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Hatz 1D42S Engine

The Hatz 1D42S is an air-cooled, single-cylinder, four-stroke industrial diesel engine built by Motorenfabrik Hatz. Designed as part of the Hatz D-series (specifically the standard "S" non-encapsulated configuration), it is highly engineered for heavy-duty applications in construction machinery, generators, and pumps. Structurally, it features a rugged vertical grey cast iron cylinder, a die-cast light alloy crankcase, and a light alloy cylinder head. Plain slide bearings support the crankshaft and big end journal. To ensure smooth performance for a single-cylinder layout, the engine incorporates compensation weights on the flywheel-side crank arm alongside integrated balance weights cast directly into the flywheel.

The overhead valve mechanism uses a mechanical control layout. Valve actuation is managed by a gear-driven camshaft via tappets, push-rods, and rocker arms housed inside the light alloy cylinder head. Rated Output Range: 3.3-7.0 kW (4.5-9.5 hp) depending on the factory governor calibration and target RPM configuration. Bore Diameter: 90 mm. Stroke Length: 70 mm. Total Displacement: 445 cc (0.445 liters).

Fuel delivery utilizes a direct-injection design optimized for high thermal efficiency and low structural emissions. The supply chain features a mechanical fuel feed pump supplying a dedicated high-pressure injection pump. This pump feeds a multi-hole injection nozzle via a rigid fuel pressure pipe. System venting is handled by an automated bleeding cycle (primarily configuration-dependent where fuel tanks are mounted above the injection pump plane) supplemented by an integrated injection pump bleeder valve. An automated extra fuel device handles starting enrichment cycles.

Lubrication is managed via a forced pressure lubrication loop driven by an internal gear-type oil pump. A main-flow oil filter elements protects downstream components. Operating Pressure: Minimum allowable oil pressure is 0.6 bar when the engine is idling at 850 rpm. The engine relies on a direct, forced-air cooling setup. An integrated flywheel fan forces high-volume airflow through localized air cowling sheets directly across the cooling fins of the cast-iron block and alloy cylinder head. Because the charging alternator and cooling fan are entirely integrated into the flywheel assembly, the system functions natively without requiring external V-belts or auxiliary drive pulleys.

General Technical Data

Engine Specifications

Engine Model ............... Hatz 1D42S
Engine Type ............... 4-stroke air-cooled single-cylinder vertical direct injection diesel
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 Engine Power, hp (kW) ............... 4.5-9.5 (3.3-7.0)
Rated Engine Speed, rpm ............... 1500-3600
Peak Torque ............... 22.5 Nm (16.6 lb-ft) at 2200-2600 rpm
Idle Speed ............... 850-950 rpm
Aspiration Type ............... Naturally Aspirated
Operating Speed ............... 3000-3600 rpm
Compression Ratio ............... 21.5:1
Firing Order ............... 1-1
Rotation Direction ............... Counterclockwise looking at power take-off flywheel side
Crankcase Material ............... High-strength die-cast aluminum alloy
Cylinder Liner Material ............... Highly wear-resistant gray cast iron
Connecting Rod Bearings ............... Multi-layer plain precision slide bearings
Valve Train Operation ............... Camshaft, pushrods, tappets, and rocker arms
Exhaust System ............... Integrated heavy-duty industrial acoustic silencer
Cylinder Block Type ............... Die-cast light alloy crankcase with cast iron cylinder barrel
Cylinder Head Type ............... Die-cast light alloy
Lubrication System ............... Forced feed circulation pressure system
Oil Pump Type ............... Gear-driven force pump
Oil Filter Type ............... Main-flow fine mesh filter cartridge, spin-on optional
Cooling System ............... Forced air cooling via flywheel blower fan fan
Air Cleaner Type ............... Dry type paper element with integrated cyclone pre-cleaner
Starting System ............... Electric starter motor with optional recoil or crankhandle backup
Electrical System ............... 12V or 24V
Alternator Capacity ............... 14A or 7A

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 Length, in (mm) ............... 17.0 (430)
Overall Width, in (mm) ............... 18.6 (470)
Overall Height, in (mm) ............... 19.7 (500)
Dry Weight, 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, Max, gal (L) ............... 0.317 (1.20)
Engine Oil Capacity, Min, gal (L) ............... 0.211 (0.80)

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 breather 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 1D42 Specs
  
• Hatz 1D50 Specs
  
• Hatz 1D50S Specs
  
• Hatz 1D50Z Specs
  

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