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Hatz 1D42 Engine

The Hatz 1D42 is an air-cooled, single-cylinder, four-stroke industrial diesel engine developed by Motorenfabrik Hatz, engineered for heavy-duty applications like construction machinery, generators, and pumps. Characterized by its robust cast-iron vertical cylinder design and lightweight aluminum cylinder head, this power unit emphasizes mechanical reliability, modular configurations (such as the sound-insulated Silent Pack), and compliance with strict global emission standards like EU Stage V and US EPA Tier 4f.

The Hatz 1D42 stands out for its high power-to-weight ratio and versatile layout options, enabling up to four power-take-off points. It utilizes an efficient direct-injection combustion strategy to minimize thermal losses and maximize fuel economy. Built to operate under rugged industrial conditions, the engine supports mechanical or electric starting options and can safely operate at up to a 30-degree continuous angle of inclination.

The valvetrain features a mechanical valve control arrangement. Overhead valves are actuated via a camshaft housed inside the crankcase through pushrods and rocker arms. Periodic maintenance requires manual inspection and adjustment of tappet clearance every 250 operating hours to maintain correct timing and sealing performance. Bore: 90 mm. Stroke: 70 mm. Total Displacement: 0.445 liters (445 cc). Compression Ratio: 20.0:1 to 22.0:1.

The direct-fuel injection system is comprised of a dedicated fuel tank, mechanical feed pumps, rigid high-pressure lines, an inline fuel filter with a water separator, and a high-pressure mechanical fuel injector assembly. Fuel delivery is synchronized directly with the compression stroke. The system requires ultra-low sulfur diesel complying with standard specifications like EN 590, BS 2869, or ASTM D 975. Fuel cartridges must be replaced every 500 operating hours to protect the close-tolerance injection equipment from accelerated wear.

The engine employs a pressurized lubrication system fed by an internal oil pump from the oil sump. It features replaceable full-flow oil filters or mesh strainers to catch particulate contamination. Regular level checks are completed using the integrated dipstick, with standard oil and filter replacement scheduled at 250-hour operational intervals. Cooling is achieved entirely via an integrated air-cooling setup. An engine-driven fan forces atmospheric air across the deep cooling fins cast directly into the iron cylinder block and aluminum cylinder head.

General Technical Data

Engine Specifications

Engine Model ............... Hatz 1D42
Engine Type ............... 4-stroke single-cylinder air-cooled direct injection diesel engine
Number of Cylinders ............... 1
Engine Bore, in (mm) ............... 3.54 (90.0)
Engine Stroke, in (mm) ............... 2.76 (70.0)
Displacement, cu.in (L) ............... 27.2 (0.445)
Rated Power, hp (kW) ............... 4.4-9.4 (3.3-7.0)
Maximum Power at 3600 rpm, hp (kW) ............... 9.4 (7.0)
Minimum Power at 1500 rpm, hp (kW) ............... 4.4 (3.3)
Rated Engine Speed, rpm ............... 1500-3600
Peak Torque, lb-ft (Nm) ............... 16.6 (22.5) at 2000-2500 rpm
Low Idle Speed, rpm ............... 800-850
Aspiration Type ............... Naturally Aspirated
Compression Ratio ............... 21.5:1
Sense of Rotation from Flywheel View ............... Counter-clockwise / Left
Combustion System ............... Direct injection with multi-hole nozzle
Crankcase Material ............... Die-cast light alloy
Cylinder Material ............... Gray cast iron
Cylinder Head Material ............... Light alloy
Cooling System ............... Forced air cooling via flywheel fan
Lubrication System ............... Full-pressure lubrication with gear pump
Oil Pump Type ............... Gear type forced lubrication delivery pump
Oil Filter Type ............... Full-flow with spin-on canister filter
Air Cleaner Type ............... Dry element
Crankcase Breather Integration ............... Internal routed to the intake port
Decompression Mechanism ............... Automatic mechanical decompression
Power Take-Off Points ............... Up to 3 independent take-off configurations
Emissions Compliance Rating ............... EU Stage V and US EPA Tier 4 Final
Starting System ............... Hand crank mechanism or electric starter
Electrical System ............... 12V or 24V

Fuel System

Injection Pump Type ............... Hatz high-pressure single-plunger injection pump unit
Injection Nozzle Type ............... Multi-hole direct injection nozzle tip unit
Fuel Injection Pressure, psi (bar) ............... 3625-3916 (250-270)
Fuel Delivery Feed Pump ............... Mechanical diaphragm type pump driven by engine camshaft
Fuel Filter System ............... High efficiency spin-on element with water separation trap
Recommended Fuel Grade ............... EN 590, BS 2869 A1/A2, ASTM D 975-09a diesel
Fuel Tank Capacity, gal (L) ............... 1.32 (5.0)
Fuel Consumption Rate, lb/hp-hr (g/kW-h) ............... 0.395 (240)
Governing System ............... Mechanical centrifugal governor with speed control lever
Injection Advance Timing, deg BTDC ............... 11-13
Fuel Return Pipeline Connection ............... Low-pressure rubber overflow circuit hose assembly
Injection Nozzle Opening Hold Pressure, bar ............... 250 plus 8 tolerance value limit
Fuel System Venting Mechanism ............... Mechanical manual bleed screw on pump deck flange
Maximum Fuel Lift Suction Height, ft (m) ............... 3.3 (1.0)
Maximum Fuel Return Temperature, F (C) ............... 140 (60)
Nozzle Needle Lift Travel, in (mm) ............... 0.0078 (0.20)
Plunger Diameter, in (mm) ............... 0.275 (7.0)
Injection Pipe Internal Diameter, in (mm) ............... 0.078 (2.0)
Injection Pipe Outer Diameter, in (mm) ............... 0.236 (6.0)

Dimensions and Weight

Overall Engine Length, in (mm) ............... 17.0 (430)
Overall Engine Width, in (mm) ............... 19.7 (500)
Overall Engine Height, in (mm) ............... 23.0 (585)
Dry Weight with Handle Start, lbs (kg) ............... 157 (71)
Dry Weight with Electric Starter, lbs (kg) ............... 172 (78)

Maintenance Data

Service Information

Oil Pressure at Low Idle, psi (bar) ............... 8.7 (0.6)
Oil Pressure at Max Speed, psi (bar) ............... 29.0 (2.0)
Maximum Crankcase Oil Temperature, F (C) ............... 248 (120)
Intake Valve Clearance (Cold), in (mm) ............... 0.0039 (0.10)
Exhaust Valve Clearance (Cold), in (mm) ............... 0.0078 (0.20)

Engine Oil

Engine Oil Type .................. SAE 5W-30, SAE 10W-30, or 15W-40
API Service Classifications ......................... CF, CH-4, or CJ-4
Engine Oil Capacity, Maximum Level, US qt (L) ............... 1.27 (1.2)
Engine Oil Capacity, Minimum Level, US qt (L) ............... 0.85 (0.8)

Service Intervals

Change engine oil ............... Every 250 hours
Replace oil filter ............... Every 250 hours
Replace air filter ............... Every 500 hours
Replace fuel filter ............... Every 500 hours
Valve clearance adjustment ............... Every 250 hours
Fuel system inspection ............... Every 500 hours
Clean cooling fin ............... Every 250 hours
Check battery ............... Every 250 hours
Inspect crankcase valve ............... Every 1000 hours

Service Specifications

Cylinder Bore Inner Diameter, in (mm) ............... 3.5433-3.5441 (90.000-90.022)
Cylinder Bore Maximum Out of Round, in (mm) ............... 0.0039 (0.10)
Crankshaft Main Journal Diameter, in (mm) ............... 1.9685-1.9691 (50.000-50.016)
Crankpin Journal Diameter, in (mm) ............... 1.7716-1.7722 (45.000-45.016)
Connecting Rod Big End Clearance, in (mm) ............... 0.0011-0.0031 (0.030-0.080)
Connecting Rod Small End Bushing I.D, in (mm) ............... 0.9842-0.9848 (25.000-25.013)
Crankshaft Axial End Play, in (mm) ............... 0.0039-0.0118 (0.100-0.300)
Piston to Cylinder Wall Clearance, in (mm) ............... 0.0015-0.0027 (0.040-0.070)
Piston Pin Outer Diameter, in (mm) ............... 0.9838-0.9842 (24.990-25.000)
Piston Pin to Small End Bushing Clearance, in (mm) ............... 0.0001-0.0009 (0.003-0.023)
Top Ring Groove Width, in (mm) ............... 0.0787-0.0795 (2.000-2.020)
Second Ring Groove Width, in (mm) ............... 0.0787-0.0795 (2.000-2.020)
Oil Ring Groove Width, in (mm) ............... 0.1574-0.1582 (4.000-4.020)
Top Ring End Gap, in (mm) ............... 0.0098-0.0157 (0.250-0.400)
Second Ring End Gap, in (mm) ............... 0.0098-0.0157 (0.250-0.400)
Oil Ring End Gap, in (mm) ............... 0.0098-0.0177 (0.250-0.450)
Intake Valve Stem Outer Diameter, in (mm) ............... 0.2755-0.2761 (7.000-7.015)
Exhaust Valve Stem Outer Diameter, in (mm) ............... 0.2748-0.2754 (6.980-6.995)
Intake Valve Guide Inner Diameter, in (mm) ............... 0.2771-0.2783 (7.040-7.070)
Exhaust Valve Guide Inner Diameter, in (mm) ............... 0.2771-0.2783 (7.040-7.070)
Intake Valve Stem to Guide Clearance, in (mm) ............... 0.0059 (0.15)
Exhaust Valve Stem to Guide Clearance, in (mm) ............... 0.0059 (0.15)
Valve Head Recess Depth New, in (mm) ............... 0.0275-0.0433 (0.700-1.100)
Camshaft Journal Outer Diameter, in (mm) ............... 1.1811-1.1818 (30.000-30.020)
Camshaft Bearing Clearance, in (mm) ............... 0.0015-0.0035 (0.040-0.090)
Camshaft Lobe Height (Intake), in (mm) ............... 1.3385 (34.00)
Camshaft Lobe Height (Exhaust), in (mm) ............... 1.3385 (34.00)
Rocker Arm Bushing Inner Diameter, in (mm) ............... 0.5511-0.5519 (14.000-14.018)
Rocker Arm Shaft Outer Diameter, in (mm) ............... 0.5499-0.5505 (13.968-13.984)

Tightening Torques

Cylinder Head Stud Nuts (1-Stage), lb-ft (Nm) ............... 14.7 (20.0)
Cylinder Head Stud Nuts (2-Stage), lb-ft (Nm) ............... 29.5 (40.0)
Cylinder Head Stud Nuts (3-Stage), lb-ft (Nm) ............... 36.8-39.8 (50.0-54.0)
Connecting Rod Big End Cap Bolts, lb-ft (Nm) ............... 25.8-28.0 (35.0-38.0)
Flywheel Retaining Central Nut, lb-ft (Nm) ............... 258.1-272.8 (350.0-370.0)
Main Bearing Flange Housing Screws, lb-ft (Nm) ............... 18.4-20.6 (25.0-28.0)
Crankcase Sump Pan Drain Plug, lb-ft (Nm) ............... 36.8 (50.0)
Oil Pump Assembly Retention Torx Fasteners, lb-ft (Nm) ............... 6.6-8.1 (9.0-11.0)
Injection Pump Retaining Flange Nuts, lb-ft (Nm) ............... 18.4 (25.0)
Injection Nozzle Hold-Down Clamping Bracket Nut, lb-ft (Nm) ............... 22.1 (30.0)
High Pressure Fuel Delivery Pipe Union Caps, lb-ft (Nm) ............... 18.4-22.1 (25.0-30.0)
Camshaft Thrust Washer Retention Screws, lb-ft (Nm) ............... 7.3 (10.0)
Crankcase Breathing Cover Plate Small Screws, lb-ft (Nm) ............... 6.6 (9.0)
Rocker Arm Support Shaft Clamping Flange Nut, lb-ft (Nm) ............... 29.5 (40.0)
Valve Cover Cap Central Acorn Nut, lb-ft (Nm) ............... 7.3-8.8 (10.0-12.0)
Timing Gear Cover Case Perimeter Screws, lb-ft (Nm) ............... 16.9-19.1 (23.0-26.0)
Speed Control Lever Assembly Bracket, lb-ft (Nm) ............... 18.4 (25.0)
Flywheel Fan Plastic Elements Bolts, lb-ft (Nm) ............... 7.3 (10.0)
Alternator Stator Core Frame Screws, lb-ft (Nm) ............... 6.6 (9.0)
Electric Starter Shell Mounting Flange Bolts, lb-ft (Nm) ............... 29.5-33.1 (40.0-45.0)
Exhaust Manifold Stud Nuts Head, lb-ft (Nm) ............... 18.4-20.6 (25.0-28.0)
Air Filter Box Shell Backplate Mounting Nuts, lb-ft (Nm) ............... 7.3-8.8 (10.0-12.0)
Fuel Tank Shell Support Bracket Fasteners, lb-ft (Nm) ............... 18.4 (25.0)
Oil Pressure Monitoring Warning Switch, lb-ft (Nm) ............... 14.7 (20.0)
Glow Plug Preheater Element, lb-ft (Nm) ............... 14.7-18.4 (20.0-25.0)
Decompression Shaft Dynamic Set Screw, lb-ft (Nm) ............... 5.1-6.6 (7.0-9.0)
Governor Flyweight Support Carrier Pin, lb-ft (Nm) ............... 16.9 (23.0)
Fuel Feed Diaphragm Lift Pump Housing Bolts, lb-ft (Nm) ............... 7.3 (10.0)
Speed Control Bowden Cable Clamp Screw, lb-ft (Nm) ............... 4.4 (6.0)
Crankcase Engine Mount Isolation Foot Bolt, lb-ft (Nm) ............... 55.3-62.6 (75.0-85.0)

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• Hatz Engines Specs
  
• Hatz 1D41 Specs
  
• Hatz 1D41S Specs
  
• Hatz 1D42S Specs
  
• Hatz 1D50 Specs
  
• Hatz 1D50S Specs
  
• Hatz 1D50Z Specs
  

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