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Wisconsin AENLD Engine

The Wisconsin AENLD is a heavy-duty, single-cylinder, four-stroke internal combustion engine engineered by the Wisconsin Motor Corporation
for demanding agricultural and industrial environments. Built around a rugged, heavy-duty cast-iron block and cylinder structure, this power unit is designed for continuous, high-torque operation. The "D" suffix in the model designation indicates a specific "Long Life" valve train upgrade. Unlike the base AENL model, the AENLD incorporates a highly durable stellite exhaust valve, a matching stellite valve seat insert, and a mechanical valve rotator. These severe-duty components resist thermal warping and carbon buildup, significantly extending the time between valve maintenance intervals during continuous industrial operations.

Valve Configuration: L-head (side-valve) configuration driven by an internal camshaft. Intake Valve: Heat-resistant alloy steel valve paired with a standard guide. Exhaust Valve: Premium stellite-faced valve interacting with a hardened stellite valve seat insert. Valvetrain Enhancements: Integrated mechanical valve rotator mechanism on the exhaust assembly to promote uniform heat distribution and reduce uneven wear. Cylinder Bore: 3.00 inches (76.2 mm). Piston Stroke: 3.25 inches (82.55 mm). Total Displacement: 23 cubic inches (377 cc). Compression Pressure: 85 to 95 psi measured at cranking speed.

Fuel System Carburetor Assembly: Updraft style carburetor, typically utilizing a Zenith (Division of Bendix Aviation Corporation) Model 68-7 carburetor. Fuel Delivery: Fuel is supplied via gravity feed from a 1.7-gallon fuel tank or pressurized by a mechanical fuel pump manufactured by companies like the Blackstone Manufacturing Company. Adjustments: Features a factory-preset or adjustable high-speed main jet needle alongside an adjustable low-speed idle air-bleed screw to tune air-to-fuel ratios. Fuel Specification: Designed to operate on clean, regular unleaded gasoline with a minimum rating of 87 octane. To protect vintage fuel system seals, ethanol content must be kept under 10%.

Lubrication Type: Internal splash lubrication system. Delivery: Driven by an internal mechanical oil pump assembly and an oil spray nozzle mechanism to distribute oil continuously over the crankshaft throw, connecting rod, and camshaft assembly. Cooling Type: Forced-air cooling system. Mechanism: A flywheel-mounted blower fan pushes high-velocity ambient air directly through a system of formed sheet-metal air shrouding. Heat Dissipation: Air currents are routed directly across the external cooling fins cast into the cylinder head and engine block, eliminating the need for a radiator, water pump, or liquid coolant.

General Technical Data

Engine Specifications

Engine Model ............... Wisconsin AENLD
Engine Type ............... 4-cycle single-cylinder L-head air-cooled heavy-duty gasoline
Number of Cylinders ............... 1
Cylinder Arrangement ............... Vertical single-cylinder
Engine Bore, in (mm) ............... 3.00 (76.2)
Engine Stroke, in (mm) ............... 3.25 (82.6)
Displacement, cu.in (L) ............... 23.0 (0.38)
Rated Engine Power, hp (kW) ............... 4.7-9.2 (3.5-6.9)
Rated Engine Speed, rpm ............... 1600-3600
Peak Torque ............... 15.3 lb-ft (20.7 Nm) at 2200 rpm
Idle Speed ............... 1000-1200 rpm
Aspiration Type ............... Naturally Aspirated
Operating Speed ............... 2400-3600 rpm
Compression Ratio ............... 5.1:1-5.5:1
Cylinder Block Type ............... Cast iron integrated crankcase and cylinder
Cylinder Head Type ............... Cast iron removable L-head with deep cooling fins
Lubrication System ............... Combination splash and pump full-pressure distribution
Oil Pump Type ............... Camshaft-driven plunger type pump with check balls
Oil Filter Type ............... External spin-on or bypass cartridge element optional
Cooling System ............... Air-cooled via flywheel blower shroud network
Air Cleaner Type ............... Heavy-duty oil bath or polyurethane element dry type
Starting System ............... Manual rope start or optional 12V electric starter motor
Electrical System ............... 12V electric or standalone magneto ignition circuit

Fuel System

Carburetor Manufacturer ............... Marvel-Schebler or Zenith
Carburetor Model Series ............... Marvel-Schebler TSX or Zenith 61/68 series
Carburetor Type ............... Updraft internal venturi variable jet configuration
Fuel Delivery Method ............... Gravity feed from upper tank or mechanical fuel pump
Mechanical Fuel Pump Drive ............... Camshaft lobe actuated rocker arm assembly
Fuel Tank Capacity, gal (L) ............... 1.50 (5.68)
Recommended Fuel Grade ............... Regular unleaded gasoline 86 octane minimum
Alternative Fuel Capability ............... Liquefied petroleum gas or natural gas conversion systems
Governor Type ............... Mechanical flyweight centrifugal type running in oil bath
Main Jet Adjustment ............... 1.25-1.50 turns open from needle seat position
Idle Jet Adjustment ............... 0.75-1.00 turns open from needle seat position
Choke Control Mechanism ............... Manual cable operational butterfly valve assembly
Fuel Strainer Configuration ............... Sediment bowl assembly with micro-fine screen filter
Maximum Fuel Pump Pressure, psi (kPa) ............... 2.0-3.5 (13.8-24.1)
Fuel Line Connection Diameter, in (mm) ............... 0.25 (6.35)
Float Setting Level, in (mm) ............... 0.28 (7.14)

Dimensions and Weight

Overall Length, in (mm) ............... 18.2 (465)
Overall Width, in (mm) ............... 19.5 (495)
Overall Height, in (mm) ............... 21.8 (555)
Dry Weight, lbs (kg) ............... 110 (50)
Shipping Weight, lbs (kg) ............... 130 (59)

Maintenance Data

Service Information

Spark Plug Gap, in (mm) ............... 0.030 (0.76)
Breaker Point Gap, in (mm) ............... 0.015 (0.38)
Distributor Point Gap, in (mm) ............... 0.020 (0.51)
Ignition Timing Position ............... 27.0 degrees BTDC
Intake Valve Clearance, Cold, in (mm) ............... 0.008 (0.20)
Exhaust Valve Clearance, Cold, in (mm) ............... 0.016 (0.41)

Engine Oil

Engine Oil Type .................. SAE 30, SAE 20W, or SAE 10W
API Service Classifications ......................... SE, SF, SG, or CC
Crankcase Oil Capacity, qt (L) ............... 1.50 (1.42)
Air Cleaner Oil Bath Capacity, pt (L) ............... 0.50 (0.24)

Service Intervals

Change engine oil ............... Every 50 hours
Inspect air cleaner ............... Every 8 hours
Service air cleaner ............... Every 50 hours
Clean fuel strainer ............... Every 50 hours
Valve clearance adjustment ............... Every 150 hours
Fuel system inspection ............... Every 100 hours
Clean spark plug ............... Every 100 hours
Replace spark plug ............... Every 300 hours
Clean cooling fin ............... Every 50 hours
Flush/Clean fuel tank ............... Every 500 hours
Change reduction gear oil ............... Every 500 hours

Service Specifications

Cylinder Bore Inside Diameter, in (mm) ............... 3.0000-3.0005 (76.200-76.213)
Cylinder Maximum Out-of-Round, in (mm) ............... 0.0030 (0.076)
Crankshaft End Play Clearance, in (mm) ............... 0.004-0.006 (0.10-0.15)
Connecting Rod Journal Diameter, in (mm) ............... 1.375 (34.925)
Crankpin Journal Clearance, in (mm) ............... 0.0008-0.0020 (0.020-0.051)
Connecting Rod Side Clearance, in (mm) ............... 0.0050-0.0100 (0.127-0.254)
Piston to Cylinder Wall Clearance, in (mm) ............... 0.0035-0.0045 (0.089-0.114)
Piston Pin Bore Inside Diameter, in (mm) ............... 0.7502-0.7504 (19.055-19.060)
Piston Pin to Con Rod Bushing Clearance, in (mm) ............... 0.0003-0.0007 (0.008-0.018)
Top Ring Groove Width, in (mm) ............... 0.1240-0.1250 (3.150-3.175)
Second Ring Groove Width, in (mm) ............... 0.1240-0.1250 (3.150-3.175)
Third Ring Groove Width, in (mm) ............... 0.1240-0.1250 (3.150-3.175)
Oil Ring Groove Width, in (mm) ............... 0.1865-0.1875 (4.737-4.763)
Top Ring Groove Side Clearance, in (mm) ............... 0.0020-0.0035 (0.051-0.089)
Second Ring Groove Side Clearance, in (mm) ............... 0.0015-0.0030 (0.038-0.076)
Third Ring Groove Side Clearance, in (mm) ............... 0.0015-0.0030 (0.038-0.076)
Oil Ring Groove Side Clearance, in (mm) ............... 0.0015-0.0030 (0.038-0.076)
Piston Ring End Gap, in (mm) ............... 0.0070-0.0120 (0.178-0.305)
Intake Valve Head Diameter, in (mm) ............... 1.250 (31.75)
Exhaust Valve Head Diameter, in (mm) ............... 1.125 (28.575)
Valve Guide Inside Diameter, in (mm) ............... 0.3125-0.3135 (7.938-7.963)
Intake Valve Stem Outer Diameter, in (mm) ............... 0.3110-0.3115 (7.900-7.912)
Exhaust Valve Stem Outer Diameter, in (mm) ............... 0.3105-0.3110 (7.887-7.900)
Intake Valve Stem to Guide Clearance, in (mm) ............... 0.0015-0.0035 (0.038-0.089)
Exhaust Valve Stem to Guide Clearance, in (mm) ............... 0.0030-0.0050 (0.076-0.127)
Valve Face Angle, degrees ............... 45
Valve Seat Angle, degrees ............... 45
Valve Spring Free Length, in (mm) ............... 1.875 (47.63)
Camshaft Journal Diameter (Front), in (mm) ............... 1.3750-1.3755 (34.925-34.938)
Camshaft Journal Diameter (Rear), in (mm) ............... 1.1250-1.1255 (28.575-28.588)
Camshaft Bearing Clearance, in (mm) ............... 0.0015-0.0035 (0.038-0.089)
Camshaft End Play, in (mm) ............... 0.0020-0.0060 (0.051-0.152)
Camshaft Journal Clearance (Front), in (mm) ............... 0.0015-0.0035 (0.038-0.089)
Camshaft Journal Clearance (Rear), in (mm) ............... 0.0010-0.0030 (0.025-0.076)

Tightening Torques

Cylinder Head Stud Fasteners, lb-ft (Nm) ............... 28.0-32.0 (37.9-43.4)
Connecting Rod Bolt Nut, lb-ft (Nm) ............... 22.0-26.0 (29.8-35.3)
Flywheel Assembly Center Nut, lb-ft (Nm) ............... 90.0-100.0 (122.0-135.6)
Main Bearing Nut Fasteners, lb-ft (Nm) ............... 42.0-48.0 (56.9-65.1)
Crankcase Cover Assembly Bolt, lb-ft (Nm) ............... 20.0-24.0 (27.1-32.5)
Spark Plug Shell Seating Component, lb-ft (Nm) ............... 24.0-28.0 (32.5-37.9)
Magneto Mounting Base Attachment Screws, lb-ft (Nm) ............... 16.0-20.0 (21.7-27.1)
Governor Housing Retaining Screw, lb-ft (Nm) ............... 8.0-10.0 (10.8-13.6)
Oil Pan Sump Base Drainage Plug, lb-ft (Nm) ............... 18.0-22.0 (24.4-29.8)
Intake Exhaust Manifold Clamp Nuts, lb-ft (Nm) ............... 14.0-18.0 (19.0-24.4)
Valve Cover Fastener Gasket Retainer, lb-ft (Nm) ............... 4.0-6.0 (5.4-8.1)
Air Shroud Sheet Metal Screw Fasteners, lb-ft (Nm) ............... 5.0-7.0 (6.8-9.5)
Fuel Mechanical Pump Mounting Fasteners, lb-ft (Nm) ............... 12.0-15.0 (16.3-20.3)
Gear Cover Plate Threaded Fasteners, lb-ft (Nm) ............... 18.0-22.0 (24.4-29.8)
Cylinder Block Cross Tie Hardware Elements, lb-ft (Nm) ............... 35.0-40.0 (47.4-54.2)
Breather Assembly Retaining Nut, lb-ft (Nm) ............... 6.0-8.0 (8.1-10.8)
Exhaust Muffler Pipe Engagement Connection, lb-ft (Nm) ............... 40.0-50.0 (54.2-67.8)
Starter Motor Frame Mounting Nuts, lb-ft (Nm) ............... 30.0-35.0 (40.7-47.4)

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• Wisconsin Engines Specs
  
• Wisconsin AEN Specs
  
• Wisconsin AENL Specs
  
• Wisconsin AGND Specs
  
• Wisconsin AKN Specs
  
• Wisconsin AKS Specs
  
• Wisconsin BKN Specs
  

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