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Hatz 1B50 Engine

The Hatz 1B50 is a compact, air-cooled four-stroke single-cylinder diesel engine built by Motorenfabrik Hatz. Engineered with an upright cylinder configuration and a direct injection combustion system, this lightweight yet robust engine is designed for both mobile and stationary industrial applications. It features a high-strength die-cast light alloy crankcase, a light alloy cylinder head, a forged crankshaft, and a camshaft-driven valve timing mechanism. The 1B50 model complies with modern emissions standards, including EU Stage V certification for variable speed operations, and is highly regarded for its longevity and low fuel consumption in demanding environments.

The overhead valves are driven by a traditional camshaft valve timing assembly. In accordance with workshop service tolerances, the mechanical tappet clearance must be measured and set when the engine temperature is between 10C and 30C. Cylinder Bore: 93 mm. Piston Stroke: 76 mm. Total Displacement: 517 cc (31.5 cubic inches). The engine utilizes a high-pressure forced spray lubrication system driven by an integrated oil pump. Filtration: Lubricant passes through a main-flow fine filter mesh. Operating Pressure: 2.5 bar at an engine speed of 3,000 rpm, measured at a stabilized oil temperature of 100C.

Fuel System: The fuel architecture relies on an efficient direct injection combustion system. Fuel is fed from a standard 5.0-liter tank through an inline filtration system to an injection pump, delivering pressurized fuel directly into the single combustion chamber. The system supports multi-fuel compliance, allowing operation on standard automotive diesel fuel matching EN 590, BS 2869 A1/A2, ASTM D 975, as well as paraffinic synthetic diesels such as EN 15940 (HVO/XTL).

Cooling System: Thermal regulation is maintained via a forced-air cooling system. The combustion and cooling air is drawn into the engine housing through a dedicated intake opening. An internal fan or flywheel blower channels the airflow directly across the deep cooling fins machined into the alloy cylinder block and cylinder head, safely dissipating heat during operation.

General Technical Data

Engine Specifications

Engine Model ............... Hatz 1B50
Engine Type ............... 4-cycle single-cylinder direct injection air-cooled diesel
Number of Cylinders ............... 1
Cylinder Arrangement ............... Vertical or horizontal options
Engine Bore, in (mm) ............... 3.66 (93.0)
Engine Stroke, in (mm) ............... 2.99 (76.0)
Displacement, cu.in (L) ............... 31.5 (0.517)
Rated Engine Power, hp (kW) ............... 5.2-11.4 (3.9-8.5)
Rated Engine Speed, rpm ............... 1500-3600
Peak Torque ............... 27.4 Nm (20.2 lb-ft) at 2500 rpm
Idle Speed ............... 950-1050 rpm
Aspiration Type ............... Naturally Aspirated
Operating Speed ............... 3000-3600 rpm
Compression Ratio ............... 20.5:1
Rotation Direction ............... Counter-clockwise facing power take-off flywheel side
Combustion Principle ............... Direct injection multi-hole nozzle configuration design
Crankcase Breather ............... Closed loop positive internal ventilation check valve line
Cylinder Block Type ............... Die-cast aluminum light alloy crankcase
Cylinder Head Type ............... Light alloy cast
Lubrication System ............... Forced spray splash combination system
Oil Pump Type ............... Internal gear-driven pump
Oil Filter Type ............... Cleanable mesh screen style oil strainer element
Cooling System ............... Forced air axial cooling fan flywheel integrated blower unit
Air Cleaner Type ............... Dry-type dual-stage element cartridge unit
Emission Certification ............... EU Stage V US EPA Tier 4 final compliance standard
Starting System ............... Recoil manual rope pull starter or electric starter
Electrical System ............... 12V DC
Alternator Output ............... 10-16A

Fuel System

Injection Pump Type ............... Integrated high pressure single unit jerk injection block design
Injection Nozzle Type ............... Multi-hole micro orifice direct combustion chamber spray tip
Fuel Injection Pressure, psi (bar) ............... 2900-3625 (200-250)
Fuel Tank Capacity, gal (L) ............... 1.32 (5.0)
Fuel Filter Type ............... Inline paper element spin-on or tank integrated cartridge canister
Fuel Specification ............... EN 590 ASTM D975 Ultra Low Sulfur Diesel BS2869 A1 A2 profiles
Governor Type ............... Mechanical centrifugal flyweight governor linkage arrangement
Fuel Supply Line Size, in (mm) ............... 0.315 (8.0) internal hose inside dimension profile
Fuel Return Line System ............... External low pressure return bleed loop routing to tank cap inlet
Injection Timing Angle ............... 12-14 degrees before top dead center mark setting index location
Nozzle Opening Pressure, bar (psi) ............... 220-230 (3190-3335)

Dimensions and Weight

Overall Length, in (mm) ............... 13.7 (350)
Overall Width, in (mm) ............... 15.4 (390)
Overall Height, in (mm) ............... 18.9 (480)
Dry Weight (Recoil starter), lbs (kg) ............... 113 (51.2)
Dry Weight (Electric starter), lbs (kg) ............... 125 (56.5)

Maintenance Data

Service Information

Compression Pressure, Minimum, psi (bar) ............... 406 (28.0)
Minimum Oil Pressure at Idle, psi (bar) ............... 14.5 (1.0)
Nominal Oil Pressure at 3000 rpm, psi (bar) ............... 36.25 (2.5)
Maximum Exhaust Temperature, F (C) ............... 1112 (600)
Inlet Valve Clearance, Cold, in (mm) ............... 0.004 (0.10)
Exhaust Valve Clearance, Cold, in (mm) ............... 0.004 (0.10)

Engine Oil

Engine Oil Type .................. SAE 10W-40, SAE 10W-30, or 15W-40
API Service Classifications ......................... CF, CH-4, CK-4, CJ-4
Engine Oil Capacity (Maximum), L (US qt) ............... 1.5 (1.59)
Engine Oil Capacity (Minimum), L (US qt) ............... 1.0 (1.05)

Service Intervals

Change engine oil ............... Every 250 hours
Clean oil filter ............... Every 1000 hours
Clean air filter ............... Every 100 hours
Replace air filter ............... Every 500 hours
Replace fuel filter ............... Every 500 hours
Valve clearance adjustment ............... Every 250 hours
Fuel system inspection ............... Every 250 hours
Check battery ............... Every 250 hours
Inspect breather valve ............... Every 1000 hours

Service Specifications

Cylinder Bore Inside Diameter, in (mm) ............... 3.6614-3.6622 (93.000-93.022)
Cylinder Bore Max Wear Limit, in (mm) ............... 3.6653 (93.100)
Connecting Rod Small End Bushing I.D, in (mm) ............... 1.1031-1.1039 (28.020-28.040)
Connecting Rod Big End Bore I.D, in (mm) ............... 1.9685-1.9693 (50.000-50.020)
Crankshaft Main Journal Outer Diameter, in (mm) ............... 1.9675-1.9681 (49.975-49.990)
Crankpin Journal Outer Diameter, in (mm) ............... 1.7706-1.7712 (44.975-44.990)
Crankshaft Axial End Play, in (mm) ............... 0.0039-0.0118 (0.100-0.300)
Connecting Rod Side Clearance, in (mm) ............... 0.004-0.012 (0.10-0.30)
Piston Skirt Outer Diameter, in (mm) ............... 3.6574-3.6582 (92.900-92.920)
Piston to Cylinder Wall Clearance, in (mm) ............... 0.0031-0.0047 (0.080-0.120)
Piston Pin Bore Inside Diameter, in (mm) ............... 1.1024-1.1027 (28.000-28.008)
Piston Pin Outer Diameter, in (mm) ............... 1.1021-1.1023 (27.992-28.000)
First 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) ............... 0.1181-0.1189 (3.000-3.020)
First 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) ............... 0.0098-0.0157 (0.250-0.400)
First Ring Groove Side Clearance, in (mm) ............... 0.0023-0.0035 (0.060-0.090)
Second Ring Groove Side Clearance, in (mm) ............... 0.0015-0.0029 (0.040-0.075)
Oil Ring Groove Side Clearance, in (mm) ............... 0.0011-0.0025 (0.030-0.065
Cylinder Head Surface Distortion Limit, in (mm) ............... 0.0019 (0.050)
Intake Valve Head Diameter, in (mm) ............... 1.338 (34.0)
Exhaust Valve Head Diameter, in (mm) ............... 1.141 (29.0)
Intake Valve Stem Diameter, in (mm) ............... 0.2740-0.2748 (6.960-6.980)
Exhaust Valve Stem Diameter, in (mm) ............... 0.2732-0.2740 (6.940-6.960)
Valve Guide Inside Diameter, in (mm) ............... 0.2756-0.2764 (7.000-7.020)
Intake Valve Stem to Guide Clearance, in (mm) ............... 0.0008-0.0023 (0.020-0.060)
Exhaust Valve Stem to Guide Clearance, in (mm) ............... 0.0015-0.0031 (0.040-0.080)
Intake Valve Seat Width, in (mm) ............... 0.039-0.055 (1.00-1.40)
Exhaust Valve Seat Width, in (mm) ............... 0.055-0.070 (1.40-1.80)
Valve Spring Free Length, in (mm) ............... 1.653 (42.0)
Camshaft Journal Diameter, in (mm) ............... 0.9832-0.9838 (24.975-24.990)
Camshaft Journal Bearing Clearance, in (mm) ............... 0.0011-0.0029 (0.030-0.075)
Intake Cam Lobe Height, in (mm) ............... 1.259 (32.0)
Exhaust Cam Lobe Height, in (mm) ............... 1.259 (32.0)

Tightening Torques

Cylinder Head Nut, lb-ft (Nm) ............... 7.3 (10.0)
Connecting Rod Cap Bolt, lb-ft (Nm) ............... 29.5-31.0 (40.0-42.0)
Flywheel Retention Main Center Bolt, lb-ft (Nm) ............... 59.0-62.6 (80.0-85.0)
Crankcase Cover Perimeter Bolts, lb-ft (Nm) ............... 16.2-18.4 (22.0-25.0)
Oil Drain Screw Plug Hex Base, lb-ft (Nm) ............... 36.8 (50.0)
Rocker Arm Shaft Retaining Nut, lb-ft (Nm) ............... 14.7 (20.0)
Fuel Injector Hold Down Clamp Screw, lb-ft (Nm) ............... 11.0 (15.0)
Injection Pump Delivery Valve Holder, lb-ft (Nm) ............... 29.5 (40.0)
Main Bearing Housing Anchor Flange, lb-ft (Nm) ............... 18.4 (25.0)
Governor Weight Assembly Screw, lb-ft (Nm) ............... 7.3 (10.0)
Recoil Starter Housing Mount Screws, lb-ft (Nm) ............... 7.3 (10.0)
Exhaust Silencer Muffler Mount Nuts, lb-ft (Nm) ............... 16.2 (22.0)
Air Cleaner Filter Housing Base Nut, lb-ft (Nm) ............... 6.6 (9.0)
Valve Cover Retaining Center Nut, lb-ft (Nm) ............... 8.8 (12.0)
Alternator Stator Ring Support Screws, lb-ft (Nm) ............... 4.4 (6.0)
Starter Motor Flange Mounting Bolts, lb-ft (Nm) ............... 29.5 (40.0)
Oil Pressure Switch Sensor, lb-ft (Nm) ............... 14.7 (20.0)
Fuel Tank Base Mounting Bracket Hardware, lb-ft (Nm) ............... 16.2 (22.0)
Speed Control Lever Friction Adjustment Nut, lb-ft (Nm) ............... 3.6 (5.0)
Breather Valve Cover Plate Screws, lb-ft (Nm) ............... 2.9 (4.0)
Flywheel Shroud Cowling Metal Fasteners, lb-ft (Nm) ............... 7.3 (10.0)
Oil Pump Assembly Face Bolts, lb-ft (Nm) ............... 8.8 (12.0)
Crankshaft Timing Gear Fastener, lb-ft (Nm) ............... 44.2 (60.0)
Camshaft Thrust Washers Bolt, lb-ft (Nm) ............... 8.8 (12.0)
Injection Fuel Pipe High Pressure Nut, lb-ft (Nm) ............... 18.4 (25.0)
Fuel Return Hose Clamp Interface Screw, lb-ft (Nm) ............... 1.4 (2.0)
Automatic Decompression Mechanism Nut, lb-ft (Nm) ............... 11.0 (15.0)

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• Hatz Engines Specs
  
• Hatz 1B20 Specs
  
• Hatz 1B20-6 Specs
  
• Hatz 1B30 Specs
  
• Hatz 1B30E Specs
  
• Hatz 1B40 Specs
  
• Hatz 1B50E Specs
  

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