypass thermostat to govern cold-start heating cycles, linked to an external heavy-duty radiator and mechanical fan assembly.

General Technical Data

Engine Specifications

Engine Model ............... Shibaura N844
Engine Type ............... 4-cycle inline 4-cylinder liquid-cooled diesel
Number of Cylinders ............... 4
Cylinder Arrangement ............... In-line vertical
Engine Bore, in (mm) ............... 3.31 (84.0)
Engine Stroke, in (mm) ............... 3.54 (90.0)
Displacement, cu.in (L) ............... 121.7 (1.995)
Rated Engine Power, hp (kW) ............... 30.0-40.0 (22.4-29.8)
Rated Engine Speed, rpm ............... 2500-2600
Peak Torque ............... 92.2 lb-ft (125.0 Nm) at 1800 rpm
Idle Speed, rpm ............... 800-900
Max No-Load Speed, rpm ............... 2750-2850
Aspiration Type ............... Naturally aspirated
Combustion System ............... Indirect injection (IDI)
Compression Ratio ............... 22.5:1
Firing Order ............... 1-3-4-2
Rotation Direction ............... Counterclockwise viewed from flywheel
Cylinder Block Type ............... Monoblock cast iron
Cylinder Head Type ............... One-piece cast iron
Lubrication System ............... Forced pressure feed by gear pump
Oil Pump Type ............... Trochoid gear-driven
Oil Filter Type ............... Full-flow spin-on cartridge
Cooling System ............... Forced liquid circulation with radiator
Water Pump Type ............... Centrifugal belt-driven
Cooling Fan Type ............... Suction or pusher type dynamic plastic
Air Cleaner Type ............... Dry element dual cartridge
Starting System ............... Electric starter motor
Starter Voltage, V ............... 12
Alternator Rating, A ............... 40-55

Fuel System

Fuel Injection Pump Type ............... Bosch inline cassette-type mechanical pump
Fuel Injection Pump Drive ............... Gear drive via camshaft train
Fuel Injector Type ............... Throttle nozzle type multi-hole
Injection Timing, deg ............... 19.0-21.0 BTDC
Injection Pressure, psi (MPa) ............... 2132.0-2275.0 (14.7-15.7)
Fuel Transfer Pump Type ............... Mechanical plunger / diaphragm type
Fuel Filter Type ............... Spin-on element with water separator ring
Fuel Feed Minimum Pressure, psi (kPa) ............... 2.9 (20.0)
Fuel Return Line Maximum Pressure, psi (kPa) ............... 7.3 (50.0)
Fuel Tank Vent Venting Pressure, psi (kPa) ............... 0.15 (1.0)
Fuel Injection Line Outer Diameter, in (mm) ............... 0.236 (6.0)
Fuel Injection Line Inner Diameter, in (mm) ............... 0.078 (2.0)
Fuel Return Tube Diameter, in (mm) ............... 0.196 (5.0)
Governor Type ............... Mechanical centrifugal all-speed
Governor High Idle Limit, rpm ............... 2800
Governor Low Idle Limit, rpm ............... 850

Dimensions and Weight

Overall Length, in (mm) ............... 22.3 (565)
Overall Width, in (mm) ............... 19.8 (505)
Overall Height, in (mm) ............... 26.5 (675)
Dry Weight, lbs (kg) ............... 419 (190)
Wet Weight, lbs (kg) ............... 450 (204)

Maintenance Data

Service Information

Compression Pressure, Minimum, psi (MPa) ............... 426.0 (2.94) at 200 rpm
Compression Pressure, Limit Value, psi (MPa) ............... 355.0 (2.45) at 200 rpm
Maximum Variance Between Cylinders, psi (MPa) ............... 36.2 (0.25)
Oil Pressure at Idle, psi (kPa) ............... 9.9 (68.9)
Oil Pressure at Rated Speed, psi (kPa) ............... 35.5-56.8 (245.0-392.0)
Oil Relief Valve Opening Pressure, psi (MPa) ............... 49.7-63.9 (0.34-0.44)
Thermostat Opening Temperature, F (C) ............... 160.0 (71.0) or 180.0 (82.0)
Thermostat Full Open Temperature, F (C) ............... 185.0 (85.0) or 203.0 (95.0)
Cooling System Cap Pressure, psi (kPa) ............... 7.1-12.8 (49.0-88.0)
Fan Belt Deflection Distance, in (mm) ............... 0.39-0.59 (10.0-15.0)
Intake Valve Clearance, in (mm) ............... 0.008 (0.20)
Exhaust Valve Clearance, in (mm) ............... 0.008 (0.20)

Engine Oil and Coolant

Engine Oil Type .................. SAE 5W-30, SAE 10W-30, or 15W-40
API Service Classifications ......................... CH-4, CG-4, CF-4, or CI-4
Engine Oil Capacity with Filter, qt (L) ............... 6.3-8.5 (6.0-8.0)
Engine Oil Capacity, Sump Only, qt (L) ............... 5.8-7.9 (5.5-7.5)
Coolant Capacity, Engine Only, qt (L) ............... 3.0 (2.8)
Coolant Capacity, Total System, qt (L) ............... 7.4-9.5 (7.0-9.0)

Service Intervals

Change oil and filter ............... Every 250 hours
Inspect air cleaner ............... Every 50 hours
Replace air cleaner ............... Every 1000 hours
Replace fuel filter ............... Every 500 hours
Valve clearance adjustment ............... Every 1000 hours
Fuel system inspection ............... Every 1000 hours
Change coolant ............... Every 2000 hours
Compression test ............... Every 2000 hours
Clean radiator core ............... Every 250 hours
Inspect belt tension ............... Every 100 hours

Service Specifications

Cylinder Bore Standard Diameter, in (mm) ............... 3.3071-3.3079 (84.000-84.019)
Cylinder Bore Wear Limit Diameter, in (mm) ............... 3.3150 (84.200)
Cylinder Bore Roundness, in (mm) ............... 0.0008 (0.020)
Cylinder Bore Taper Limit, in (mm) ............... 0.0008 (0.020)
Cylinder Liner Inside Diameter, in (mm) ............... 3.3071-3.3079 (84.000-84.019)
Cylinder Liner Outside Diameter, in (mm) ............... 3.4252-3.4260 (87.000-87.022)
Cylinder Block Liner Bore Diameter, in (mm) ............... 3.4240-3.4248 (86.968-86.990)
Main Journal Diameter, in (mm) ............... 2.6755-2.6760 (67.955-67.967)
Main Journal Taper Limit, in (mm) ............... 0.0004 (0.010)
Main Bearing Shell Thickness, in (mm) ............... 0.0783-0.0787 (1.990-2.000)
Main Bearing Oil Clearance, in (mm) ............... 0.0017-0.0040 (0.044-0.102)
Crankshaft End Play, in (mm) ............... 0.0020-0.0118 (0.050-0.300)
Thrust Washer Thickness, in (mm) ............... 0.0768-0.0787 (1.950-2.000)
Crankpin Journal Diameter, in (mm) ............... 2.0458-2.0463 (51.964-51.975)
Connecting Rod Small End Bushing ID, in (mm) ............... 1.1031-1.1039 (28.020-28.038)
Connecting Rod Small End Bore w/o Bushing, in (mm) ............... 1.2205-1.2213 (31.000-31.020)
Connecting Rod Big End Bore Diameter, in (mm) ............... 2.1654-2.1661 (55.000-55.019)
Connecting Rod Bearing Oil Clearance, in (mm) ............... 0.0014-0.0033 (0.035-0.085)
Connecting Rod Big End Side Play, in (mm) ............... 0.0039-0.0118 (0.100-0.300)
Piston Skirt Diameter, in (mm) ............... 3.3041-3.3051 (83.925-83.950)
Piston to Cylinder Clearance, in (mm) ............... 0.0020-0.0037 (0.050-0.094)
Piston Pin Bore Diameter, in (mm) ............... 1.1024-1.1027 (28.002-28.010)
Piston Pin Outer Diameter, in (mm) ............... 1.1020-1.1023 (27.994-28.000)
Piston Pin to Bore Clearance, in (mm) ............... 0.0001-0.0006 (0.002-0.016)
Top Ring Groove Width, in (mm) ............... 0.0799-0.0807 (2.030-2.050)
Second Ring Groove Width, in (mm) ............... 0.0602-0.0610 (1.530-1.550)
Oil Ring Groove Width, in (mm) ............... 0.1587-0.1594 (4.030-4.050)
Top Ring Side Clearance, in (mm) ............... 0.0024-0.0039 (0.060-0.100)
Second Ring Side Clearance, in (mm) ............... 0.0020-0.0035 (0.050-0.090)
Oil Ring Side Clearance, in (mm) ............... 0.0012-0.0028 (0.030-0.070)
Top Ring End Gap, in (mm) ............... 0.0079-0.0138 (0.200-0.350)
Second Ring End Gap, in (mm) ............... 0.0079-0.0138 (0.200-0.350)
Oil Ring End Gap, in (mm) ............... 0.0079-0.0157 (0.200-0.400)
Cylinder Head Bottom Face Warpage, in (mm) ............... Less than 0.002 (0.050)
Intake Valve Clearance, Cold, in (mm) ............... 0.0079-0.0080 (0.200-0.203)
Exhaust Valve Clearance, Cold, in (mm) ............... 0.0079-0.0080 (0.200-0.203)
Intake Valve Stem Outer Diameter, in (mm) ............... 0.2738-0.2744 (6.955-6.970)
Exhaust Valve Stem Outer Diameter, in (mm) ............... 0.2726-0.2732 (6.926-6.940)
Valve Guide Inside Diameter, in (mm) ............... 0.2756-0.2762 (7.000-7.015)
Intake Valve Stem to Guide Clearance, in (mm) ............... 0.0012-0.0024 (0.030-0.060)
Exhaust Valve Stem to Guide Clearance, in (mm) ............... 0.0024-0.0035 (0.060-0.089)
Valve Face Angle, deg ............... 45
Valve Seat Angle, deg ............... 45
Valve Spring Free Length, in (mm) ............... 1.3780 (35.000)
Camshaft Journal Diameter (Front), in (mm) ............... 1.8484-1.8492 (46.945-46.966)
Camshaft Journal Diameter (Center), in (mm) ............... 1.8091-1.8098 (45.955-45.975)
Camshaft Journal Diameter (Rear), in (mm) ............... 1.7701-1.7709 (44.960-44.980)
Camshaft Bearing Housing I.D (Front), in (mm) ............... 1.8504-1.8514 (47.000-47.025)
Camshaft Bearing Housing I.D (Center), in (mm) ............... 1.8110-1.8120 (46.000-46.025)
Camshaft Bearing Housing I.D (Rear), in (mm) ............... 1.7717-1.7726 (45.000-45.025)
Camshaft Journal Oil Clearance, in (mm) ............... 0.0013-0.0033 (0.034-0.085)
Intake Cam Lobe Height, in (mm) ............... 1.3417-1.3441 (34.080-34.140)
Exhaust Cam Lobe Height, in (mm) ............... 1.3417-1.3441 (34.080-34.140)
Camshaft End Play, in (mm) ............... 0.0028-0.0087 (0.070-0.220)
Tappet Lifter Outer Diameter, in (mm) ............... 0.4706-0.4711 (11.955-11.970)
Tappet Guide Bore Block Diameter, in (mm) ............... 0.4724-0.4731 (12.000-12.018)
Tappet to Guide Clearance, in (mm) ............... 0.0012-0.0025 (0.030-0.063)
Rocker Arm Shaft Outer Diameter, in (mm) ............... 0.4594-0.4600 (11.669-11.684)
Rocker Arm Bushing Inside Diameter, in (mm) ............... 0.4606-0.4622 (11.700-11.740)
Rocker Arm to Shaft Clearance, in (mm) ............... 0.0006-0.0028 (0.016-0.071)
Crank Gear to Idler Gear Backlash, in (mm) ............... 0.0031-0.0043 (0.080-0.110)
Cam Gear to Idler Gear Backlash, in (mm) ............... 0.0031-0.0043 (0.080-0.110)
Pump Gear to Idler Gear Backlash, in (mm) ............... 0.0031-0.0043 (0.080-0.110)
Ider Gear Shaft Outer Diameter, in (mm) ............... 1.3364-1.3374 (33.944-33.970)
Idler Gear Bushing Inside Diameter, in (mm) ............... 1.3386-1.3400 (34.000-34.034)
Idler Gear to Shaft Clearance, in (mm) ............... 0.0012-0.0035 (0.030-0.090)

Tightening Torques

Cylinder Head Fastener Bolts (M10), lb-ft (Nm) ............... 72.3-75.9 (98.0-103.0)
Connecting Rod Cap Nuts (M9), lb-ft (Nm) ............... 36.2-39.8 (49.0-54.0)
Main Bearing Carrier Bolts (M10), lb-ft (Nm) ............... 36.2-39.8 (49.0-54.0)
Main Bearing Carrier to Block Bolts (M8), lb-ft (Nm) ............... 21.7-25.3 (29.4-34.3)
Crankshaft Front Pulley Center Nut (M24), lb-ft (Nm) ............... 216.9-224.2 (294.0-304.0)
Flywheel Retaining Bolts (M10), lb-ft (Nm) ............... 50.6-57.9 (68.6-78.5)
Rocker Arm Shaft Assembly Brackets (M8), lb-ft (Nm) ............... 20.0-23.8 (27.1-32.3)
Valve Timing Gear Case Cover Bolts (M6), lb-ft (Nm) ............... 7.2-8.7 (9.8-11.8)
Valve Timing Gear Case Back Plate Bolts (M8), lb-ft (Nm) ............... 17.4-21.7 (23.5-29.4)
Oil Pan Drain Plug Fitting Thread, lb-ft (Nm) ............... 25.3-32.5 (34.3-44.1)
Oil Pan Perimeter Retaining Bolts (M6), lb-ft (Nm) ............... 7.2-8.7 (9.8-11.8)
Oil Suction Screen Tube Bolt (M8), lb-ft (Nm) ............... 17.4-21.7 (23.5-29.4)
Cylinder Head Valve Cover Nuts (M6), lb-ft (Nm) ............... 5.8-7.2 (7.9-9.8)
Intake Manifold Securing Bolts (M8), lb-ft (Nm) ............... 17.4-21.7 (23.5-29.4)
Exhaust Manifold Securing Bolts (M8), lb-ft (Nm) ............... 17.4-21.7 (23.5-29.4)
Fuel Injector Assembly Retaining Nuts (M20), lb-ft (Nm) ............... 43.4-50.6 (58.8-68.6)
Fuel Injection Pipe Union Delivery Nuts (M12), lb-ft (Nm) ............... 18.1-21.7 (24.5-29.4)
Fuel Leak-off Line Banjo Fitting Bolts (M10), lb-ft (Nm) ............... 14.5-18.1 (19.6-24.5)
Fuel Injection Pump Cassette Mounting Bolts (M8), lb-ft (Nm) ............... 17.4-21.7 (23.5-29.4)
Fuel Injection Pump Delivery Valve Holders, lb-ft (Nm) ............... 28.9-32.5 (39.2-44.1)
Glow Plug Terminal Small Hex Nuts (M4), lb-ft (Nm) ............... 0.7-1.1 (1.0-1.5)
Glow Plug Assembly Body Thread (M10), lb-ft (Nm) ............... 10.8-14.5 (14.7-19.6)
Starter Motor Flange Mounting Bolts (M10), lb-ft (Nm) ............... 36.2-43.4 (49.0-58.8)
Alternator Pivoting Mounting Bolt (M10), lb-ft (Nm) ............... 36.2-43.4 (49.0-58.8)
Alternator Tension Link Adjusting Bolt (M8), lb-ft (Nm) ............... 14.5-18.1 (19.6-24.5)
Oil Pressure Switch Sensor Body Thread, lb-ft (Nm) ............... 10.8-14.5 (14.7-19.6)
Water Temperature Sender Sensor Thread, lb-ft (Nm) ............... 18.1-21.7 (24.5-29.4)
Cooling Fan Blade Retaining Bolts (M6), lb-ft (Nm) ............... 7.2-8.7 (9.8-11.8)
Thermostat Housing Water Outlet Bolts (M8), lb-ft (Nm) ............... 17.4-21.7 (23.5-29.4)
Water Pump Assembly Retaining Bolts (M8), lb-ft (Nm) ............... 17.4-21.7 (23.5-29.4)

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• Shibaura Engines Specs
  
• Shibaura N843 Specs
  
• Shibaura N843L Specs
  
• Shibaura N843T-F Specs
  
• Shibaura N844L Specs
  
• Shibaura N844LT Specs
  
• Shibaura N844T Specs
  

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