________________________________________________________________________________

Doosan D34P Engine

The Doosan D34P is an industrial-grade, in-line 4-cylinder, 4-cycle water-cooled diesel engine engineered for heavy-duty applications, including Doosan Forklifts and Bobcat loaders. Designed to comply with stringent EPA Tier 4 Final and Stage V emissions regulations, it integrates high-pressure common-rail technology with an optimized electronic control unit (ECU) governor. The engine delivers robust low-end torque, high fuel efficiency, and long-term durability. Maintenance requirements are streamlined through extended service intervals and a non-DPF (Diesel Particulate Filter) aftertreatment strategy that instead utilizes a Diesel Oxidation Catalyst (DOC) and Selective Catalytic Reduction (SCR) system.

The cylinder head utilizes an overhead valve (OHV) arrangement featuring 4 valves per cylinder (2 intake valves and 2 exhaust valves). Valvetrain clearance is regulated automatically via a Hydraulic Valve Lash Adjuster (HLA) system. This design provides maintenance-free operation by eliminating the requirement for manual mechanical valve lash adjustments during routine service intervals. The engine features a total displacement of 3.409 liters. The precise internal cylinder dimensions are specified with a cylinder bore diameter of 98 mm and a piston stroke length of 113 mm.

Fuel System: Combustion relies on an electronically controlled, high-pressure Common-Rail Direct Injection (CRDI) system. High pressure is generated by a Delphi DFP 4.2 (or Bosch equivalent) injection pump and delivered directly to the cylinders through precision multi-hole injection nozzles. The system is managed dynamically by the engine ECU to optimize injection timing, fuel quantity, and multi-stage injection events. Operating Pressures: Fuel inlet feed pressure must maintain a range between 0.5 and 1.5 bar, with fuel return line pressure operating at 1.2 bar.

Lubrication is managed via a fully forced pressure feed system driven by a crankshaft-mounted gear-type oil pump. Oil filtration is handled through a replaceable, full-flow spin-on cartridge filter. Operational Pressure: Minimum allowable pressure at engine idle speed is 100 kPa. Minimum pressure at governed rated speed is 250 kPa. The cooling system is a freshwater, forced-circulation type designed to maintain optimal thermal equilibrium under variable loads. Coolant movement is driven by a centrifugal water pump driven by the engine accessory belt.

General Technical Data

Engine Specifications

Engine Model ............... Doosan D34
Engine Type ............... 4-cycle inline 4-cylinder direct injection liquid-cooled diesel
Number of Cylinders ............... 4
Cylinder Arrangement ............... In-line
Engine Bore, in (mm) ............... 3.86 (98.0)
Engine Stroke, in (mm) ............... 4.45 (113.0)
Displacement, cu.in (L) ............... 208.0 (3.409)
Rated Engine Power, hp (kW) ............... 74.0-135.1 (55.0-100.7)
Rated Engine Speed, rpm ............... 2200-2600
Peak Torque ............... 330-500 Nm (243.4-368.8 lb-ft) at 1400-1600 rpm
Idle Speed ............... 800 rpm
Aspiration Type ............... Turbocharged and Intercooled
Operating Speed, rpm ............... 2400-2600
Compression Ratio ............... 17.0:1-18.0:1
Firing Order ............... 1-3-4-2
Rotation Direction ............... Counterclockwise viewed from flywheel end
Number of Valves per Cylinder ............... 4 (2 intake, 2 exhaust)
Cylinder Block Type ............... Cast iron linerless
Cylinder Head Type ............... Cast iron over head valve
Lubrication System ............... Fully forced pressure feed type
Oil Pump Type ............... Gear type driven by crankshaft
Oil Filter Type ............... Full flow, cartridge type spin-on
Cooling System ............... Liquid-cooled fresh water forced circulation
Water Pump Type ............... Belt-driven, centrifugal
Emissions Standards ............... EPA Tier 4 Final / EU Stage V
Air Cleaner Type ............... Dry dual-stage element
Starting System ............... Electric Starter Motor
Electrical System ............... 12V

Fuel System

Injection Pump Model ............... Delphi DFP 4.2
Fuel Injection Type ............... High pressure common rail system Bosch
Maximum Injection Pressure, bar (psi) ............... 1800.0 (26106.8)
Speed Governor Type ............... Electronic Control Unit ECU
Fuel Feed Pump Requirement ............... Integrated high pressure pump delivery
Injection Nozzle Type ............... Multi-hole electro-injector type
Primary Fuel Filter Type ............... Full flow cartridge element type
Fuel Water Separator Fitting ............... Integrated with primary element water sensor
Approved Fuel Specification Grade ............... EN590 Ultra-Low Sulfur Diesel fuel only
Fuel Delivery Pressure Range, bar (psi) ............... 3.5-5.0 (50.7-72.5)
Maximum Permissible Fuel Temperature, C (F) ............... 70.0 (158.0)
Low Pressure Fuel Circuit Minimum Pressure, bar (psi) ............... 2.0 (29.0)
High Pressure Fuel Rail Leak Threshold, bar (psi) ............... 1900.0 (27557.2)
Fuel Filter Nominal Filtration Rating, micron ............... 2.0-5.0
Fuel Injection Timing Control Method ............... Electronic map via engine ECU
Cold Start Preheating Device Type ............... High capacity cylinder glow plugs
Glow Plug Current Draw, A ............... 15.0-20.0

Dimensions and Weight

Bare Engine Length, in (mm) ............... 27.6 (700)
Bare Engine Width, in (mm) ............... 22.8 (580)
Bare Engine Height, in (mm) ............... 30.3 (770)
Industrial Powerpack Unit Length, in (mm) ............... 35.3 (895)
Industrial Powerpack Unit Width, in (mm) ............... 25.8 (655)
Industrial Powerpack Unit Height with DOC and Fan, in (mm) ............... 31.6 (805)
Powerpack Envelope Height with DOC and SCR up to 110hp, in (mm) ............... 39.1 (990)
Powerpack Envelope Height with DOC and SCR over 110hp, in (mm) ............... 39.6 (1005)
Powerpack Envelope Width with DOC and SCR over 110hp, in (mm) ............... 27.4 (695)
Open Power Unit OPU Vertical Height Total, in (mm) ............... 55.9 (1420)
Dry Weight Bare Base Engine, lbs (kg) ............... 738 (335)
Dry Weight Config with Aftertreatment Assembly, lbs (kg) ............... 1022.9 (464)
Dry Weight Fully Equipped Industrial Powerpack, lb (kg) ............... 1267.6 (575)

Maintenance Data

Service Information

Oil Pressure at Idle Speed, bar (psi) ............... 1.0-1.5 (14.5-21.7)
Oil Pressure at Rated Speed, bar (psi) ............... 3.0-4.5 (43.5-65.2)
Turbocharger Boost Pressure, bar (psi) ............... 1.2-1.6 (17.4-23.2)
Maximum Oil Operating Temperature, C (F) ............... 115.0 (239.0)
Coolant Thermostat Opening Temperature, C (F) ............... 82.0 (179.6)
Coolant Thermostat Full Open Temperature, C (F) ............... 95.0 (203.0)

Engine Oil and Coolant

Engine Oil Type .................. SAE 5W-30, SAE 10W-30, or 10W-40
API Service Classifications ......................... CI-4 or CJ-4
Engine Oil Capacity with Filter, qt (L) ............... 9.09 (8.6)
Engine Oil Capacity (Minimum Level), qt (L) ............... 6.34 (6.0)
Coolant Capacity (Engine Only), qt (L) ............... 6.87 (6.5)
Coolant Capacity with Radiator, qt (L) ............... 14.79 (14.0)

Service Intervals

Change oil and filter ............... Every 500 hours
Inspect air cleaner ............... Every 250 hours
Replace air cleaner ............... Every 1000 hours
Replace fuel filter ............... Every 500 hours
Valve clearance adjustment ............... Every 1000 hours
Fuel system inspection ............... Every 1000 hours
Change coolant ............... Every 2000 hours
Compression test ............... Every 1000 hours
Clean radiator core ............... Every 250 hours
Inspect belt tension ............... Every 250 hours

Service Specifications

Cylinder Bore Inner Diameter, in (mm) ............... 3.8583 (98.000) to 3.8591 (98.022)
Cylinder Bore Maximum Out of Round, in (mm) ............... 0.0006 (0.015)
Connecting Rod Small End Bushing I.D, in (mm) ............... 0.0004 (0.010) to 0.0011 (0.028)
Crankshaft Main Bearing Journal O.D, in (mm) ............... 3.1496 (80.000) to 3.1504 (80.020)
Crankpin Journal Diameter, in (mm) ............... 2.4409 (62.000) to 2.4417 (62.018)
Crankshaft Main Bearing Clearance, in (mm) ............... 0.0016 (0.040) to 0.0035 (0.090)
Connecting Rod Bearing Clearance, in (mm) ............... 0.0014 (0.035) to 0.0033 (0.085)
Crankshaft Axial End Play, in (mm) ............... 0.0039 (0.100) to 0.0118 (0.300)
Crankshaft Main Bearing Bore I.D, in (mm) ............... 3.3465 (85.000) to 3.3473 (85.022)
Piston Skirt Outside Diameter, in (mm) ............... 3.8543 (97.900) to 3.8551 (97.920)
Piston to Cylinder Wall Clearance, in (mm) ............... 0.0031 (0.080) to 0.0048 (0.122)
Piston Pin Bore Inner Diameter, in (mm) ............... 1.3386 (34.002) to 1.3391 (34.012)
Piston Pin Outside Diameter, in (mm) ............... 1.3382 (33.990) to 1.3385 (33.998)
Piston Pin to Small End Bushing Clearance, in (mm) ............... 0.0004 (0.010) to 0.0010 (0.025)
Top Piston Ring End Gap, in (mm) ............... 0.0098 (0.250) to 0.0157 (0.400)
Second Ring End Gap, in (mm) ............... 0.0197 (0.500) to 0.0276 (0.700)
Oil Ring End Gap, in (mm) ............... 0.0098 (0.250) to 0.0197 (0.500)
Top Ring Groove Side Clearance, in (mm) ............... 0.0035 (0.090) to 0.0051 (0.130)
Second Ring Groove Side Clearance, in (mm) ............... 0.0020 (0.050) to 0.0035 (0.090)
Oil Ring Groove Side Clearance, in (mm) ............... 0.0012 (0.030) to 0.0028 (0.070)
Cylinder Head Deck Lower Surface Flatness, in (mm) ............... 0.0020 (0.050)
Cylinder Block Main Deck Flatness, in (mm) ............... 0.0020 (0.050)
Intake Valve Guide Inner Diameter, in (mm) ............... 0.2756 (7.000) to 0.2764 (7.020)
Exhaust Valve Guide Inner Diameter, in (mm) ............... 0.2756 (7.000) to 0.2764 (7.020)
Intake Valve Stem Outside Diameter, in (mm) ............... 0.2736 (6.950) to 0.2744 (6.970)
Exhaust Valve Stem Outside Diameter, in (mm) ............... 0.2724 (6.920) to 0.2732 (6.940)
Intake Valve Stem to Guide Clearance, in (mm) ............... 0.0012 (0.030) to 0.0028 (0.070)
Exhaust Valve Stem to Guide Clearance, in (mm) ............... 0.0024 (0.060) to 0.0039 (0.100)
Intake Valve Head Margin Thickness, in (mm) ............... 0.0394 (1.000)
Exhaust Valve Head Margin Thickness, in (mm) ............... 0.0394 (1.000)
Intake Valve Seat Angle, deg ............... 45.0
Exhaust Valve Seat Angle, deg ............... 45.0
Valve Spring Free Length, in (mm) ............... 1.9291 (49.000)
Camshaft Bushing Inner Diameter, in (mm) ............... 2.1260 (54.000) to 2.1276 (54.040)
Cam Lobe Height (Intake), in (mm) ............... 1.4567 (37.000)
Cam Lobe Height (Exhaust), in (mm) ............... 1.4764 (37.500)
Camshaft Journal Bearing Clearance, in (mm) ............... 0.0016 (0.040) to 0.0031 (0.080)
Camshaft Bearing Journal Clearance, in (mm) ............... 0.0016 (0.040) to 0.0031 (0.080)
Camshaft Axial End Play, in (mm) ............... 0.0020 (0.050) to 0.0059 (0.150)
Rocker Arm Bushing to Shaft Clearance, in (mm) ............... 0.0006 (0.015) to 0.0022 (0.055)

Tightening Torques

Cylinder Head Short Bolt (Step 1) ............... 60 Nm (44.3 lb-ft)
Cylinder Head Long Bolt (Step 1) ............... 60 Nm (44.3 lb-ft)
Cylinder Head Short Bolt (Step 2) ............... 120 Nm (88.5 lb-ft)
Cylinder Head Long Bolt (Step 2) ............... 150 Nm (110.6 lb-ft)
Main Bearing Cap Fasteners (Step 1) ............... 50 Nm (36.9 lb-ft)
Main Bearing Cap Fasteners (Step 2) ............... 118 Nm (87.0 lb-ft)
Main Crankcase Block Right Side Bolt ............... 35 Nm (25.8 lb-ft)
Main Crankcase Block Left Side Bolt ............... 35 Nm (25.8 lb-ft)
Connecting Rod Cap Fasteners (Step 1) ............... 60 Nm (44.3 lb-ft)
Connecting Rod Cap Fasteners (Step 2) ............... 147 Nm (108.4 lb-ft)
Oil Cooling Nozzle Jet Fasteners ............... 24 Nm (17.7 lb-ft)
Gear Pump Attachment Bolts ............... 24 Nm (17.7 lb-ft)
Crankshaft Vibration Damper Pulley Center Bolt ............... 200 Nm (147.5 lb-ft)
Flywheel Assembly Bolts to Hub Core (Step 1) ............... 40 Nm (29.5 lb-ft)
Flywheel Assembly Bolts to Hub Core (Step 2) ............... 90 Nm (66.4 lb-ft)
Flywheel Bell Housing Outer Shell Mating Bolt ............... 55 Nm (40.6 lb-ft)
Camshaft Thrust Plate Axial Flange Bolts ............... 24 Nm (17.7 lb-ft)
Camshaft Timing Gear Central Drive Sprocket Bolt ............... 95 Nm (70.1 lb-ft)
Rocker Shaft Support Pillar Fasteners ............... 35 Nm (25.8 lb-ft)
Cylinder Head Upper Valve Rocker Cover Bolts ............... 11 Nm (8.1 lb-ft)
Crankcase Lower Pressed Steel Oil Pan Drain Plug ............... 45 Nm (33.2 lb-ft)
Crankcase Lower Pressed Steel Oil Pan Flange Bolts ............... 24 Nm (17.7 lb-ft)
High Pressure Fuel Common Rail Shell Mounting Bolts ............... 24 Nm (17.7 lb-ft)
High Pressure Fuel Injector Hold Down Clamp Bolt ............... 30 Nm (22.1 lb-ft)
High Pressure Fuel Injector Line Delivery Fitting Nuts ............... 27 Nm (19.9 lb-ft)
High Pressure Fuel Injection Pump Drive Gear Nut ............... 85 Nm (62.7 lb-ft)
Exhaust Gas Delivery Manifold Mounting Stud Nuts ............... 45 Nm (33.2 lb-ft)
Intake Charge Air Supply Manifold Bolts ............... 24 Nm (17.7 lb-ft)
Turbocharger Assembly Oil Drain Flange Bolts ............... 12 Nm (8.9 lb-ft)
Turbocharger Exhaust Gas Intake Mounting Stud Nuts ............... 45 Nm (33.2 lb-ft)
Water Pump Cooling Body Housing Mounting Fasteners ............... 24 Nm (17.7 lb-ft)
Coolant Thermostat Outlet Water Fitting ............... 24 Nm (17.7 lb-ft)
Starter Motor Mounting Flange Socket Bolts ............... 65 Nm (47.9 lb-ft)
Alternator Unit Rigid Pivot Bracket Support Bolt ............... 45 Nm (33.2 lb-ft)
Alternator Unit Adjusting Locking Bracket Bolt ............... 24 Nm (17.7 lb-ft)
Glow Plug Electrical Preheater Elements ............... 18 Nm (13.3 lb-ft)
Oil Pressure Sensor Switch ............... 15 Nm (11.1 lb-ft)
Coolant Fluid Temperature Sensor ............... 20 Nm (14.8 lb-ft)
Crankshaft Position Sensing Pickup Screw ............... 8 Nm (5.9 lb-ft)
Camshaft Position Speed Timing Sensor Screw ............... 8 Nm (5.9 lb-ft)
Crankcase Top Ventilation Breathing Mount Bolts ............... 11 Nm (8.1 lb-ft)

________________________________________________________________________________________

• Doosan Engines Specs
  
• Doosan D34 Specs
  
• Doosan DL06 Specs
  
• Doosan DL06K Specs
  
• Doosan DL08 Specs
  
• Doosan DL08K Specs
  

________________________________________________________________________________

________________________________________________________________________________________

_______________________________________________________________________________________

________________________________________________________________________________________

________________________________________________________________________________________

________________________________________________________________________________________

________________________________________________________________________________________

________________________________________________________________________________________

________________________________________________________________________________________

________________________________________________________________________________________