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Shibaura S723 Engine

The Shibaura S723 is a vertical, water-cooled, 4-stroke, 3-cylinder, naturally aspirated inline diesel engine. It has a total displacement of 0.879 liters (879 cc). This engine is widely utilized in compact agricultural machinery and sub-compact utility tractors. Notable applications include the Ford 1120, 1210, and 1215, the New Holland 1120 and 1215, and the Shibaura SP1440 and SP1840 models produced between 1983 and 1998. It features a robust cast-iron block design, electric starting, and integrated glow plugs for reliable cold-weather operation.

The engine employs an overhead valve configuration. The firing order is 1-2-3. Standard service specifications mandate a cold valve clearance of 0.20 mm for both the intake and exhaust valves. The engine is configured with a square layout, featuring a 72.0 mm bore and a 72.0 mm stroke. The nominal compression ratio ranges between 23.0:1 and 24.0:1.

Fuel System: This model utilizes an indirect injection (IDI) combustion system. Fuel is drawn from the tank by a mechanical fuel pump and forced through a primary fuel filter to the inline injection pump. The injection pump meters and delivers pressurized fuel to individual throttle-type fuel injectors mounted in the pre-combustion chambers of the cylinder head. A dry element air cleaner provides clean intake air induction.

Lubrication is managed via a pressure-fed internal oil pump that circulates lubricant through a full-flow spin-on oil filter. Recommended oil viscosities for typical operational ranges are SAE 10W-30 or 10W-40 diesel-grade engine oils. The engine uses a liquid-forced water-cooled cooling system driven by a belt-driven water pump. It incorporates an external radiator and cooling fan to maintain standard thermal equilibrium during heavy-duty agricultural operations.

General Technical Data

Engine Specifications

Engine Model ............... Shibaura S723
Engine Type ............... 4-cycle vertical inline 3-cylinder liquid-cooled diesel
Number of Cylinders ............... 3
Cylinder Arrangement ............... In-line
Engine Bore, in (mm) ............... 2.83 (72.0)
Engine Stroke, in (mm) ............... 2.83 (72.0)
Displacement, cu.in (L) ............... 53.6 (0.879)
Rated Engine Power, hp (kW) ............... 14.0-18.0 (10.4-13.4)
Rated Engine Speed, rpm ............... 2500-2600
Peak Torque ............... 36.0 lb-ft (48.8 Nm) at 1800 rpm
Max No Load Speed, rpm ............... 2750-2850
Minimum Idle Speed, rpm ............... 750-850
Aspiration Type ............... Naturally Aspirated
Operating Speed ............... 2500 rpm
Compression Ratio ............... 23.0:1
Firing Order ............... 1-2-3
Cylinder Block Type ............... Cast iron
Cylinder Head Type ............... Cast iron overhead valve
Lubrication System ............... Full-pressure forced lubrication
Oil Pump Type ............... Trochoid gear pump
Oil Filter Type ............... Full-flow, spin-on cartridge
Cooling System ............... Liquid-cooled with radiator
Water Pump Type ............... Belt-driven centrifugal pump
Air Cleaner Type ............... Dry element or oil bath type
Starting System ............... Electric starter motor
Electrical System ............... 12V
Alternator Capacity, V-A ............... 14A or 40A

Fuel System

Fuel Injection Pump ............... Bosch type mini inline pump
Governor Type ............... Mechanical all speed centrifugal type
Fuel Injection Nozzle ............... Throttle type nozzle
Injection Timing ............... 21.0 degrees BTDC
Injection Pressure, psi (bar) ............... 1700-1849 (117.0-127.5)
Fuel Filter Type ............... Spin-on element with water sedimentor
Fuel Feed Pump Type ............... Mechanical diaphragm type pump
Specified Fuel Grade ............... ASTM D975 No. 2D or DIN 51601
Maximum Fuel Return Flow, gph (L/h) ............... 2.64 (10.0)
Fuel Tank Capacity, gal (L) ............... 4.83 (18.3)
Maximum Fuel Temperature, F (C) ............... 140.0 (60.0)
Nozzle Opening Pressure, Std, psi (bar) ............... 1779 (122.7)
Nozzle Holder Assembly ............... Screw flange connection type
Fuel Delivery Line Diameter, in (mm) ............... 0.078 (2.0)

Dimensions and Weight

Overall Length, in (mm) ............... 19.5 (495)
Overall Width, in (mm) ............... 15.3 (390)
Overall Height, in (mm) ............... 21.8 (555)
Dry Weight, lbs (kg) ............... 179 (81)
Wet Weight, lbs (kg) ............... 194 (88)

Maintenance Data

Service Information

Compression Pressure, Standard, psi (bar) ............... 426 (29.4)
Compression Pressure, Limit, psi (bar) ............... 355 (24.5)
Oil Pressure at Rated Speed, psi (bar) ............... 42.6-56.8 (2.94-3.92)
Oil Pressure at Low Idle, psi (bar) ............... 9.95 (0.68)
Oil Temperature Range, F (C) ............... 176.0-230.0 (80.0-110.0)
Maximum Allowed Oil Temperature, F (C) ............... 248.0 (120.0)
Coolant Thermostat Opening Temperature, F (C) ............... 160.0 (71.0)
Coolant Thermostat Full Open Temperature, F (C) ............... 185.0 (85.0)
Alternator Belt Tension Deflection, in (mm) ............... 0.39-0.47 (10.0-12.0)
Intake Valve Clearance, Cold, in (mm) ............... 0.008 (0.203)
Exhaust Valve Clearance, Cold, in (mm) ............... 0.008 (0.203)

Engine Oil and Coolant

Engine Oil Type .................. SAE 30, SAE 10W-30, or 15W-40
API Service Classifications ......................... CF, CF-4, CH-4
Engine Oil Capacity with Filter, qt (L) ............... 3.17 (3.0)
Engine Oil Capacity Dry Engine, qt (L) ............... 3.70 (3.5)
Coolant Capacity Engine Only, qt (L) ............... 1.58 (1.5)

Service Intervals

Change oil and filter ............... Every 200 hours
Inspect air cleaner ............... Every 50 hours
Replace air cleaner ............... Every 400 hours
Replace fuel filter ............... Every 200 hours
Valve clearance adjustment ............... Every 400 hours
Fuel system inspection ............... Every 800 hours
Change coolant ............... Every 1000 hours
Compression test ............... Every 1000 hours
Clean radiator core ............... Every 250 hours
Inspect belt tension ............... Every 100 hours

Service Specifications

Cylinder Bore Inside Diameter, in (mm) ............... 2.834-2.835 (72.000-72.019)
Cylinder Bore Max Wear Limit, in (mm) ............... 2.842 (72.200)
Cylinder Roundness and Taper Limit, in (mm) ............... 0.0007 (0.02)
Connecting Rod Small End Bushing I.D, in (mm) ............... 0.827-0.828 (21.012-21.025)
Connecting Rod Big End I.D, in (mm) ............... 1.771-1.772 (45.000-45.015)
Crankshaft Main Journal Outside Diameter, in (mm) ............... 2.046-2.047 (51.965-51.980)
Crankpin Outside Diameter, in (mm) ............... 1.652-1.653 (41.965-41.980)
Crankshaft End Play, in (mm) ............... 0.002-0.006 (0.05-0.15)
Main Bearing Clearance, in (mm) ............... 0.0015-0.0035 (0.039-0.092)
Connecting Rod Bearing Clearance, in (mm) ............... 0.0013-0.0033 (0.035-0.085)
Piston Skirt Outside Diameter, in (mm) ............... 2.831-2.832 (71.930-71.955)
Piston to Cylinder Wall Clearance, in (mm) ............... 0.0023-0.0035 (0.060-0.089)
Piston Pin Bore Inside Diameter, in (mm) ............... 0.826-0.827 (21.000-21.009)
Piston Pin Outside Diameter, in (mm) ............... 0.826-0.827 (20.993-21.000)
Top Ring Groove Width, in (mm) ............... 0.079-0.081 (2.02-2.04)
Second Ring Groove Width, in (mm) ............... 0.079-0.080 (2.01-2.03)
Oil Ring Groove Width, in (mm) ............... 0.158-0.159 (4.01-4.03)
Top Ring End Gap, in (mm) ............... 0.006-0.012 (0.15-0.30)
Second Ring End Gap, in (mm) ............... 0.006-0.012 (0.15-0.30)
Oil Ring End Gap, in (mm) ............... 0.008-0.016 (0.20-0.40)
Intake Valve Stem Outside Diameter, in (mm) ............... 0.273-0.274 (6.955-6.970)
Exhaust Valve Stem Outside Diameter, in (mm) ............... 0.272-0.273 (6.920-6.940)
Valve Guide Inside Diameter, in (mm) ............... 0.275-0.276 (7.000-7.015)
Intake Valve Stem to Guide Clearance, in (mm) ............... 0.0011-0.0023 (0.030-0.060)
Exhaust Valve Stem to Guide Clearance, in (mm) ............... 0.0023-0.0037 (0.060-0.095)
Valve Spring Free Length, in (mm) ............... 1.378 (35.00)
Camshaft Journal Outside Diameter (Front), in (mm) ............... 1.573-1.574 (39.960-39.980)
Camshaft Journal Outside Diameter (Center), in (mm) ............... 1.533-1.534 (38.960-38.980)
Camshaft Journal Outside Diameter (Rear), in (mm) ............... 1.494-1.495 (37.960-37.980)
Cam Lobe Height (Intake), in (mm) ............... 1.321-1.323 (33.55-33.61)
Cam Lobe Height (Exhaust), in (mm) ............... 1.322-1.324 (33.58-33.64)
Rocker Arm Shaft Outside Diameter, in (mm) ............... 0.471-0.472 (11.966-11.984)
Rocker Arm Bushing Inside Diameter, in (mm) ............... 0.472-0.473 (12.000-12.018)
Rocker Arm Bushing to Shaft Clearance, in (mm) ............... 0.0006-0.0020 (0.016-0.052)
Tappet Outside Diameter, in (mm) ............... 0.785-0.786 (19.955-19.970)
Tappet Bore Block Inside Diameter, in (mm) ............... 0.787-0.788 (20.000-20.021)
Tappet to Block Clearance Standard, in (mm) ............... 0.0011-0.0025 (0.030-0.066)

Tightening Torques

Cylinder Head Bolt, lb-ft (Nm) ............... 36.1-39.7 (49.0-53.9)
Connecting Rod Cap Bolt, lb-ft (Nm) ............... 21.7-25.3 (29.4-34.3)
Main Bearing Cap Bolt, lb-ft (Nm) ............... 36.1-39.7 (49.0-53.9)
Flywheel Bolt, lb-ft (Nm) ............... 43.4-47.0 (58.8-63.7)
Crankshaft Pulley Center Nut, lb-ft (Nm) ............... 72.3-79.5 (98.0-107.8)
Camshaft Thrust Plate Bolt, lb-ft (Nm) ............... 7.2-8.7 (9.8-11.8)
Rocker Arm Shaft Bracket Bolt, lb-ft (Nm) ............... 20.2-24.6 (27.4-33.3)
Cylinder Head Cover Bolt , lb-ft (Nm) ............... 5.8-8.7 (7.8-11.8)
Oil Pan Mounting Drain Plug, lb-ft (Nm) ............... 25.3-32.5 (34.3-44.1)
Oil Pan Mounting Bolt, lb-ft (Nm) ............... 7.2-8.7 (9.8-11.8)
Fuel Injection Nozzle Assembly, lb-ft (Nm) ............... 43.4-50.6 (58.8-68.6)
Fuel Injection Pump Delivery Valve Holder, lb-ft (Nm) ............... 28.9-32.5 (39.2-44.1)
Fuel Injection Pump Mounting Nut, lb-ft (Nm) ............... 10.1-13.0 (13.7-17.6)
Fuel Injection Pipe Union Nut, lb-ft (Nm) ............... 18.1-21.7 (24.5-29.4)
Glow Plug Installation, lb-ft (Nm) ............... 10.8-14.4 (14.7-19.6)
Oil Pressure Switch Assembly, lb-ft (Nm) ............... 10.8-14.4 (14.7-19.6)
Water Temperature Sensor, lb-ft (Nm) ............... 18.1-25.3 (24.5-34.3)
Intake Manifold Mounting Bolt, lb-ft (Nm) ............... 7.2-8.7 (9.8-11.8)
Exhaust Manifold Mounting Bolt, lb-ft (Nm) ............... 7.2-8.7 (9.8-11.8)
Starter Motor Mounting Bolt, lb-ft (Nm) ............... 34.7-41.9 (47.0-56.8)
Alternator Mounting Pivot Bolt, lb-ft (Nm) ............... 14.4-18.1 (19.6-24.5)
Alternator Adjusting Link Lock Bolt, lb-ft (Nm) ............... 7.2-8.7 (9.8-11.8)
Timing Gear Case Cover Bolt, lb-ft (Nm) ............... 7.2-8.7 (9.8-11.8)
Rear Oil Seal Retainer Bolt, lb-ft (Nm) ............... 7.2-8.7 (9.8-11.8)
Fuel Feed Pump Assembly Bolt, lb-ft (Nm) ............... 7.2-8.7 (9.8-11.8)

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