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Continental F226 Engine

The Continental F226 is a heavy-duty, 226 cubic-inch (3.7L) liquid-cooled inline six-cylinder internal combustion gasoline engine designed by Continental Motors. Engineered with a classic L-head (flathead or side-valve) architecture, this engine became a reliable staple across industrial, agricultural, and automotive sectors. It is widely recognized for powering vintage agricultural machinery like the Massey Harris 44-6 tractor and the Cletrac AG-6 crawler, as well as an array of early forklifts, power units, and specialized transport vehicles. Valued for its simplistic mechanical footprint and robust casting, the engine is celebrated by service technicians for its durability and exceptional parts longevity, frequently executing reliable restarts even after prolonged periods of storage.

Bore: 3.3125 inches (84.14 mm). Stroke: 4.375 inches (111.13 mm). Total Piston Displacement: 226 cubic inches (3.7 Liters). Cylinder Arrangement: 6-cylinder, inline. Firing Order: 1-5-3-6-2-4. Valve Design: L-Head (side-valve arrangement alongside the cylinders). Valve Face Angle: 45 degrees. Lubrication System: Full pressure force-feed system powered by an internal gear-type oil pump. Cooling System: Liquid-cooled with positive force circulation. Circulation Mechanism: Centrifugal belt-driven water pump driving coolant through integrated cylinder block and cylinder head water jackets.

Fuel System: Single-barrel updraft or downdraft carburetor configurations, typically utilizing Tillotson or Zenith fuel systems. Air Filtration: Relies on a heavy-duty oil-bath type air cleaner to trap incoming debris. Fuel Regulation: Directly managed via a mechanical flyweight governor coupled to the carburetor throttle linkage to automatically compensate for variable load changes. Supply Delivery: Fuel delivery can be handled through gravity-feed methods or via a mechanical fuel pump affixed directly to the integrated mounting pad on the side of the engine block. The induction layout allows the block to be seamlessly adapted for gasoline, natural gas, or liquid propane gas (LPG) operations.

General Technical Data

Engine Specifications

Engine Model ............... Continental F226
Engine Type ............... 4-cycle inline 6-cylinder liquid-cooled gasoline
Number of Cylinders ............... 6
Cylinder Arrangement ............... In-line vertical
Valve Configuration ............... L-head side-valve flathead
Engine Bore, in (mm) ............... 3.3125 (84.14)
Engine Stroke, in (mm) ............... 4.3750 (111.13)
Displacement, cu.in (L) ............... 226 (3.7)
Rated Engine Power, hp (kW) ............... 45-55 (33.5-41.0) at 1500 rpm
Automotive Peak Power, hp (kW) ............... 120 (89.5) at 3900 rpm
Rated Engine Speed, rpm ............... 1500-2400
Maximum Governor Speed, rpm ............... 2400
Idle Speed, rpm ............... 400-600
Peak Industrial Torque, lb-ft (Nm) ............... 170 (230) at 1200 rpm
Peak High-Output Torque, lb-ft (Nm) ............... 200 (271) at 1900 rpm
Compression Ratio, Standard ............... 6.0:1-6.5:1
Compression Ratio, High-Output ............... 8.1:1
Firing Order ............... 1-5-3-6-2-4
Rotation Direction ............... Counter-clockwise facing flywheel
Cylinder Block Material ............... Cast iron
Cylinder Head Material ............... Cast iron
Crankcase Construction ............... Monoblock cast integral with cylinders
Number of Main Bearings ............... 4
Lubrication System Type ............... Full-pressure gear pump
Cooling System Type ............... Liquid-cooled centrifugal pump
Ignition System Type ............... Battery-distributor or magneto
Spark Plug Model ............... Champion D16 or AC C85
Electrical System ............... 6V or 12V

Fuel System

Fuel Type ............... Gasoline or LPG conversion
Carburetor Model (Std) ............... Marvel Schebler TSX series
Carburetor Model (Opt) ............... Tillotson YR series
Throat Diameter (Std), in (mm) ............... 1.25 (31.75)
Throat Diameter (Opt), in (mm) ............... 1.125 (28.57)
High-Performance Carburetor ............... Weber 38 DGES twin-barrel
Choke Control Type ............... Manual cable-operated or thermal automatic
Governor System Type ............... Mechanical centrifugal flyball type
Governor Drive Arrangement ............... Gear-driven from camshaft gear
Fuel Delivery Method ............... Mechanical diaphragm pump or gravity feed
Fuel Pump Operating Pressure, psi (bar) ............... 2.5-4.5 (0.17-0.31)
Air Cleaner Configuration ............... Oil bath heavy-duty
Air Cleaner Manufacturer ............... Donaldson
Intake Manifold Material ............... Cast iron integral heat riser design
Exhaust Manifold Material ............... Cast iron rear or center dump outlet
Manifold Pre-Heater Type ............... Adjustable seasonal heat control valve
LPG Regulator Inlet Pressure Maximum, psi (bar) ............... 250 (17.2)
LPG Vaporizer Working Pressure, psi (bar) ............... 0.5 (0.034)

Dimensions and Weight

Overall Length, in (mm) ............... 32.1 (815)
Overall Width, in (mm) ............... 19.7 (500)
Overall Height, in (mm) ............... 28.5 (725)
Dry Weight, lbs (kg) ............... 415 (188)
Wet Weight, lbs (kg) ............... 465 (211)

Maintenance Data

Service Information

Compression Pressure, psi (bar) ............... 115-120 (7.9-8.3)
Compression Variation Between Cylinders, psi (bar) ............... 10 (0.69)
Normal Operating Oil Pressure, psi (bar) ............... 30-45 (2.07-3.10)
Minimum Hot Idle Oil Pressure, psi (bar) ............... 7-10 (0.48-0.69)
Normal Operating Temperature, F (C) ............... 160-180 (71.1-82.2)
Thermostat Opening Temperature, F (C) ............... 150 (65.5)
Thermostat Fully Open Temperature, F (C) ............... 172 (77.8)
Oil Pump Pressure Relief Valve Setting, psi (bar) ............... 40-45 (2.76-3.10)
Spark Plug Gap, in (mm) ............... 0.022-0.025 (0.56-0.64)
Breaker Point Gap, in (mm) ............... 0.020 (0.51)
Ignition Timing Setting ............... 0 deg TDC at 400 rpm
Full Advance Ignition Timing ............... 22 deg BTDC at 2000 rpm
Cooling Fan Belt Deflection, in (mm) ............... 0.75 (19.05)
Intake Valve Clearance, Hot, in (mm) ............... 0.014 (0.356)
Exhaust Valve Clearance, Hot, in (mm) ............... 0.016 (0.406)
Intake Valve Clearance, Cold, in (mm) ............... 0.016 (0.406)
Exhaust Valve Clearance, Cold, in (mm) ............... 0.018 (0.457)

Engine Oil and Coolant

Engine Oil Type ............... SAE 20W, SAE 30, 10W-30
API Service Classifications ................. SF, SG
Crankcase Oil Capacity Base, qt (L) ............... 7.0 (6.6)
Crankcase Oil Capacity with Filter, qt (L) ............... 8.0 (7.6)
Cooling System Fluid Capacity, qt (L) ............... 18.0-20.0 (17.0-18.9)

Service Intervals

Change oil and filter ............... Every 100 hours
Replace/clean fuel filters ............... Every 150 hours
Inspect air cleaner ............... Every 20 hours
Change air cleaner oil ............... Every 50 hours
Change coolant ............... Every 500 hours
Valve-lash adjustment ............... Every 300 hours
Distributor point inspection ............... Every 300 hours
Spark plug replacement ............... Every 500 hours
Compression test evaluation ............... Every 500 hours
Belt tension verification ............... Every 300 hours
Check ignition timing ............... Every 300 hours

Service Specifications

Cylinder Bore Standard Diameter, in (mm) ............... 3.3125-3.3145 (84.138-84.188)
Cylinder Bore Maximum Taper, in (mm) ............... 0.003 (0.076)
Cylinder Bore Maximum Out of Round, in (mm) ............... 0.002 (0.051)
Cylinder Head Flatness Deflection Across Block, in (mm) ............... 0.003 (0.076)
Cylinder Block Top Surface Flatness, in (mm) ............... 0.003 (0.076)
Crankshaft Main Journal Diameter, in (mm) ............... 2.3744-2.3752 (60.31-60.33)
Crankpin Rod Journal Diameter, in (mm) ............... 2.0619-2.0627 (52.37-52.39)
Main Bearing Shell Journal Clearance, in (mm) ............... 0.0012-0.0032 (0.030-0.081)
Main Bearing Shell Max Allowable Wear Limit, in (mm) ............... 0.0045 (0.114)
Crankshaft End Play Axial Thrust Limit, in (mm) ............... 0.004-0.008 (0.102-0.203)
Connecting Rod Journal Bearing Clearance, in (mm) ............... 0.0010-0.0027 (0.025-0.069)
Connecting Rod Side Play, in (mm) ............... 0.005-0.010 (0.127-0.254)
Piston to Cylinder Wall Clearance, in (mm) ............... 0.0025-0.0035 (0.064-0.089)
Piston Pin Bore Diameter in Piston Skirt, in (mm) ............... 0.8592-0.8594 (21.824-21.829)
Piston Pin Diameter, in (mm) ............... 0.8589-0.8591 (21.816-21.821)
Piston Pin Fit Clearance in Piston Boss, in (mm) ............... 0.0001-0.0003 (0.0025-0.0076)
Piston Pin Fit Clearance in Con Rod Bushing, in (mm) ............... 0.0002-0.0005 (0.0051-0.0127)
Top Ring Groove Width, in (mm) ............... 0.1260-0.1270 (3.200-3.226)
Second Ring Groove Width, in (mm) ............... 0.1260-0.1270 (3.200-3.226)
Oil Ring Groove Width, in (mm) ............... 0.2510-0.2520 (6.375-6.401)
Top Ring End Gap, in (mm) ............... 0.008-0.018 (0.203-0.457)
Second Ring End Gap, in (mm) ............... 0.008-0.015 (0.203-0.381)
Oil Ring End Gap, in (mm) ............... 0.008-0.018 (0.203-0.457)
Top Ring Side Clearance, in (mm) ............... 0.002-0.004 (0.051-0.102)
Second Ring Side Clearance, in (mm) ............... 0.002-0.004 (0.051-0.102)
Oil Ring Side Clearance, in (mm) ............... 0.001-0.003 (0.025-0.076)
Intake Valve Head Outside Diameter, in (mm) ............... 1.485 (37.72)
Exhaust Valve Head Outside Diameter, in (mm) ............... 1.328 (33.73)
Intake Valve Seat Angle, deg ............... 30
Exhaust Valve Seat Angle, deg ............... 45
Intake Valve Stem Outer Diameter, in (mm) ............... 0.3405-0.3415 (8.65-8.67)
Exhaust Valve Stem Outer Diameter, in (mm) ............... 0.3395-0.3405 (8.62-8.65)
Intake Valve Stem to Guide Clearance, in (mm) ............... 0.0015-0.0030 (0.038-0.076)
Exhaust Valve Stem to Guide Clearance, in (mm) ............... 0.0025-0.0040 (0.064-0.102)
Valve Spring Free Length, in (mm) ............... 2.125 (53.97)
Valve Tappet Guide to Tappet Stem Clearance, in (mm) ............... 0.0005-0.0020 (0.012-0.051)
Camshaft Journal Diameter (Front), in (mm) ............... 1.9990-1.9995 (50.77-50.79)
Camshaft Journal Diameter (Center), in (mm) ............... 1.9365-1.9370 (49.19-49.20)
Camshaft Journal Diameter (Rear), in (mm) ............... 1.3745-1.3750 (34.91-34.92)
Cam Lobe Lift (Intake), in (mm) ............... 0.265 (6.73)
Cam Lobe Lift (Exhaust), in (mm) ............... 0.265 (6.73)
Camshaft Journal Bearing Clearance, in (mm) ............... 0.0010-0.0030 (0.025-0.076)
Camshaft End Play, in (mm) ............... 0.003-0.007 (0.076-0.178)

Tightening Torques

Cylinder Head Stud Nuts (3/8-16), lb-ft (Nm) ............... 35-40 (47.5-54.2)
Cylinder Head Stud Nuts (7/16-14), lb-ft (Nm) ............... 55-60 (74.6-81.3)
Cylinder Head Automotive Fastener, lb-ft (Nm) ............... 30-35 (40.7-47.5)
Main Bearing Cap Bolts (Standard), lb-ft (Nm) ............... 35-40 (47.5-54.2)
Main Bearing Cap Bolts (Heavy Duty), lb-ft (Nm) ............... 70-75 (94.9-101.7)
Connecting Rod Cap Nuts, lb-ft (Nm) ............... 45-50 (61.0-67.8)
Flywheel to Crankshaft Mounting Bolts, lb-ft (Nm) ............... 55-60 (74.6-81.3)
Crankshaft Front Pulley Damper Bolt, lb-ft (Nm) ............... 65-70 (88.1-94.9)
Camshaft Gear Nut (Cast Iron Shaft), lb-ft (Nm) ............... 65-70 (88.1-94.9)
Camshaft Gear Nut (Forged Steel Shaft), lb-ft (Nm) ............... 120-125 (162.7-169.5)
Camshaft Thrust Plate Screws, lb-ft (Nm) ............... 15-18 (20.3-24.4)
Manifold to Cylinder Block Clamp Nuts, lb-ft (Nm) ............... 25-30 (33.9-40.7)
Oil Pan Sump Drain Fasteners, lb-ft (Nm) ............... 12-15 (16.3-20.3)
Oil Pump Assembly Body Mounting Fasteners, lb-ft (Nm) ............... 15-18 (20.3-24.4)
Oil Pump Cover Plate Small Screws, lb-ft (Nm) ............... 7-9 (9.5-12.2)
Water Pump Assembly Shell to Block Bolts, lb-ft (Nm) ............... 15-18 (20.3-24.4)
Water Pump Body Impeller Retaining Nut, lb-ft (Nm) ............... 25-30 (33.9-40.7)
Front Timing Gear Cover Plate Bolts, lb-ft (Nm) ............... 12-15 (16.3-20.3)
Flywheel Housing Mounting Bolts, lb-ft (Nm) ............... 35-40 (47.5-54.2)
Spark Plug Base Screwed into Cast Iron, lb-ft (Nm) ............... 28-32 (38.0-43.4)
Distributor Base Clamp Lock Bracket Screw, lb-ft (Nm) ............... 10-12 (13.6-16.3)
Fuel Diaphragm Pump Body Flange Base Fasteners, lb-ft (Nm) ............... 12-15 (16.3-20.3)
Governor Housing Attachment Mounting Screws, lb-ft (Nm) ............... 15-18 (20.3-24.4)

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• Continental Engines Specs
  
• Continental Z120 Specs
  
• Continental Z120 Specs
  
• Continental Z120 Specs
  
• Continental Z120 Specs
  
• Continental F227 Specs
  
• Continental F244 Specs
  
• Continental F245 Specs
  

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