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Hatz 1B50E Engine

The Hatz 1B50E is a single-cylinder, air-cooled, four-stroke industrial diesel engine belonging to the compact Hatz B-Series. It features a lightweight construction with a die-cast light alloy crankcase and cylinder head, making it ideal for mobile and stationary applications where spatial and weight constraints are tight. The "E" designation marks the inclusion of an electronic governor, which provides precise speed control, less mechanical wear, and integration capabilities with engine management and diagnostic fleet platforms. It is certified compliant with strict modern emission standards, including EPA Tier 4 Final and EU Stage V.

The valvetrain uses an overhead valve (OHV) layout. Timing mechanisms are driven via a camshaft, operating through a finger follower, pushrods, and rocker arms to actuate the intake and exhaust valves. Cylinder Bore: 93 mm (3.66 inches). Piston Stroke: 76 mm (2.99 inches). Total Displacement: 0.517 liters (517 cc / 31.55 cubic inches). Compression Ratio: 20.5:1.

Fuel System: Combustion is handled using a highly efficient direct injection method. The fuel system incorporates an electronic governor module paired with a mechanical injection pump and delivery lines. Fuel filtering consists of a line-integrated cartridge designed to prevent micro-particles from entering the injection nozzles. The system supports standard industrial diesel formulations including EN 590, ASTM D 975, BS 2869 A1/A2, and synthetic paraffinic options like HVO/XTL (EN 15940).

Lubrication is managed via a pressurized system. Oil distribution is handled under constant pressure through the main oil channels, passing through a main-flow fine filter to capture sediment and debris before treating key friction surfaces like the forged crankshaft. The engine uses an open-loop, direct air-cooling layout. Forced air is ducted across the deeply finned surfaces of the light alloy cylinder head and the alloy engine block via an integrated flywheel blower fan to safely dissipate operational heat during continuous high-load intervals.

General Technical Data

Engine Specifications

Engine Model ............... Hatz 1B50E
Engine Type ............... 4-stroke single-cylinder air-cooled direct-injection diesel
Number of Cylinders ............... 1
Cylinder Arrangement ............... Upright vertical
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) ............... 5.2-10.6 (3.9-7.9)
Rated Engine Speed, rpm ............... 1500-3600
Peak Torque ............... 18.9 lb-ft (25.6 Nm) at 2500 rpm
Idle Speed ............... 1000-1200 rpm
Aspiration Type ............... Naturally Aspirated
Operating Speed ............... 3600 rpm
Compression Ratio ............... 20.5:1
PTO Shaft Rotation ............... Counterclockwise looking at PTO side
Combustion System ............... Direct injection with electronic fuel control
Valve Arrangement ............... Overhead valve pushrod operated
Valves Per Cylinder ............... 2
Crankshaft Design ............... Forged steel counterweighted single throw
Crankcase Breather System ............... Closed circuit diaphragm ventilation
Decompression Mechanism ............... Automatic mechanical compression release
Camshaft Drive Method ............... Direct gear mesh train from crankshaft
Cylinder Block Type ............... Die-cast light alloy crankcase
Cylinder Head Type ............... Light alloy aluminum
Lubrication System ............... Pressurized forced spray
Oil Pump Type ............... Gear-driven trochoid
Oil Filter Type ............... Main flow fine mesh metal screen filter
Cooling System ............... Forced-air cooled via flywheel fan blower
Air Cleaner Type ............... Dry paper cartridge with integrated pre-cleaner
Exhaust Emission Certification ............... EPA Tier IV final and EU Stage V
Starting System ............... Electric Starter
Electrical System ............... 12V or 24V
Alternator Output ............... 10-18A

Fuel System

Injection Method ............... Direct injection mechanical electronic controlled
Fuel Injection Pump Type ............... High pressure single plunger element pump
Injection Pump Drive ............... Camshaft lobe operated mechanical tappet
Fuel Injector Nozzle Type ............... Multi-hole micro orifice nozzle tip
Injection Pressure, psi (bar) ............... 2900-3625 (200-250)
Fuel Delivery Control ............... Solenoid valve electronic governor interface
Fuel Filter Element ............... Spin-on fine paper sedimenter cartridge
Fuel Transfer Pump ............... Electronic low pressure lift pump 12V DC
Fuel Tank Capacity, gal (L) ............... 1.32 (5.0)
Fuel Specification Standard ............... EN 590, ASTM D 975 1D/2D, BS 2869 A1/A2
Governor Type ............... Mechanical centrifugal spring-loaded governor
Max Fuel Return Temperature, deg F (deg C) ............... 140 (60)
Fuel System Prime Procedure ............... Automatic self priming electric fuel feed
Injection Line High Pressure Tubing, in (mm) ............... 0.236 (6.0) outer diameter steel
Nozzle Opening Pressure Standard, psi (bar) ............... 3190 (220)
Water Separator Filter Type ............... Transparent water bowl trap mesh insert
Injection Pump Plunger Diameter, in (mm) ............... 0.275 (7.0)
Injection Pump Plunger Stroke, in (mm) ............... 0.236 (6.0)
Fuel System Air Bleed Point Screw ............... Top face bleed bolt element block

Dimensions and Weight

Overall Length, in (mm) ............... 14.4 (365)
Overall Width, in (mm) ............... 16.2 (410)
Overall Height, in (mm) ............... 18.9 (480)
Dry Weight, 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
Lube Oil Capacity (Max), US qt (L) ............... 1.59 (1.5)
Lube Oil Capacity (Min), US qt (L) ............... 0.84 (0.8)

Service Intervals

Change engine oil ............... Every 250 hours
Clean oil filter ............... Every 1000 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 100 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)
Valve Clearance Adjusting Tappet Jam Nuts, lb-ft (Nm) ............... 8.1 (11.0)
Crankcase Breather Separator Tube Screws, lb-ft (Nm) ............... 4.4 (6.0)
Timing Case Front Enclosure Cover Screws, lb-ft (Nm) ............... 17.7 (24.0)
Electric Starter Solenoid Terminal Power Post, lb-ft (Nm) ............... 5.9 (8.0)

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• Hatz Engines Specs
  
• Hatz 1B20 Specs
  
• Hatz 1B20-6 Specs
  
• Hatz 1B30 Specs
  
• Hatz 1B30E Specs
  
• Hatz 1B40 Specs
  
• Hatz 1B50 Specs
  

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