________________________________________________________________________________

Shibaura N843 Engine

The Shibaura N843 is a compact, naturally aspirated, multi-purpose industrial diesel engine engineered by Shibaura. Known for its structural durability and high reliability, this engine features a heavy-duty reinforced cast iron block mated to precision-machined internal components. It is heavily utilized worldwide as a premium replacement power unit for agricultural tractors (such as the New Holland TC31/TC34 and Boomer series), commercial mowers, skid steers, and diverse industrial machinery applications. The engine is designed around an indirect injection configuration to deliver low noise, consistent cold weather ignition, and steady torque output across varying load cycles.

The powerhead utilizes an in-line overhead valve (OHV) system operated via a conventional camshaft, pushrod, and rocker arm assembly. The intake and exhaust valves operate on a fixed mechanical tolerance profile. The reciprocating assembly features a robust three-cylinder configuration engineered with a square/nearly-square ratio optimized for mechanical efficiency. Configuration: 3 cylinders, in-line vertical. Cylinder Bore: 84 mm. Piston Stroke: 90 mm. Displacement: 1.496 Liters (1496 cc).

Fuel System: The fuel system uses a highly stable indirect combustion setup designed to handle varied sulfur levels while keeping exhaust output optimized. Combustion Type: Swirl chamber (Indirect Injection / IDI) system. Injection Pump: Mechanical Bosch PFR style inline injection pump delivering synchronized high-pressure delivery to individual injectors. Governor: Mechanical, all-speed governor integrated into the timing gear case to adjust fueling automatically based on load. Shutoff System: Fitted with an electronic 12V fuel shutoff solenoid designed with a 1.00-1.04 inch protrusion profile to instantaneously cut fuel flow at the injection pump rack when deactivated.

Engine lubrication is executed via a full-pressure system to ensure long-term durability under heavy continuous loading. Lubrication Mechanism: Forced lubrication system driven by a high-efficiency mechanical hydraulic oil pump. Protection Circuit: Equipped with an integrated low-oil shutdown pressure switch calibrated to complete a ground circuit under 4.25 psi to protect the bearings from starvation. Thermal regulation is managed by a closed-loop liquid circuit to handle severe ambient heat and sustained high-RPM operation. Cooling Mechanism: Liquid, forced water-cooled design utilizing an engine-driven water pump and an external radiator configuration.

General Technical Data

Engine Specifications

Engine Model ............... Shibaura N843
Engine Type ............... 4-cycle inline 3-cylinder liquid-cooled diesel
Number of Cylinders ............... 3
Cylinder Arrangement ............... In-line
Engine Bore, in (mm) ............... 3.31 (84.0)
Engine Stroke, in (mm) ............... 3.54 (90.0)
Displacement, cu.in (L) ............... 91.3 (1.496)
Rated Engine Power, hp (kW) ............... 28.4-32.2 (21.2-24.0)
Rated Engine Speed, rpm ............... 2500-2800
Peak Torque, lb-ft (Nm) ............... 67.1-70.8 (91.0-96.0) at 1800 rpm
Low Idle Speed, rpm ............... 900-1000
High Idle Speed, rpm ............... 2700-2950
Aspiration Type ............... Naturally aspirated
Compression Ratio ............... 22.0:1-23.0:1
Firing Order ............... 1-2-3
Cylinder Block Material ............... Cast iron
Cylinder Head Material ............... Cast iron
Combustion System ............... Indirect injection, swirl chamber
Direction of Rotation ............... Counter-clockwise facing flywheel side
Lubrication System ............... Full pressure feed
Oil Pump Type ............... Trochoid rotor type, gear driven
Oil Filter Type ............... Full flow cartridge spin-on type
Cooling System ............... Forced liquid circulation with thermostat
Water Pump Type ............... Centrifugal belt-driven type
Thermostat Type ............... Wax pellet type
Air Cleaner Type ............... Dry element element dual-stage
Starting System ............... Electric starter motor with glow plugs
Electrical System, V ............... 12
Alternator Output, A ............... 40-55

Fuel System

Fuel Injection Pump Type ............... Bosch PFR in-line mini pump
Fuel Injection Pump Drive ............... Camshaft driven via roller tappet
Fuel Injector Type ............... Throttle type nozzle
Fuel Injector Nozzle Holder ............... Flange mount type
Injection Timing, deg BTDC ............... 18-20
Initial Injection Pressure, psi (MPa) ............... 1708-1849 (11.8-12.8)
Fuel Transfer Pump Type ............... Mechanical diaphragm type
Governor Type ............... Mechanical all-speed centrifugal
Fuel Filter Type ............... Spin-on cartridge with water separator element
Fuel Feed Line Diameter, in (mm) ............... 0.236 (6.0)
Fuel Return Line Diameter, in (mm) ............... 0.187 (4.75)
Maximum Fuel Pump Suction Lift, ft (m) ............... 3.3 (1.0)
Maximum Fuel System Restriction, in Hg (kPa) ............... 4.0 (13.5)
Fuel Tank Vent Requirement, cfm (L/min) ............... 0.5 (14.2)
Fuel Specification ............... ASTM D975 No. 2-D ultra low sulfur diesel
Fuel Injection Pipe Outer Diameter, in (mm) ............... 0.25 (6.35)
Fuel Injection Pipe Inner Diameter, in (mm) ............... 0.078 (2.0)
Nozzle Injection Spray Angle, deg ............... 4
Fuel Supply Pressure Minimum, psi (kPa) ............... 2.9 (20.0)
Fuel Supply Pressure Maximum, psi (kPa) ............... 5.8 (40.0)

Dimensions and Weight

Overall Length, in (mm) ............... 21.8 (555)
Overall Width, in (mm) ............... 18.9 (480)
Overall Height, in (mm) ............... 25.4 (645)
Dry Weight, lbs (kg) ............... 331 (150)

Maintenance Data

Service Information

Cylinder Compression Pressure, Standard, psi (MPa) ............... 426 (2.94)
Cylinder Compression Pressure, Limit, psi (MPa) ............... 355 (2.45)
Max Compression Variation Between Cylinders, psi (MPa) ............... 28.4 (0.2)
Oil Pressure at Rated Speed, psi (kPa) ............... 42.6-56.8 (294-392)
Oil Pressure at Idle Speed, psi (kPa) ............... 9.9 (68.6)
Oil Pressure Relief Valve Opening Pressure, psi (kPa) ............... 56.8-71.1 (392-490)
Thermostat Valve Opening Temperature, F (C) ............... 169-176 (76.5-80.0)
Thermostat Full Open Temperature, F (C) ............... 194 (90.0)
V-Belt Deflection at 22 lb (98 N) Force, in (mm) ............... 0.39-0.47 (10.0-12.0)
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 30, SAE 10W-30, or 15W-40
API Service Classifications ......................... CF, CF-4, CH-4, or CI-4
Engine Oil Capacity with Filter, qt (L) ............... 6.1 (5.8)
Engine Oil Capacity without Filter, qt (L) ............... 5.5 (5.2)
Cooling System Capacity, qt (L) ............... 2.9 (2.7)

Service Intervals

Change oil and filter ............... Every 200 hours
Inspect air cleaner ............... Every 100 hours
Replace air cleaner ............... Every 1000 hours
Replace fuel filter ............... Every 250 hours
Valve clearance adjustment ............... Every 1000 hours
Fuel system inspection ............... Every 500 hours
Change coolant ............... Every 2000 hours
Compression test ............... Every 2000 hours
Clean radiator core ............... Every 300 hours
Inspect belt tension ............... Every 200 hours

Service Specifications

Cylinder Block Bore Standard Diameter, in (mm) ............... 3.3071-3.3079 (84.000-84.019)
Cylinder Block Bore Service Limit, in (mm) ............... 3.3150 (84.200)
Cylinder Block Bore Taper, in (mm) ............... 0.0004 (0.010)
Cylinder Block Upper Surface Flatness, in (mm) ............... 0.0020 (0.050)
Con Rod Small End Bushing Inner Diameter, in (mm) ............... 1.1028-1.1033 (28.012-28.025)
Connecting Rod Big End Side Play, in (mm) ............... 0.0039-0.0118 (0.100-0.300)
Connecting Rod Bearing Oil Clearance, in (mm) ............... 0.0014-0.0033 (0.035-0.085)
Crankpin Journal Standard Diameter, in (mm) ............... 2.0458-2.0463 (51.964-51.975)
Crankpin Journal Out-of-Roundness, in (mm) ............... 0.0002 (0.005)
Crankshaft Main Journal Standard Diameter, in (mm) ............... 2.6755-2.6760 (67.957-67.970)
Crankshaft Main Journal Out-of-Roundness, in (mm) ............... 0.0002 (0.005)
Crankshaft Main Bearing Oil Clearance, in (mm) ............... 0.0016-0.0035 (0.040-0.090)
Crankshaft Free End Play, in (mm) ............... 0.0020-0.0069 (0.050-0.175)
Crankshaft Timing Gear Journal Diameter, in (mm) ............... 1.3783-1.3791 (35.012-35.030)
Piston Skirt Outer Diameter, in (mm) ............... 3.3045-3.3053 (83.935-83.954)
Piston to Cylinder Bore Clearance, in (mm) ............... 0.0022-0.0033 (0.055-0.084)
Piston Pin Bore Standard Diameter, in (mm) ............... 1.1024-1.1027 (28.002-28.010)
Piston Pin Bore Service Limit, in (mm) ............... 1.1039 (28.040)
Piston Pin Outer Diameter, in (mm) ............... 1.1021-1.1024 (27.992-28.000)
Piston Pin to Piston Pin Bore Clearance, in (mm) ............... 0.0001-0.0007 (0.002-0.018)
Piston Pin to Small End Bushing Clearance, in (mm) ............... 0.0004-0.0010 (0.010-0.025)
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) ............... 0.0008-0.0024 (0.020-0.060)
Top Ring End Gap, in (mm) ............... 0.0079-0.0138 (0.200-0.350)
Second Ring End Gap, in (mm) ............... 0.0059-0.0118 (0.150-0.300)
Oil Ring End Gap, in (mm) ............... 0.0079-0.0157 (0.200-0.400)
Cylinder Head Lower Surface Flatness, in (mm) ............... 0.0020 (0.050)
Valve Guide Standard Inner Diameter, in (mm) ............... 0.2756-0.2762 (7.000-7.015)
Intake Valve Stem Outer Diameter, in (mm) ............... 0.2736-0.2742 (6.950-6.965)
Exhaust Valve Stem Outer Diameter, in (mm) ............... 0.2724-0.2732 (6.920-6.940)
Intake Valve Stem to Guide Clearance, in (mm) ............... 0.0014-0.0026 (0.035-0.065)
Exhaust Valve Stem to Guide Clearance, in (mm) ............... 0.0024-0.0037 (0.060-0.095)
Intake Valve Seat Angle, deg ............... 45
Exhaust Valve Seat Angle, deg ............... 45
Intake Valve Face Angle, deg ............... 45
Exhaust Valve Face Angle, deg ............... 45
Valve Spring Free Length, in (mm) ............... 1.3780 (35.000)
Camshaft Journal Diameter (Front), in (mm) ............... 1.7697-1.7705 (44.950-44.970)
Camshaft Journal Diameter (Middle), in (mm) ............... 1.7618-1.7626 (44.750-44.770)
Camshaft Journal Diameter (Rear), in (mm) ............... 1.7539-1.7547 (44.550-44.570)
Camshaft Journal Oil Clearance, in (mm) ............... 0.0012-0.0035 (0.030-0.090)
Cam Lobe Height (Intake), in (mm) ............... 1.3406-1.3421 (34.050-34.090)
Cam Lobe Height (Exhaust), in (mm) ............... 1.3406-1.3421 (34.050-34.090)
Camshaft End Play, in (mm) ............... 0.0020-0.0059 (0.050-0.150)
Camshaft Timing Gear Journal Diameter, in (mm) ............... 1.1028-1.1037 (28.012-28.033)
Rocker Arm Shaft Outer Diameter, in (mm) ............... 0.4705-0.4713 (11.950-11.970)
Rocker Arm Bushing Inner Diameter, in (mm) ............... 0.4724-0.4739 (12.000-12.035)
Rocker Arm to Shaft Clearance, in (mm) ............... 0.0012-0.0033 (0.030-0.085)
Tappet Standard Outer Diameter, in (mm) ............... 0.4701-0.4709 (11.940-11.960)
Tappet Guide Bore Standard Diameter, in (mm) ............... 0.4724-0.4735 (12.000-12.025)
Tappet to Guide Bore Clearance, in (mm) ............... 0.0016-0.0033 (0.040-0.085)
Idle Gear Journal Standard Diameter, in (mm) ............... 1.5728-1.5738 (39.950-39.975)
Idle Gear Bushing Inner Diameter, in (mm) ............... 1.5748-1.5758 (40.000-40.025)
Idle Gear to Journal Clearance, in (mm) ............... 0.0010-0.0030 (0.025-0.075)

Tightening Torques

Cylinder Head Bolts (M10), lb-ft (Nm) ............... 65.0-69.0 (88.0-93.5)
Connecting Rod Cap Bolts (M8), lb-ft (Nm) ............... 36.0-40.0 (49.0-54.0)
Main Bearing Cap Bolts (M10), lb-ft (Nm) ............... 36.0-40.0 (49.0-54.0)
Flywheel Retaining Bolts (M10), lb-ft (Nm) ............... 51.0-55.0 (69.0-74.5)
Crankshaft Pulley Center Bolt (M14), lb-ft (Nm) ............... 87.0-94.0 (118.0-127.0)
Rocker Arm Shaft Bracket Bolts (M8), lb-ft (Nm) ............... 20.0-24.0 (27.0-32.5)
Valve Cover Nut (M6), lb-ft (Nm) ............... 6.0-9.0 (8.0-12.0)
Flywheel Housing Mounting Bolts (M8), lb-ft (Nm) ............... 20.0-24.0 (27.0-32.5)
Flywheel Housing Mounting Bolts (M10), lb-ft (Nm) ............... 36.0-43.0 (49.0-58.0)
Timing Gear Case Cover Bolts (M8), lb-ft (Nm) ............... 15.0-19.0 (20.0-26.0)
Oil Pan Mounting Bolts (M8), lb-ft (Nm) ............... 15.0-19.0 (20.0-26.0)
Oil Pan Drain Plug (M14), lb-ft (Nm) ............... 22.0-29.0 (30.0-39.0)
Fuel Injection Pump Delivery Valve Holder, lb-ft (Nm) ............... 29.0-33.0 (39.0-45.0)
Fuel Injection Pump Mounting Nuts (M8), lb-ft (Nm) ............... 15.0-19.0 (20.0-26.0)
Fuel Injector Assembly into Head (M20), lb-ft (Nm) ............... 43.0-51.0 (58.0-69.0)
Fuel Injection Pipe Cap Nuts (M12), lb-ft (Nm) ............... 18.0-22.0 (24.0-29.5)
Fuel Leak-Off Pipe Assembly Nut, lb-ft (Nm) ............... 15.0-18.0 (20.0-24.5)
Glow Plug Hex Nut (M10), lb-ft (Nm) ............... 11.0-15.0 (15.0-20.0)
Glow Plug Connector Cord Nut (M4), lb-ft (Nm) ............... 0.7-1.1 (1.0-1.5)
Oil Pressure Switch (M10), lb-ft (Nm) ............... 11.0-15.0 (15.0-20.0)
Coolant Temperature Sensor (M16), lb-ft (Nm) ............... 22.0-29.0 (30.0-39.0)
Water Pump Mounting Bolts (M8), lb-ft (Nm) ............... 15.0-19.0 (20.0-26.0)
Thermostat Housing Cover Bolts (M8), lb-ft (Nm) ............... 15.0-19.0 (20.0-26.0)
Intake Manifold Mounting Bolts (M8), lb-ft (Nm) ............... 15.0-19.0 (20.0-26.0)
Exhaust Manifold Mounting Bolts (M8), lb-ft (Nm) ............... 18.0-22.0 (24.0-29.5)
Starter Motor Mounting Bolts (M10), lb-ft (Nm) ............... 36.0-43.0 (49.0-58.0)
Alternator Mounting Pivot Bolt (M10), lb-ft (Nm) ............... 36.0-43.0 (49.0-58.0)
Alternator Adjusting Link Bolt (M8), lb-ft (Nm) ............... 15.0-19.0 (20.0-26.0)
Oil Pump Cover Plate Screws (M6), lb-ft (Nm) ............... 5.0-7.0 (7.0-9.5)
Oil Relief Valve Plug assembly, lb-ft (Nm) ............... 29.0-36.0 (39.0-49.0)
Idler Gear Shaft Retaining Bolt (M8), lb-ft (Nm) ............... 18.0-22.0 (24.0-29.5)
Camshaft Thrust Plate Fasteners (M8), lb-ft (Nm) ............... 15.0-19.0 (20.0-26.0)
Exhaust Pipe Flange Mounting Nuts (M8), lb-ft (Nm) ............... 18.0-22.0 (24.0-29.5)
Air Cleaner Bracket Support Bolts (M8), lb-ft (Nm) ............... 15.0-19.0 (20.0-26.0)
Fan Drive Pulley Retaining Bolts (M6), lb-ft (Nm) ............... 6.0-9.0 (8.0-12.0)
Engine Mounting Bracket to Block Bolts (M10), lb-ft (Nm) ............... 36.0-43.0 (49.0-58.0)

________________________________________________________________________________________

• Shibaura Engines Specs
  
• Shibaura N843L Specs
  
• Shibaura N843T-F Specs
  
• Shibaura N844 Specs
  
• Shibaura N844L Specs
  
• Shibaura N844LT Specs
  
• Shibaura N844T Specs
  

________________________________________________________________________________

________________________________________________________________________________________

_______________________________________________________________________________________

________________________________________________________________________________________

________________________________________________________________________________________

________________________________________________________________________________________

________________________________________________________________________________________

________________________________________________________________________________________

________________________________________________________________________________________

________________________________________________________________________________________