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Mitsubishi K4E Engine

The Mitsubishi K4E engine is a vertical, water-cooled, 4-stroke, 4-cylinder inline diesel engine engineered by Mitsubishi Heavy Industries for high durability and performance in a compact footprint. Known for its reliability and smooth power delivery, it is extensively utilized as a primary power plant in light-to-medium industrial and construction machinery. Common applications include mini-excavators (such as models from Hanix, Peljob, Airman, and Hitachi), wheel loaders, skid steers, marine propulsion systems, agricultural tractors, and stationary generator sets.

The cylinder head utilizes an overhead valve (OHV) configuration, featuring 2 valves per cylinder (1 intake valve and 1 exhaust valve), totaling 8 valves across the entire engine block. Valve actuation is managed via a gear-driven camshaft operating conventional pushrods and rocker arm assemblies. Total Engine Displacement: 1.415 Liters (1,415 cc). Cylinder Bore: 76 mm. Piston Stroke: 78 mm.

The fuel system relies on a mechanical indirect injection (IDI) design using swirl or pre-combustion chambers to ensure thorough air-fuel mixing and lower mechanical stress. Fuel is drawn from the supply tank through a primary fuel filter and water separator, then pressurized by a high-precision, multi-plunger mechanical inline injection pump. The injection pump delivers fuel through high-pressure steel lines to the individual throttle or pintle-type injection nozzles, atomizing the diesel directly into the pre-combustion chambers. Engine speed regulation is controlled via an integrated mechanical governor assembly attached directly to the injection pump control rack.

Lubrication is managed via a full-pressure, wet-sump system. A trochoid-type oil pump driven directly by the crankshaft draws oil from the oil pan and distributes it under pressure through an integrated full-flow oil filter to the main bearings, connecting rod journals, camshaft bearings, and overhead rocker assemblies. Splash lubrication supplies oil to the cylinder walls and piston pins.

The engine employs a pressurized, closed-loop water-cooled system utilizing forced circulation. A belt-driven centrifugal water pump continuously circulates coolant through the internal cylinder block jackets and cylinder head passages. Temperature regulation is maintained via a wax-pellet type thermostat that routes coolant to an external radiator for heat dissipation based on operating demands.

General Technical Data

Engine Specifications

Engine Model ............... Mitsubishi K4E
Engine Type ............... 4-cycle inline 4-cylinder indirect injection liquid-cooled diesel
Number of Cylinders ............... 4
Cylinder Arrangement ............... In-line
Engine Bore, in (mm) ............... 2.99 (76.0)
Engine Stroke, in (mm) ............... 3.07 (78.0)
Displacement, cu.in (L) ............... 86.3 (1.415)
Rated Engine Power, hp (kW) ............... 26.0-31.0 (19.4-22.8)
Rated Engine Speed, rpm ............... 2700-3000
Peak Torque ............... 58.0-62.0 lb-ft (78.6-84.1 Nm) at 1800 rpm
Idle Speed ............... 800-900 rpm
Aspiration Type ............... Naturally Aspirated
Operating Speed ............... 2700 rpm
Compression Ratio ............... 22.0:1-23.0:1
Firing Order ............... 1-3-4-2
Cylinder Block Type ............... Cast iron
Cylinder Head Type ............... Cast iron
Lubrication System ............... Full-pressure forced lubrication by trochoid pump
Oil Pump Type ............... Gear-driven trochoid pump
Oil Filter Type ............... Full-flow, spin-on cartridge type
Cooling System ............... Liquid-cooled with forced circulation flow
Water Pump Type ............... Belt-driven, centrifugal impeller type
Air Cleaner Type ............... Dry polyurethane element dual-stage element type
Starting System ............... Electric starter motor with glow plugs preheating
Electrical System ............... 12V

Fuel System

Fuel Injection Pump Type ............... Bosch M type in-line mini pump unit
Governor Type ............... Mechanical centrifugal all-speed type system
Fuel Injector Type ............... Throttle type nozzle system configuration
Injection Pressure, psi (bar) ............... 1706-1849 (118.0-127.5)
Injection Timing, deg BTDC ............... 18-20
Fuel Transfer Pump Type ............... Mechanical diaphragm type pump unit
Fuel Filter Type ............... Spin-on element paper cartridge type filtration
Fuel Feed System ............... Mechanical lift pump with manual priming lever
Fuel Return System ............... Overflow pipe line connected to fuel tank
Maximum Fuel Suction Head, in (mm) ............... 39.4 (1000.0)
Maximum Fuel Return Restriction, psi (bar) ............... 2.9 (0.2)
Recommended Fuel Type ............... Diesel fuel oil number 2-D premium

Dimensions and Weight

Overall Length, in (mm) ............... 22.8 (580)
Overall Width, in (mm) ............... 18.5 (470)
Overall Height, in (mm) ............... 23.2 (590)
Dry Weight, lbs (kg) ............... 320 (145)

Maintenance Data

Service Information

Cylinder Compression Pressure, Standard, psi (bar) ............... 426.7 (29.4)
Cylinder Compression Pressure, Limit, psi (bar) ............... 369.8 (25.5)
Compression Variation Between Cylinders, psi (bar) ............... 35.6 (2.5)
Oil Pressure at Idle Speed, psi (bar) ............... 14.2 (1.0)
Oil Pressure at Rated Speed, psi (bar) ............... 42.6-56.8 (3.0-3.9)
Radiator Cap Pressure, psi (bar) ............... 12.8 (0.9)
Thermostat Opening Temperature, F (C) ............... 169.0 (76.1)
Thermostat Full Open Temperature, F (C) ............... 194.0 (90.0)
Coolant Temperature Max Limit, F (C) ............... 212.0 (100.0)
Fan Belt Deflection under Force, in (mm) ............... 0.39-0.47 (10.0-12.0)
Intake Valve Clearance, Cold, in (mm) ............... 0.010 (0.25)
Exhaust Valve Clearance, Cold, 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
Engine Oil Capacity with Filter, qt (L) ............... 5.8 (5.5)
Engine Oil Capacity with Filter, qt (L) ............... 5.0 (4.7)
Coolant Capacity, qt (L) ............... 6.3 (6.0)

Service Intervals

Change oil and filter ............... Every 200 hours
Inspect air cleaner ............... Every 100 hours
Replace air cleaner ............... Every 500 hours
Replace fuel filter ............... Every 400 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 100 hours

Service Specifications

Cylinder Bore Inside Diameter, in (mm) ............... 2.9921-2.9933 (76.000-76.030)
Cylinder Bore Wear Maximum, in (mm) ............... 2.9992 (76.180)
Cylinder Bore Taper and Out of Round, in (mm) ............... 0.0004 (0.010)
Cylinder Block Top Surface Flatness, in (mm) ............... 0.0019 (0.050)
Cylinder Head Bottom Surface Flatness, in (mm) ............... 0.0019 (0.050)
Crankshaft Main Journal O.D, in (mm) ............... 2.0461-2.0469 (51.970-51.990)
Crankpin Standard O.D, in (mm) ............... 1.6917-1.6925 (42.970-42.990)
Main Bearing Oil Clearance, in (mm) ............... 0.0012-0.0028 (0.030-0.070)
Connecting Rod Bearing Clearance, in (mm) ............... 0.0012-0.0028 (0.030-0.070)
Connecting Rod Journal Width, in (mm) ............... 0.8661 (22.000)
Crankshaft End Play, in (mm) ............... 0.0020-0.0098 (0.050-0.250)
Piston Outer Diameter, in (mm) ............... 2.9901-2.9913 (75.950-75.980)
Piston to Cylinder Bore Clearance, in (mm) ............... 0.0008-0.0020 (0.020-0.050)
Piston Pin Outer Diameter, in (mm) ............... 0.8661-0.8665 (22.000-22.010)
Piston Pin Small End Bushing Clearance, in (mm) ............... 0.0004-0.0008 (0.010-0.020)
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) ............... 0.0059-0.0118 (0.150-0.300)
Second Ring End Gap, in (mm) ............... 0.0059-0.0118 (0.150-0.300)
Oil Ring End Gap, in (mm) ............... 0.0079-0.0157 (0.200-0.400)
Intake Valve Stem Outer Diameter, in (mm) ............... 0.2598-0.2604 (6.600-6.615)
Exhaust Valve Stem Outer Diameter, in (mm) ............... 0.2591-0.2596 (6.580-6.595)
Valve Guide Inside Diameter, in (mm) ............... 0.2606-0.2612 (6.620-6.635)
Intake Valve Stem to Guide Clearance, in (mm) ............... 0.0008-0.0020 (0.020-0.050)
Exhaust Stem to Guide Clearance, in (mm) ............... 0.0016-0.0028 (0.040-0.070)
Intake Valve Seat Bore Inside Diameter, in (mm) ............... 1.2598-1.2608 (32.000-32.025)
Exhaust Valve Seat Bore Inside Diameter, in (mm) ............... 1.1417-1.1427 (29.000-29.025)
Intake Valve Seat Outer Diameter, in (mm) ............... 1.2638-1.2646 (32.100-32.120)
Exhaust Valve Seat Outer Diameter, in (mm) ............... 1.1457-1.1465 (29.100-29.120)
Valve Face Angle, deg ............... 45
Valve Seat Angle, deg ............... 45
Valve Seat Width, in (mm) ............... 0.0512-0.0709 (1.300-1.800)
Valve Spring Free Length, in (mm) ............... 1.4803 (37.600)
Camshaft Journal Outer Diameter, in (mm) ............... 1.6917-1.6925 (42.970-42.990)
Cam Lobe Height (Intake), in (mm) ............... 1.3406 (34.050)
Cam Lobe Height (Exhaust), in (mm) ............... 1.3406 (34.050)
Camshaft Journal Oil Clearance, in (mm) ............... 0.0020-0.0035 (0.050-0.090)
Camshaft End Play, in (mm) ............... 0.0020-0.0098 (0.050-0.250)
Rocker Shaft Outer Diameter, in (mm) ............... 0.4685-0.4693 (11.900-11.920)
Rocker Arm Bushing Inside Diameter, in (mm) ............... 0.4705-0.4717 (11.950-11.980)
Rocker Arm Bushing to Shaft Clearance, in (mm) ............... 0.0012-0.0031 (0.030-0.080)
Tappet Body Bore Inside Diameter, in (mm) ............... 0.7874-0.7882 (20.000-20.021)
Tappet Outer Stem Diameter, in (mm) ............... 0.7846-0.7858 (19.930-19.960)
Tappet Stem to Cylinder Block Bore Clearance, in (mm) ............... 0.0059 (0.150)
Idler Gear Bushing Inside Diameter, in (mm) ............... 1.3386-1.3398 (34.000-34.030)
Idler Gear Shaft Outer Diameter, in (mm) ............... 1.3358-1.3370 (33.930-33.960)
Idler Gear Bushing to Shaft Clearance, in (mm) ............... 0.0016-0.0039 (0.040-0.100)

Tightening Torques

Cylinder Head Bolts, lb-ft (Nm) ............... 54.2-57.9 (73.5-78.5)
Main Bearing Cap Bolts, lb-ft (Nm) ............... 36.2-39.8 (49.0-54.0)
Connecting Rod Cap Nut, lb-ft (Nm) ............... 23.1-26.8 (31.4-36.3)
Flywheel Bolt, lb-ft (Nm) ............... 61.5-68.7 (83.4-93.2)
Crankshaft Pulley Center Bolt, lb-ft (Nm) ............... 72.3-79.6 (98.0-107.9)
Rocker Arm Shaft Bracket Bolt, lb-ft (Nm) ............... 10.8-14.5 (14.7-19.6)
Rocker Arm Lock Nut, lb-ft (Nm) ............... 8.7-11.6 (11.8-15.7)
Timing Gear Case Cover Mounting Bolt, lb-ft (Nm) ............... 14.5-18.1 (19.6-24.5)
Oil Pan Drain Plug, lb-ft (Nm) ............... 28.9-36.2 (39.2-49.0)
Oil Pan Mounting Perimeter Bolt, lb-ft (Nm) ............... 7.2-10.8 (9.8-14.7)
Fuel Injection Nozzle Retaining Nut, lb-ft (Nm) ............... 25.3-28.9 (34.3-39.2)
Fuel Injection Pump Delivery Valve Holder, lb-ft (Nm) ............... 28.9-32.5 (39.2-44.1)
Fuel High Pressure Line Union Nut, lb-ft (Nm) ............... 18.1-21.7 (24.5-29.4)
Fuel Injection Pump Mounting Nut, lb-ft (Nm) ............... 14.5-18.1 (19.6-24.5)
Glow Plug Terminal Connection Hex Nut, lb-ft (Nm) ............... 1.0-1.5 (1.4-2.0)
Glow Plug Body, lb-ft (Nm) ............... 10.8-14.5 (14.7-19.6)
Oil Pressure Switch, lb-ft (Nm) ............... 10.8-14.5 (14.7-19.6)
Water Temperature Senso, lb-ft (Nm) ............... 14.5-21.7 (19.6-29.4)
Intake Manifold Mounting Flange Bolt, lb-ft (Nm) ............... 10.8-14.5 (14.7-19.6)
Exhaust Manifold Mounting Flange Nut, lb-ft (Nm) ............... 14.5-18.1 (19.6-24.5)
Starter Motor Mounting Flange Bolt, lb-ft (Nm) ............... 28.9-36.2 (39.2-49.0)
Alternator Pivot And Tensioner Bolt, lb-ft (Nm) ............... 14.5-21.7 (19.6-29.4)
Water Pump Mounting Housing Bolt, lb-ft (Nm) ............... 10.8-14.5 (14.7-19.6)
Thermostat Housing Attachment Fastener, lb-ft (Nm) ............... 10.8-14.5 (14.7-19.6)
Front Plate Engine Block Attachment Bolt, lb-ft (Nm) ............... 14.5-18.1 (19.6-24.5)
Flywheel Housing Block Attachment Bolt, lb-ft (Nm) ............... 28.9-36.2 (39.2-49.0)
Rear Oil Seal Case Retaining Bolt, lb-ft (Nm) ............... 7.2-10.8 (9.8-14.7)
Valve Cover Cap Nut, lb-ft (Nm) ............... 3.6-5.1 (4.9-6.9)

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• Mitsubishi Engines Specs
  
• Mitsubishi K4C Specs
  
• Mitsubishi K4D Specs
  
• Mitsubishi K4F Specs
  
• Mitsubishi K4M Specs
  
• Mitsubishi K4N Specs
  

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