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Yanmar 3D82AE Engine

The Yanmar 3D82AE (interchangeably classified under Komatsu utility applications as the 3TNV82A base) is a heavy-duty, vertical, in-line, 4-cycle, water-cooled industrial diesel engine. Known for its compact footprint and high structural reliability, this naturally aspirated engine utilizes a direct injection configuration to deliver optimized combustion efficiency. It is extensively utilized in mini-excavators, agricultural tractors, utility generators, and commercial turf equipment. The engine architecture focuses on low emissions and minimal noise signature, complying with strict international industrial emission tiers through high-precision mechanical fuel delivery control.

Valve Configuration: Overhead Valve (OHV) Layout. Actuated via a gear-driven camshaft via pushrods and rocker assemblies. Number of Valve: 2 valves per cylinder (1 intake, 1 exhaust), totaling 6 valves. Cylinder Bore: 82.0 mm (3.22 in). Piston Stroke: 84.0 mm (3.30 in). Total Displacement: 1.33 Liters (1330 cc). Lubrication System: Forced lubrication regulated by a trochoid-type oil pump. Filtration: Full-flow, spin-on cartridge oil filter combined with an internal pressure regulating bypass valve. Cooling System: Liquid-cooled, forced-circulation system driven by a centrifugal, belt-driven water pump. Flow Regulation: Controlled via a wax-pellet type bypass thermostat.

Fuel System Description: Direct injection chamber utilizing a high-efficiency multi-hole nozzle configuration. Injection Pump: Features a high-pressure inline mechanical distribution pump (or specialized Yanmar MP pump depending on production year) optimized to minimize cylinder-to-cylinder fuel delivery variations. System Components: Incorporates a mechanical fuel feed pump, a spin-on primary fuel filter, and a dedicated water separator/sedimenter to protect the high-pressure system from moisture damage.

General Technical Data

Engine Specifications

Engine Model ............... Yanmar 3D82AE
Engine Type ............... 4-cycle vertical inline 3-cylinder liquid-cooled diesel
Number of Cylinders ............... 3
Cylinder Arrangement ............... In-line
Engine Bore, in (mm) ............... 3.23 (82.0)
Engine Stroke, in (mm) ............... 3.31 (84.0)
Displacement, cu.in (L) ............... 81.2 (1.331)
Rated Engine Power, hp (kW) ............... 25.0-29.4 (18.6-21.9)
Rated Engine Speed, rpm ............... 2600-3000
Peak Torque, lb-ft (Nm) ............... 52.4-58.3 (71.1-79.0) at 1800-2000 rpm
Low Idle Speed, rpm ............... 950-1050
High Idle Speed, rpm ............... 2800-3200
Aspiration Type ............... Naturally Aspirated
Compression Ratio ............... 18.0:1-19.0:1
Firing Order ............... 1-3-2
Direction of Rotation ............... Counterclockwise viewed from flywheel side
Cylinder Block Type ............... Cast iron monoblock
Cylinder Head Type ............... Cast iron single piece head
Combustion Chamber ............... Direct injection swirl chamber configuration
Lubrication System ............... Full-pressure forced lubrication circuit
Oil Pump Type ............... Trochoid gear-driven mechanical pump
Oil Filter Type ............... Full-flow, spin-on cartridge type
Cooling System ............... Liquid-cooled with forced radiator circulation
Water Pump Type ............... Belt-driven centrifugal impeller mechanical pump
Air Cleaner Type ............... Dry dual-element heavy duty paper filter element
Emission Certification ............... EPA Tier 2 and Stage II regulatory compliance
Starting System ............... Electric motor starter mechanism
Electrical System, V ............... 12
Alternator Capacity, A ............... 40-55

Fuel System

Fuel Injection Pump Type ............... Bosch PFE inline individual plunger mechanical type
Fuel Feed Pump Type ............... Electromagnetic or mechanical diaphragm type pump
Fuel Injection Nozzle Type ............... Multi-hole nozzle injector system
Fuel Injection Pressure, psi (MPa) ............... 2843.0-2987.0 (19.6-20.6)
Fuel Injection Timing, deg BTDC ............... 14.0-16.0
Fuel Filter Type ............... Spin-on cartridge type with built-in water separator bowl
Fuel Type Recommendation ............... Ultra-low sulfur diesel fuel standard ASTM D975 No. 2-D
Fuel Return Line Layout ............... Overhead spill pipe configuration routing back to tank
Fuel Injection Pipe Outer Diameter, in (mm) ............... 0.24 (6.0)
Fuel Injection Pipe Inner Diameter, in (mm) ............... 0.08 (2.0)
Plunger Diameter, in (mm) ............... 0.24 (6.0)
Plunger Stroke, in (mm) ............... 0.28 (7.0)
Delivery Valve Opening Pressure, psi (MPa) ............... 426.0 (2.9)
Nozzle Hole Diameter, in (mm) ............... 0.01 (0.2)
Maximum Fuel System Backpressure, in Hg (kPa) ............... 1.5 (5.1)
Priming Pump Type ............... Manual mechanical lever priming plunger device
Governor Type ............... Mechanical all-speed centrifugal governor flyweight system
Governor Linkage Style ............... Internal mechanical sliding rack linkage assembly
Stop Solenoid Operation Style ............... Energize-to-run or energize-to-stop mechanical linkage
Fuel Tank Vent System ............... Atmospheric open breather mechanism

Dimensions and Weight

Overall Length, in (mm) ............... 21.6 (550)
Overall Width, in (mm) ............... 19.3 (490)
Overall Height, in (mm) ............... 22.8 (580)
Dry Weight, lbs (kg) ............... 243 (110)
Wet Weight, lbs (kg) ............... 265 (120)

Maintenance Data

Service Information

Cylinder Compression Pressure (Std), psi (MPa) ............... 426.0-469.0 (2.94-3.24)
Cylinder Compression Pressure (Limit), psi (MPa) ............... 341.0 (2.35)
Max Pressure Difference Between Cylinders, psi (MPa) ............... 28.4-42.6 (0.20-0.30)
Oil Pressure at Rated Speed, psi (MPa) ............... 42.6-56.9 (0.29-0.39)
Oil Pressure at Idle Speed, psi (MPa) ............... 8.5 (0.06)
Standard Oil Operating Temperature, F (C) ............... 185.0-221.0 (85.0-105.0)
Standard Coolant Operating Temperature, F (C) ............... 167.0-194.0 (75.0-90.0)
Thermostat Opening Temperature, F (C) ............... 160.0 (71.0)
Thermostat Full Open Temperature, F (C) ............... 185.0 (85.0)
V-Belt Tension Deflection (under 22 lb Force), in (mm) ............... 0.39-0.59 (10.0-15.0)

Engine Oil and Coolant

Engine Oil Type .................. SAE 30, SAE 10W-30, or SAE 10W
API Service Classifications ......................... CD, CF, CF-4, CI-4
Engine Oil Capacity (High Level), qt (L) ............... 5.8 (5.5)
Engine Oil Capacity (Low Level), qt (L) ............... 3.7 (3.5)
Coolant Capacity, Block Only, qt (L) ............... 2.1 (2.0)
Coolant Capacity with Radiator, qt (L) ............... 5.3 (5.0)

Service Intervals

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

Service Specifications

Cylinder Bore Inside Diameter, in (mm) ............... 3.2283-3.2287 (82.000-82.010)
Cylinder Bore Inside Diameter (Max), in (mm) ............... 3.2362 (82.200)
Cylinder Maximum Bore Out-of-Round, in (mm) ............... 0.0004 (0.010)
Cylinder Block Upper Surface Flatness Distortion, in (mm) ............... 0.0020 (0.050)
Connecting Rod Small End Bushing I.D, in (mm) ............... 0.9059-0.9067 (23.010-23.030)
Con Rod Small End Bushing to Piston Pin Clearance, in (mm) ............... 0.0004-0.0014 (0.010-0.035)
Crankshaft Main Journal Outer Diameter, in (mm) ............... 1.8492-1.8496 (46.974-46.984)
Crankshaft Main Bearing Shell Bushing I.D, in (mm) ............... 1.8504-1.8513 (47.000-47.022)
Crankshaft Main Bearing Oil Clearance, in (mm) ............... 0.0006-0.0019 (0.016-0.048)
Crankpin Outer Diameter, in (mm) ............... 1.6525-1.6529 (41.974-41.984)
Crankpin Journal Bearing Inside Diameter, in (mm) ............... 1.6535-1.6543 (42.000-42.018)
Crankpin Journal Oil Clearance, in (mm) ............... 0.0043 (0.110)
Crankshaft Axial End Play, in (mm) ............... 0.0043-0.0083 (0.110-0.210)
Crankshaft Thrust Washer Thickness, in (mm) ............... 0.0768-0.0787 (1.950-2.000)
Connecting Rod Big End Axial Play, in (mm) ............... 0.0079-0.0157 (0.200-0.400)
Piston Skirt Outer Diameter, in (mm) ............... 0.870 (22.00)
Piston Outer Diameter, in (mm) ............... 3.2260-3.2264 (81.940-81.950)
Piston-to-Cylinder Bore Clearance, in (mm) ............... 0.0020-0.0028 (0.050-0.070)
Piston Pin Bore Inside Diameter, in (mm) ............... 0.9055-0.9059 (23.000-23.009)
Piston Pin Outer Diameter, in (mm) ............... 0.9053-0.9055 (22.995-23.000)
Piston Pin to Piston Pin Bore Clearance, in (mm) ............... 0.0000-0.0006 (0.000-0.014)
Top Ring Groove Width, in (mm) ............... 0.0610-0.0618 (1.550-1.570)
Second Ring Groove Width, in (mm) ............... 0.0591-0.0598 (1.500-1.520)
Oil Ring Groove Width, in (mm) ............... 0.1181-0.1189 (3.000-3.020)
Top Ring Thickness, in (mm) ............... 0.0579-0.0587 (1.470-1.490)
Second Ring Thickness, in (mm) ............... 0.0563-0.0571 (1.430-1.450)
Oil Ring Thickness, in (mm) ............... 0.1157-0.1165 (2.940-2.960)
Top Ring Groove Side Clearance, in (mm) ............... 0.0024-0.0039 (0.060-0.100)
Second Ring Groove Side Clearance, in (mm) ............... 0.0020-0.0035 (0.050-0.090)
Oil Ring Groove Side Clearance, in (mm) ............... 0.0016-0.0031 (0.040-0.080)
Top Ring End Gap, in (mm) ............... 0.0059-0.0118 (0.150-0.300)
Second Ring End Gap, in (mm) ............... 0.0071-0.0130 (0.180-0.330)
Oil Ring End Gap, in (mm) ............... 0.0079-0.0157 (0.200-0.400)
Cylinder Head Lower Surface Flatness Distortion, in (mm) ............... 0.0020 (0.050)
Intake Valve Seat Angle ............... 120.0 deg
Exhaust Valve Seat Angle ............... 90.0 deg
Intake Valve Stem Outer Diameter, in (mm) ............... 0.2736-0.2742 (6.950-6.965)
Exhaust Valve Stem Outer Diameter, in (mm) ............... 0.2732-0.2738 (6.940-6.955)
Intake Valve Guide Inside Diameter, in (mm) ............... 0.2756-0.2762 (7.000-7.015)
Exhaust Valve Guide Inside Diameter, in (mm) ............... 0.2756-0.2762 (7.000-7.015)
Intake Valve Stem to Guide Clearance, in (mm) ............... 0.0014-0.0026 (0.035-0.065)
Exhaust Valve Stem to Guide Clearance, in (mm) ............... 0.0018-0.0030 (0.045-0.075)
Intake Valve Sinkage Depth, in (mm) ............... 0.0157-0.0236 (0.400-0.600)
Exhaust Valve Sinkage Depth Assembly, in (mm) ............... 0.0157-0.0236 (0.400-0.600)
Valve Spring Free Length, in (mm) ............... 1.4882 (37.800)
Camshaft Journal Outer Diameter (Gear), in (mm) ............... 1.5724-1.5732 (39.940-39.960)
Camshaft Journal Bushing I.D (Gear), in (mm) ............... 1.5748-1.5778 (40.000-40.075)
Camshaft Journal Bearing Clearance (Gear), in (mm) ............... 0.0016-0.0053 (0.040-0.135)
Camshaft Journal Outer Diameter (Middle), in (mm) ............... 1.5709-1.5717 (39.910-39.930)
Camshaft Journal Hole Block I.D (Middle), in (mm) ............... 1.5748-1.5758 (40.000-40.025)
Camshaft Journal Bearing Clearance (Middle), in (mm) ............... 0.0028-0.0045 (0.070-0.115)
Camshaft Journal Outer Diameter (Flywheel), in (mm) ............... 1.5724-1.5732 (39.940-39.960)
Camshaft Journal Hole Inside Diameter (Flywheel), in (mm) ............... 1.5748-1.5758 (40.000-40.025)
Camshaft Journal Bearing Clearance (Flywheel), in (mm) ............... 0.0016-0.0033 (0.040-0.085)
Intake Cam Lobe Height, in (mm) ............... 1.3406-1.3445 (34.050-34.150)
Exhaust Cam Lobe Height, in (mm) ............... 1.3406-1.3445 (34.050-34.150)
Camshaft Axial End Play, in (mm) ............... 0.0020-0.0059 (0.050-0.150)
Rocker Arm Shaft Outer Diameter, in (mm) ............... 0.4713-0.4719 (11.972-11.984)
Rocker Arm Bushing Inside Diameter, in (mm) ............... 0.4724-0.4734 (12.000-12.025)
Rocker Arm Shaft to Bushing Clearance, in (mm) ............... 0.0006-0.0021 (0.016-0.053)
Tappet Lifter Outer Diameter, in (mm) ............... 0.4711-0.4717 (11.966-11.984)
Tappet Lifter Bore Block Inside Diameter, in (mm) ............... 0.4724-0.4732 (12.000-12.018)
Tappet Lifter to Bore Clearance, in (mm) ............... 0.0006-0.0020 (0.016-0.052)

Tightening Torques

Cylinder Head Bolts, lb-ft (Nm) ............... 39.1-43.4 (53.0-59.0)
Connecting Rod Cap Bolts, lb-ft (Nm) ............... 16.6-20.3 (22.5-27.5)
Main Bearing Cap Bolts, lb-ft (Nm) ............... 39.1-43.4 (53.0-59.0)
Flywheel Retaining Bolts, lb-ft (Nm) ............... 59.3-65.1 (80.4-88.3)
Crankshaft Pulley Center Bolt, lb-ft (Nm) ............... 61.4-68.7 (83.3-93.2)
Camshaft Thrust Plate Bolts, lb-ft (Nm) ............... 7.2-8.7 (9.8-11.8)
Camshaft Timing Gear Bolt, lb-ft (Nm) ............... 57.9-65.1 (78.5-88.3)
Rocker Arm Shaft Bracket Holding Bolts, lb-ft (Nm) ............... 16.6-20.3 (22.5-27.5)
Rocker Arm Valve Adjusting Locknuts, lb-ft (Nm) ............... 10.1-12.3 (13.7-16.7)
Valve Cover Retaining Nut Fasteners, lb-ft (Nm) ............... 5.1-7.2 (6.9-9.8)
Oil Pan Sump Drain Plug, lb-ft (Nm) ............... 36.2-43.4 (49.0-59.0)
Oil Pan Sump Perimeter Bolts, lb-ft (Nm) ............... 7.2-8.7 (9.8-11.8)
Idler Gear Shaft Bolts, lb-ft (Nm) ............... 16.6-20.3 (22.5-27.5)
Timing Gear Case Cover Fasteners, lb-ft (Nm) ............... 16.6-20.3 (22.5-27.5)
Fuel Injection Pump Drive Nut, lb-ft (Nm) ............... 43.4-50.6 (59.0-68.6)
Fuel Injection Pump Delivery Valve Holder lb-ft (Nm) ............... 25.3-28.9 (34.3-39.2)
Fuel Injection High Pressure Line Union Nuts, lb-ft (Nm) ............... 16.6-20.3 (22.5-27.5)
Fuel Injection Nozzle Holder Assembly Nut, lb-ft (Nm) ............... 36.2-43.4 (49.0-59.0)
Fuel Injection Nozzle Case Nut, lb-ft (Nm) ............... 25.3-28.9 (34.3-39.2)
Fuel Return Spill Pipe Line Joint Bolts, lb-ft (Nm) ............... 7.2-10.1 (9.8-13.7)
Glow Plug Assembly Screws, lb-ft (Nm) ............... 10.1-14.5 (13.7-19.6)
Oil Pressure Switch Sender Sensor, lb-ft (Nm) ............... 10.1-14.5 (13.7-19.6)
Water Temperature Switch Sensor Transmitter, lb-ft (Nm) ............... 14.5-21.7 (19.6-29.4)
Exhaust Manifold Securing Stud Nuts, lb-ft (Nm) ............... 16.6-20.3 (22.5-27.5)
Air Intake Intake Manifold Fastening Bolts, lb-ft (Nm) ............... 16.6-20.3 (22.5-27.5)
Starter Motor Securing Mounting Bolts, lb-ft (Nm) ............... 31.8-39.1 (43.1-53.0)
Alternator Pivot Mount Pin Long Bolt, lb-ft (Nm) ............... 16.6-20.3 (22.5-27.5)
Alternator Adjusting Brace Locking Bolt, lb-ft (Nm) ............... 11.6-14.5 (15.7-19.6)
Water Pump Assembly Sump Housing Bolts, lb-ft (Nm) ............... 7.2-8.7 (9.8-11.8)
Thermostat Housing Cover Screws, lb-ft (Nm) ............... 7.2-8.7 (9.8-11.8)

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