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Yanmar 3T72SB Engine

General Technical Data

Engine Specifications

Engine Model ............... Yanmar 3T72SB
Engine Type ............... 4-cycle vertical inline 3-cylinder liquid-cooled diesel
Number of Cylinders ............... 3
Cylinder Arrangement ............... In-line
Engine Bore, in (mm) ............... 2.835 (72.0)
Engine Stroke, in (mm) ............... 2.835 (72.0)
Displacement, cu.in (L) ............... 53.64 (0.879)
Rated Engine Power, hp (kW) ............... 15.0-18.0 (11.2-13.4)
Rated Engine Speed, rpm ............... 2400-2800
Peak Torque ............... 34.7-41.3 lb-ft (47-56 Nm) at 1800-2000 rpm
Idle Speed ............... 800-900 rpm
Aspiration Type ............... Naturally Aspirated
Operating Speed ............... 2400-2800 rpm
Compression Ratio ............... 22.5:1-23.0:1
Firing Order ............... 1-3-2
Combustion Chamber ............... Swirl pre-combustion chamber type
Rotation Direction ............... Counterclockwise viewed from the flywheel face
Exhaust System Type ............... Front or side discharge dry manifold
Crankcase Ventilation ............... Closed breather circulation layout
PTO Drive Shaft Option ............... Flywheel output end and front pulley auxiliary setup
Cylinder Block Type ............... Monoblock cast iron
Cylinder Head Type ............... Single-piece cast iron
Lubrication System ............... Forced pressure circulation
Oil Pump Type ............... Trochoid gear-driven pump
Oil Filter Type ............... Full-flow cartridge spin-on
Cooling System ............... Liquid-cooled with radiator forced circulation
Water Pump Type ............... Belt-driven centrifugal pump
Air Cleaner Type ............... Dry dual-element type
Starting System ............... Electric motor starter
Electrical System ............... 12V system

Fuel System

Injection Pump Model ............... Yanmar Deck-Type In-line Pump Series
Injection Pump Type ............... In-line plunger configuration plunger style
Injection Timing ............... 16-19 deg BTDC
Injection Pressure, psi (bar) ............... 1706-1849 (118-128)
Fuel Feed Pump Type ............... Mechanical diaphragm lift configuration pump
Fuel Filter Layout ............... Spin-on element with primary water separator trap unit
Fuel Injection Nozzle ............... Throttle type throttle design needle system
Nozzle Opening Threshold, psi (bar) ............... 1706 (118)
Fuel Return Flow Setup ............... Overhead bypass spill pipe circuit back to tank source
Governor Type ............... Mechanical centrifugal multi-speed governor
Governor Spring Tension ............... Mechanical dual-spring governor linkage design
Control Rack Travel, in (mm) ............... 0.315-0.394 (8.0-10.0)
Max Fuel Lift Head, ft (m) ............... 3.28 (1.0) baseline elevation height capability
Recommended Fuel Grade ............... ASTM D975 No. 2-D ultra-low sulfur formulation diesel
Injection Nozzle Hole Count ............... Single throttle aperture orifice format
Nozzle Holder Model Type ............... YPD series or equivalent execution designator
Injection Plunger Bore, in (mm) ............... 0.197-0.236 (5.0-6.0) specification bracket
Injection Plunger Stroke, in (mm) ............... 0.236-0.276 (6.0-7.0) effective push profile
Max Allowable Vacuum Line, inHg (mmHg) ............... 3.94 (100)
Fuel Pipe Wall Clearance, in (mm) ............... 0.079 (2.0)

Dimensions and Weight

Overall Length, in (mm) ............... 19.7 (500)
Overall Width, in (mm) ............... 16.6 (423)
Overall Height, in (mm) ............... 21.6 (550)
Dry Weight, lbs (kg) ............... 287 (130)
Wet Weight, lbs (kg) ............... 309 (140)

Maintenance Data

Service Information

Standard Compression Pressure, psi (bar) ............... 398-427 (27.5-29.4)
Minimum Compression Pressure, psi (bar) ............... 341 (23.5)
Oil Pressure at Low Idle, psi (bar) ............... 14.2 (0.98)
Oil Pressure at Rated Speed, psi (bar) ............... 42.7-56.9 (2.94-3.92)
Radiator Cap Pressure Limit, psi (bar) ............... 12.8 (0.9)
Thermostat Opening Start, F (C) ............... 160 (71)
Thermostat Full Open point, F (C) ............... 185 (85)
Alternator Belt Deflection, in (mm) ............... 0.394-0.591 (10.0-15.0)
Intake Valve Clearance, Cold, in (mm) ............... 0.006-0.008 (0.15-0.20)
Exhaust Valve Clearance, Cold, in (mm) ............... 0.006-0.008 (0.15-0.20)

Engine Oil and Coolant

Engine Oil Type .................. SAE 10W-30, SAE 15W-40
API Service Classifications ......................... CD or higher
Lubricating Oil Capacity, qt (L) ............... 3.28 (3.1)
Coolant Liquid Capacity, qt (L) ............... 4.23 (4.0)

Service Intervals

Change engine oil ............... Every 100 hours
Replace oil filter ............... Every 200 hours
Replace fuel filter ............... Every 200 hours
Service air filter ............... Every 50 hours
Replace air filter ............... Every 500 hours
Change coolant ............... Every 1000 hours
Valve-lash adjustment ............... Every 500 hours
Check fuel system ............... Every 500 hours
Compression test ............... Every 1000 hours
Belt inspection ............... Every 100 hours

Service Specifications

Cylinder Bore Inside Diameter, in (mm) ............... 2.8346-2.8350 (72.000-72.010)
Cylinder Bore Maximum Out-of-Round, in (mm) ............... 0.0008 (0.02)
Cylinder Bore Maximum Taper, in (mm) ............... 0.0011 (0.03)
Connecting Rod Small End Bushing I.D, in (mm) ............... 0.8665-0.8673 (22.010-22.030)
Crankshaft Main Journal Outside Diameter, in (mm) ............... 1.9665-1.9671 (49.950-49.965)
Main Bearing Shell Inside Diameter, in (mm) ............... 1.9685-1.9696 (50.000-50.030)
Main Bearing Oil Clearance, in (mm) ............... 0.0013-0.0031 (0.035-0.080)
Crankpin Journal Outside Diameter, in (mm) ............... 1.5728-1.5734 (39.950-39.965)
Connecting Rod Big End Bearing I.D, in (mm) ............... 1.5748-1.5760 (40.000-40.030)
Connecting Rod Bearing Clearance, in (mm) ............... 0.0013-0.0031 (0.035-0.080)
Crankshaft Side Thrust Play, in (mm) ............... 0.0043-0.0090 (0.110-0.230)
Connecting Rod Big End Side Clearance, in (mm) ............... 0.0059-0.0118 (0.150-0.300)
Piston Skirt Outside Diameter, in (mm) ............... 2.8322-2.8334 (71.940-71.970)
Piston to Cylinder Wall Clearance, in (mm) ............... 0.0019-0.0027 (0.050-0.070)
Piston Pin Bore Inside Diameter, in (mm) ............... 0.8661-0.8665 (22.000-22.010)
Piston Pin Outside Diameter, in (mm) ............... 0.8657-0.8661 (21.990-22.000)
Piston Pin to Piston Pin Bore Clearance, in (mm) ............... 0.0000-0.0007 (0.000-0.020)
Piston Pin to Small End Bushing Clearance, in (mm) ............... 0.0003-0.0015 (0.010-0.040)
Top Ring Groove Width, in (mm) ............... 0.0799-0.0807 (2.030-2.050)
Second Ring Groove Width, in (mm) ............... 0.0791-0.0799 (2.010-2.030)
Oil Ring Groove Width, in (mm) ............... 0.1578-0.1586 (4.010-4.030)
Top Ring Side Clearance, in (mm) ............... 0.0027-0.0041 (0.070-0.105)
Second Ring Side Clearance, in (mm) ............... 0.0019-0.0033 (0.050-0.085)
Oil Ring Side Clearance, in (mm) ............... 0.0011-0.0027 (0.030-0.070)
Top Ring End Gap, in (mm) ............... 0.0078-0.0137 (0.200-0.350)
Second Ring End Gap, in (mm) ............... 0.0078-0.0137 (0.200-0.350)
Oil Ring End Gap, in (mm) ............... 0.0078-0.0157 (0.200-0.400)
Cylinder Head Surface Distortion Flatness, in (mm) ............... 0.0019 (0.05)
Intake Valve Guide Inside Diameter, in (mm) ............... 0.2755-0.2761 (7.000-7.015)
Exhaust Valve Guide Inside Diameter, in (mm) ............... 0.2755-0.2761 (7.000-7.015)
Intake Valve Stem Outside Diameter, in (mm) ............... 0.2736-0.2742 (6.950-6.965)
Exhaust Valve Stem Outside Diameter, in (mm) ............... 0.2724-0.2732 (6.920-6.940)
Intake Valve Stem to Guide Clearance, in (mm) ............... 0.0013-0.0025 (0.035-0.065)
Exhaust Valve Stem to Guide Clearance, in (mm) ............... 0.0023-0.0037 (0.060-0.095)
Intake Valve Head Thickness, in (mm) ............... 0.0393 (1.00)
Exhaust Valve Head Thickness, in (mm) ............... 0.0393 (1.00)
Intake Valve Seat Width, in (mm) ............... 0.0433-0.0551 (1.100-1.400)
Exhaust Valve Seat Width, in (mm) ............... 0.0511-0.0629 (1.300-1.600)
Intake Valve Sinking Depth, in (mm) ............... 0.0157-0.0275 (0.400-0.700)
Exhaust Valve Sinking Depth, in (mm) ............... 0.0157-0.0275 (0.400-0.700)
Intake Valve Seat Angle, deg ............... 45.0
Exhaust Valve Seat Angle, deg ............... 45.0
Valve Spring Standard Length, in (mm) ............... 1.4960 (38.00)
Camshaft Main Journal Outside Diameter, in (mm) ............... 1.5724-1.5732 (39.940-39.960)
Camshaft Journal Bearing Bore Inside Diameter, in (mm) ............... 1.5748-1.5767 (40.000-40.050)
Camshaft Main Journal Clearance, in (mm) ............... 0.0015-0.0043 (0.040-0.110)
Intake Cam Lobe Height, in (mm) ............... 1.2952-1.2992 (32.900-33.000)
Exhaust Cam Lobe Height, in (mm) ............... 1.2952-1.2992 (32.900-33.000)
Camshaft Thrust End Play, in (mm) ............... 0.0019-0.0059 (0.050-0.150)
Rocker Arm Shaft Outside Diameter, in (mm) ............... 0.4716-0.4722 (11.980-11.995)
Rocker Arm Bushing Inside Diameter, in (mm) ............... 0.4724-0.4731 (12.000-12.018)
Rocker Arm Shaft to Bushing Clearance, in (mm) ............... 0.0001-0.0014 (0.005-0.038)
Tappet Outside Diameter, in (mm) ............... 0.8244-0.8251 (20.940-20.960)
Tappet Guide Hole Inside Diameter, in (mm) ............... 0.8267-0.8275 (21.000-21.021)
Tappet to Guide Clearance, in (mm) ............... 0.0015-0.0031 (0.040-0.081)

Tightening Torques

Cylinder Head Bolt, lb-ft (Nm) ............... 50.6-54.2 (68.6-73.5)
Connecting Rod Cap Bolt, lb-ft (Nm) ............... 23.1-25.3 (31.4-34.3)
Main Bearing Cap Bolt, lb-ft (Nm) ............... 39.7-43.3 (53.9-58.8)
Flywheel Retaining Bolt, lb-ft (Nm) ............... 57.8-61.4 (78.4-83.3)
Crankshaft V-Pulley End Nut, lb-ft (Nm) ............... 83.1-90.4 (112.7-122.5)
Camshaft Thrust Plate Bolt, lb-ft (Nm) ............... 6.5-8.6 (8.8-11.7)
Rocker Arm Shaft Support Bolt, lb-ft (Nm) ............... 17.3-20.2 (23.5-27.4)
Valve Adjusting Locknut, lb-ft (Nm) ............... 6.5-8.6 (8.8-11.7)
Cylinder Head Cover Bonnet Bolt, lb-ft (Nm) ............... 5.0-6.5 (6.8-8.8)
Oil Pan Drain Plug, lb-ft (Nm) ............... 36.1-43.3 (49.0-58.8)
Oil Pan Mounting Bolt, lb-ft (Nm) ............... 6.5-8.6 (8.8-11.7)
Fuel Injection Nozzle Holder Nut, lb-ft (Nm) ............... 43.3-50.6 (58.8-68.6)
Fuel Injection High Pressure Pipe Nut, lb-ft (Nm) ............... 17.3-21.6 (23.5-29.4)
Fuel Pump Delivery Valve Holder, lb-ft (Nm) ............... 25.3-28.9 (34.3-39.2)
Fuel Pump Mounting Stud Nut, lb-ft (Nm) ............... 14.4-17.3 (19.6-23.5)
Exhaust Manifold Mounting Nut, lb-ft (Nm) ............... 17.3-21.6 (23.5-29.4)
Intake Manifold Mounting Bolt, lb-ft (Nm) ............... 14.4-17.3 (19.6-23.5)
Water Pump Mounting Bolt, lb-ft (Nm) ............... 14.4-17.3 (19.6-23.5)
Thermostat Housing Bolt, lb-ft (Nm) ............... 14.4-17.3 (19.6-23.5)
Starter Motor Mounting Bolt, lb-ft (Nm) ............... 28.9-36.1 (39.2-49.0)
Alternator Mounting Pivot Bolt, lb-ft (Nm) ............... 28.9-36.1 (39.2-49.0)
Alternator Adjusting Link Lockbolt, lb-ft (Nm) ............... 11.5-14.4 (15.7-19.6)
Oil Pressure Switch Sensor Body, lb-ft (Nm) ............... 10.8-14.4 (14.7-19.6)
Glow Plug Body Installation, lb-ft (Nm) ............... 10.8-14.4 (14.7-19.6)
Glow Plug Terminal Wire Nut, lb-ft (Nm) ............... 1.4-2.1 (2.0-2.9)
Gear Housing Case Cover M6 Bolt, lb-ft (Nm) ............... 6.5-8.6 (8.8-11.7)
Gear Housing Case Cover M8 Bolt, lb-ft (Nm) ............... 14.4-17.3 (19.6-23.5)
Flywheel Housing Backing Plate M8 Bolt, lb-ft (Nm) ............... 17.3-21.6 (23.5-29.4)
Flywheel Housing Backing Plate M10 Bolt, lb-ft (Nm) ............... 36.1-43.3 (49.0-58.8)
Lubricating Oil Pipe Union Eye M8 Bolt, lb-ft (Nm) ............... 8.6-11.5 (11.7-15.7)
Lubricating Oil Pipe Union Eye M10 Bolt, lb-ft (Nm) ............... 14.4-17.3 (19.6-23.5)
Lubricating Oil Pipe Union Eye M12 Bolt, lb-ft (Nm) ............... 21.6-25.3 (29.4-34.3)
Fuel Filter Bracket Mounting Bolt, lb-ft (Nm) ............... 14.4-17.3 (19.6-23.5)
Cooling Fan Pulley Nut, lb-ft (Nm) ............... 36.1-43.3 (49.0-58.8)

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