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Mitsubishi K3D Engine

The Mitsubishi K3D is a compact, vertical, water-cooled, 4-stroke, 3-cylinder-in-line diesel engine. Engineered for durability and high power-to-weight ratio, it features a swirl combustion chamber design which enhances fuel-air mixing efficiency and reduces operational noise. This engine series is widely deployed in small agricultural tractors (such as the Iseki TU160), mini-excavators (e.g., Bobcat X125), commercial lawnmowers (TORO 325D/324D), and localized generator sets.

Valve Configuration: Overhead Valve (OHV) pushrod-driven system configuration with valve guides integrated into the cylinder head assembly. Valves Per Cylinder: 2 valves per cylinder (1 intake, 1 exhaust). Bore: 73 mm (2.874 inches). Stroke: 78 mm (3.071 inches). Total Displacement: 0.979 liters (979 cc / 59.77 cubic inches). Compression Ratio: 23:1.

Fuel Injection Pump: High-pressure Bosch M type mini-pump assembly. Injection Nozzle: Throttle type nozzle matching the requirements of the high-compression swirl combustion chamber. Governor: Centrifugal flyweight type governor controlling fuel delivery curves across the RPM range. Fuel Specification: Standard automotive or industrial diesel fuel.

Lubrication System: Forced pressure lubrication system. Oil Pump Type: Trochoid type pump driven by the gear train. Filtration: Full-flow filtration using a replaceable element paper cartridge filter. Cooling System: Forced liquid cooling circulation. Coolant Pump: Centrifugal belt-driven water pump assembly mounted to the front gear case. Temperature Regulation: Wax-pellet type thermostat regulating optimal operating temperatures alongside a radiator unit and cooling fan assembly.

General Technical Data

Engine Specifications

Engine Model ............... Mitsubishi K3D
Engine Type ............... 4-cycle vertical inline 3-cylinder water-cooled diesel engine
Number of Cylinders ............... 3
Cylinder Arrangement ............... In-line vertical configuration
Combustion Chamber ............... Swirl chamber spherical pre-combustion system
Aspiration Type ............... Naturally aspirated
Valve Train Layout ............... Overhead valve driven via pushrods
Number of Valves per Cylinder ............... 2
Total Number of Valves ............... 6
Engine Bore, in (mm) ............... 2.874 (73.0)
Engine Stroke, in (mm) ............... 3.071 (78.0)
Displacement, cu.in (cc) ............... 59.77 (979)
Rated Power, hp (kW) ............... 21.0-22.0 (15.7-16.4)
Rated Speed, rpm ............... 2700-3200
Max Bare Power, hp (kW) ............... 22.0 (16.4) at 3200 rpm
Continuous Power, hp (kW) ............... 18.5 (13.8) at 3000 rpm
Peak Torque, lb-ft (Nm) ............... 38.3-40.5 (52.0-55.0)
Peak Torque Speed, rpm ............... 1600-1800
Low Idle Speed, rpm ............... 800-900
High Idle Speed, rpm ............... 3350-3450
Compression Ratio ............... 23.0:1
Firing Order ............... 1-3-2
Crankshaft Rotation Direction ............... Counterclockwise
Cylinder Block Material ............... High strength alloyed cast iron
Cylinder Head Material ............... Heavy duty cast iron alloy monoblock
Crankshaft Material ............... Forged steel alloy inductions hardened journals
Lubrication System ............... Full pressure trochoid pump force feed
Oil Pump Type ............... Trochoid type gear-driven assembly
Oil Filter Type ............... Full-flow paper element spin-on canister style
Cooling System ............... Forced circulation centrifugal impeller coolant pump
Water Pump Type ............... Belt-driven centrifugal impeller layout
Cooling Fan Blades ............... 4-blade high-flow push/pull layout
Air Cleaner Type ............... Dry element dual phase canister system
Electrical System ............... 12V
Alternator Output ............... 35A

Fuel System

Fuel Injection Pump Type ............... Bosch M inline monoblock multi plunger
Injection Pump Manufacturer ............... Diesel Kiki production assembly
Fuel Injection Nozzle Holder Model ............... ND-PFR3M multi unit block arrangement
Fuel Injection Nozzle Type ............... Throttle, self cleaning high atomization pintle device
Nozzle Part Model Number ............... DN12SD12A or DLLA155P15
Injection Opening Pressure, psi (bar) ............... 1706.8-1849.2 (117.7-127.5)
Static Injection Timing, degrees BTDC ............... 19.0-21.0
Governor Type ............... Centrifugal mechanical flyweight
Fuel Delivery Pump Type ............... Mechanical diaphragm lift
Maximum Fuel Lift Pump Height, ft (m) ............... 3.28 (1.0)
Fuel Lift Pump Delivery Pressure, psi (bar) ............... 2.84-4.26 (0.196-0.294)
Fuel Filter Classification ............... Spin-on canister with water sedimenter trap bowl
Fuel Overflow Valve Crack Pressure, psi (bar) ............... 14.2-21.3 (0.98-1.47)
Governor Spring Free Length, in (mm) ............... 2.441 (62.0)
Fuel Injection Pipe Outer Diameter, in (mm) ............... 0.236 (6.0)
Fuel Injection Pipe Inner Bore Diameter, in (mm) ............... 0.078 (2.0)
Fuel Injection Pipe Total Length, in (mm) ............... 15.748 (400.0)
Recommended Fuel Grade ............... Diesel fuel oil ASTM D975 Number 2-D

Dimensions and Weight

Overall Length, in (mm) ............... 19.5 (495)
Overall Width, in (mm) ............... 16.6 (425)
Overall Height, in (mm) ............... 21.6 (550)
Dry Weight, lbs (kg) ............... 200 (91.0)
Operating Weight, lbs (kg) ............... 216 (98)

Maintenance Data

Service Information

Compression Pressure, Standard, psi (MPa) ............... 426.7 (2.94)
Compression Pressure, Limit, psi (MPa) ............... 341.3 (2.35)
Compression Variation Between Cylinders, psi (MPa) ............... 35.5 (0.245)
Oil Pressure at Rated RPM, psi (bar) ............... 42.6-56.8 (2.94-3.92)
Oil Pressure at Idle RPM, psi (bar) ............... 11.3 (0.78)
Oil Pressure Relief Valve, psi (bar) ............... 56.8-71.1 (3.92-4.90)
Thermostat Start To Open Temperature, F (C) ............... 165.2-172.4 (74.0-78.0)
Thermostat Fully Open Temperature, F (C) ............... 194.0 (90.0)
Radiator Cap Pressure Setting, psi (bar) ............... 12.8 (0.88)
Alternator Belt Deflection, in (mm) ............... 0.275-0.472 (7.0-12.0)
Intake Valve Clearance, in (mm) ............... 0.010 (0.25)
Exhaust Valve Clearance, in (mm) ............... 0.010 (0.25)

Engine Oil and Coolant

Engine Oil Type .................. SAE 30W, SAE 10W-30, or 15W-40
API Service Classifications ......................... CD, CE, CF, CF-4, or CG-4
Engine Oil Capacity, High Level, qt (L) ............... 4.22 (4.0)
Engine Oil Capacity, Low Level, qt (L) ............... 2.64 (2.5)
Engine Oil Capacity with Filter, qt (L) ............... 4.54 (4.3)
Cooling System Capacity, qt (L) ............... 2.11 (2.0)
Coolant Capacity with Expansion Bottle, qt (L) ............... 4.75 (4.5)

Service Intervals

Change oil and filter ............... Every 100 hours
Inspect air cleaner ............... Every 50 hours
Replace air cleaner ............... Every 1000 hours
Replace fuel filter ............... Every 200 hours
Valve clearance adjustment ............... Every 400 hours
Fuel system inspection ............... Every 600 hours
Change coolant ............... Every 1000 hours
Compression test ............... Every 800 hours
Clean radiator core ............... Every 250 hours
Inspect belt tension ............... Every 250 hours

Service Specifications

Cylinder Bore Inside Diameter, in (mm) ............... 2.8740 (73.00)
Cylinder Bore Maximum Diameter, in (mm) ............... 2.8751 (73.03)
Cylinder Bore Out-of-Round, in (mm) ............... 0.0003 (0.01)
Cylinder Block Face Distortion Flatness, in (mm) ............... 0.0019 (0.05)
Cylinder Head Deck Face Surface Flatness, in (mm) ............... 0.0019 (0.05)
Crankshaft Main Journal Diameter, in (mm) ............... 1.6535 (42.00)
Crankshaft Main Journal Out-of-Round, in (mm) ............... 0.0003 (0.01)
Crankpin Journal Diameter, in (mm) ............... 1.4960 (38.00)
Crankpin Journal Out-of-Round, in (mm) ............... 0.0003 (0.01)
Connecting Rod Axial End Play, in (mm) ............... 0.0039-0.0137 (0.100-0.350)
Main Bearing Journal Oil Clearance, in (mm) ............... 0.0011-0.0027 (0.030-0.072)
Connecting Rod Journal Oil Clearance, in (mm) ............... 0.0009-0.0024 (0.025-0.062)
Piston Skirt Outer Diameter, in (mm) ............... 2.8716 (73.12)
Piston to Cylinder Wall Clearance, in (mm) ............... 0.0019-0.0031 (0.050-0.080)
Piston Pin Boss Hole Inside Diameter, in (mm) ............... 0.8267-0.8271 (21.000-21.009)
Piston Pin Outer Diameter, in (mm) ............... 0.8265-0.8267 (20.994-21.000)
Piston Pin to Small End Bushing Clearance, in (mm) ............... 0.0003-0.0009 (0.010-0.025)
Top Ring Groove Width, in (mm) ............... 0.0787 (2.00)
Second Ring Groove Width, in (mm) ............... 0.0787 (2.00)
Oil Ring Groove Width, in (mm) ............... 0.1574 (4.00)
Top Ring Groove Side Clearance, in (mm) ............... 0.0023-0.0039 (0.060-0.100)
Second Ring Groove Side Clearance, in (mm) ............... 0.0019-0.0035 (0.050-0.090)
Oil Ring Groove Side Clearance, in (mm) ............... 0.0007-0.0021 (0.020-0.055)
Top Ring End Gap, in (mm) ............... 0.0059-0.0118 (0.150-0.300)
Second Ring End Gap, in (mm) ............... 0.0059-0.0118 (0.150-0.300)
Oil Ring End Gap, in (mm) ............... 0.0078-0.0157 (0.200-0.400)
Intake Valve Stem Outer Diameter, in (mm) ............... 0.2582-0.2590 (6.560-6.575)
Exhaust Valve Stem Outer Diameter, in (mm) ............... 0.2562-0.2574 (6.510-6.540)
Valve Guide Tube Bore Inside Diameter, in (mm) ............... 0.2598-0.2606 (6.600-6.620)
Valve Guide Tube Outer Diameter, in (mm) ............... 0.4334-0.4340 (11.010-11.025)
Valve Guide Bore Inside Diameter, in (mm) ............... 0.4311-0.4320 (10.950-10.975)
Intake Valve Stem to Guide Clearance, in (mm) ............... 0.0009-0.0023 (0.025-0.060)
Exhaust Valve Stem to Guide Clearance, in (mm) ............... 0.0023-0.0043 (0.060-0.110)
Intake Valve Seat Bore Outer Diameter, in (mm) ............... 1.3385-1.3393 (34.000-34.025)
Exhaust Valve Seat Bore Outer Diameter, in (mm) ............... 1.1811-1.1819 (30.000-30.025)
Valve Face Seating Width, in (mm) ............... 0.0472-0.0590 (1.20-1.50)
Valve Seating Angle, degrees ............... 45
Valve Spring Free Length, in (mm) ............... 1.4566 (37.00)
Camshaft Journal Outer Diameter (Front), in (mm) ............... 1.4960-1.4968 (38.000-38.020)
Camshaft Journal Outer Diameter (Center), in (mm) ............... 1.4566-1.4574 (37.000-37.020)
Camshaft Journal Outer Diameter (Rear), in (mm) ............... 1.4173-1.4181 (36.000-36.020)
Cam Lobe Height (Intake), in (mm) ............... 1.2244 (31.10)
Cam Lobe Height (Exhaust), in (mm) ............... 1.2283 (31.20)
Camshaft Journal Radial Clearance, in (mm) ............... 0.0019-0.0035 (0.050-0.090)
Rocker Arm Shaft Outer Diameter, in (mm) ............... 0.4716-0.4721 (11.979-11.991)
Rocker Arm Bushing Bore Inside Diameter, in (mm) ............... 0.4724-0.4735 (12.000-12.027)
Tappet Valve Lifter Outer Diameter, in (mm) ............... 0.7062-0.7070 (17.940-17.960)
Idler Gear Bushing Bore Inside Diameter, in (mm) ............... 0.7874-0.7885 (20.000-20.027)
Idler Gear Spindle Shaft Outer Diameter, in (mm) ............... 0.7861-0.7869 (19.967-19.980)

Tightening Torques

Cylinder Head Bolts, lb-ft (Nm) ............... 54.2-57.8 (73.5-78.5)
Main Bearing Cap Bolts, lb-ft (Nm) ............... 36.1-39.7 (49.0-54.0)
Connecting Rod Cap Bolts, lb-ft (Nm) ............... 23.1-26.0 (31.4-35.3)
Crankshaft Front Pulley Center Nut, lb-ft (Nm) ............... 72.3-79.5 (98.0-107.8)
Flywheel to Crankshaft Rear Flange Mount Bolts, lb-ft (Nm) ............... 43.3-47.0 (58.8-63.7)
Camshaft Thrust Plate Retaining Screws, lb-ft (Nm) ............... 14.4-18.0 (19.6-24.5)
Rocker Arm Shaft Support Bracket Nut, lb-ft (Nm) ............... 21.6-25.3 (29.4-34.3)
Cylinder Head Valve Valve Cover Cap Nuts, lb-ft (Nm) ............... 4.3-5.7 (5.9-7.8)
Oil Pump Assembly Housing Outer Mount Bolts, lb-ft (Nm) ............... 8.6-11.5 (11.7-15.7)
Oil Sump Pan Perimeter Flange Hex Fasteners, lb-ft (Nm) ............... 7.2-8.6 (9.8-11.7)
Oil Sump Drain Plug Hex Head Fitting Fluid Drain, lb-ft (Nm) ............... 25.3-32.5 (34.3-44.1)
Timing Gear Case Cover Outer Fasteners, lb-ft (Nm) ............... 14.4-18.0 (19.6-24.5)
Water Pump Body to Engine Block Fasteners, lb-ft (Nm) ............... 14.4-18.0 (19.6-24.5)
Coolant Thermostat Housing Mount Bolts, lb-ft (Nm) ............... 14.4-18.0 (19.6-24.5)
Intake Manifold Pipe to Cylinder Head Cast Ports, lb-ft (Nm) ............... 14.4-18.0 (19.6-24.5)
Exhaust Manifold Heat Shield Stud Lock Nuts, lb-ft (Nm) ............... 18.0-21.6 (24.5-29.4)
Fuel Injection Pump Deck Base Alignment Mounting Nuts, lb-ft (Nm) ............... 14.4-18.0 (19.6-24.5)
Fuel Injection Pipe Union Swivel Delivery Joint Nut Ports, lb-ft (Nm) ............... 18.0-21.6 (24.5-29.4)
Fuel Injector Holder Nozzle Body Outer Assembly, lb-ft (Nm) ............... 43.3-50.6 (58.8-68.6)
Fuel Injector Nozzle Cap Retaining Shell Internal Nut, lb-ft (Nm) ............... 28.9-36.1 (39.2-49.0)
Fuel Leak-off Overflow Pipe Banjo Fitting Screw, lb-ft (Nm) ............... 18.0-21.6 (24.5-29.4)
Glow Plug Assembly Main Mechanical Hex Shell, lb-ft (Nm) ............... 10.8-14.4 (14.7-19.6)
Glow Plug Electrical Power Supply Ribbon Small Nuts, lb-ft (Nm) ............... 1.0-1.5 (1.3-2.0)
Oil Pressure Sensor Indicator Unit Screw, lb-ft (Nm) ............... 10.8-14.4 (14.7-19.6)
Water Temperature Thermistor Sending Core Screw, lb-ft (Nm) ............... 14.4-18.0 (19.6-24.5)
Starter Motor Housing Structural Flange Mount Screws, lb-ft (Nm) ............... 28.9-36.1 (39.2-49.0)
Alternator Pivoting Mounting Main Hinge Anchor Bolt, lb-ft (Nm) ............... 21.6-28.9 (29.4-39.2)
Alternator Adjusting Link Slide Locking Guide Bolt, lb-ft (Nm) ............... 14.4-18.0 (19.6-24.5)
Fan Drive Pulley Segment Hub Flange Fasteners, lb-ft (Nm) ............... 7.2-10.1 (9.8-13.7)

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• Mitsubishi Engines Specs
  
• Mitsubishi K3A Specs
  
• Mitsubishi K3B Specs
  
• Mitsubishi K3C Specs
  
• Mitsubishi KE70 Specs
  
• Mitsubishi KE75 Specs
  

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