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International C152 Engine

The International Harvester C152 is a heavy-duty, inline four-cylinder, four-stroke internal combustion engine developed primarily for agricultural application. Notably utilized as the standard powerplant for the Farmall H row-crop tractor (produced from 1939 to 1954), the engine gained a reputation for extreme reliability, ease of in-field service, and structural adaptability. Originally engineered to accommodate varying fuel qualities common to the era (including gasoline, kerosene, and tractor distillate) the motor utilizes a cast-iron block design with removable wet cylinder sleeves to facilitate straightforward overhauls.

The engine utilizes an overhead valve (OHV) configuration featuring two valves per cylinder actuated by pushrods and rocker arms driven from a gear-driven camshaft. Valve clearance adjustments must be performed under hot operating conditions. The total engine displacement is 152.1 cubic inches (2.5 liters). The factory cylinder bore specification is 3.375 inches (86 mm), and the piston stroke is 4.25 inches (108 mm). The standard base compression ratio is configured at 5.9:1 for gasoline operations.

Fuel delivery relies on a gravity-fed or low-pressure mechanical architecture depending on the specific chassis installation. The fuel-air mixture is regulated by a single-barrel updraft carburetor attached to an induction manifold. Depending on factory configuration, the system may include dual-fuel manifolds (for kerosene/distillate models) that utilize exhaust heat to preheat heavier fuel blends before entry into the combustion chambers.

Lubrication is managed via a wet-sump system pressurized by an internal oil pump. The system features a bypass-type oil filter assembly and utilizes structural crankcase breathing via a dedicated ventilation tube running from the cylinder head to the air cleaner intake assembly to regulate internal pressure. The engine uses a liquid-cooled thermal management loop. Coolant circulation is pressurized by a front-mounted water pump, routing fluid through the cylinder block jackets and an external radiator setup.

General Technical Data

Engine Specifications

Engine Model ............... International Harvester C152
Engine Type ............... 4-cycle inline 4-cylinder overhead valve liquid-cooled gasoline engine
Number of Cylinders ............... 4
Cylinder Arrangement ............... In-line
Engine Bore, in (mm) ............... 3.375 (85.7)
Engine Stroke, in (mm) ............... 4.250 (108.0)
Displacement, cu.in (L) ............... 152.1 (2.5)
Rated Engine Power, hp (kW) ............... 26.0 (19.4)
Maximum Drawbar Power, hp (kW) ............... 24.17 (18.02)
Maximum Belt Power, hp (kW) ............... 26.20 (19.54)
Rated Engine Speed, rpm ............... 1650
Low Idle Speed, rpm ............... 425-475
High Idle Speed, rpm ............... 1815-1845
Peak Torque, lb-ft (Nm) ............... 95.0 (128.8) at 1200 rpm
Compression Ratio (Gasoline) ............... 5.9:1
Compression Ratio (Kerosene) ............... 4.4:1
Firing Order ............... 1-3-4-2
Cylinder Block Material ............... Cast iron
Cylinder Head Material ............... Cast iron
Cylinder Liners Type ............... Dry cast iron replaceable sleeves
Number of Main Bearings ............... 3
Lubrication System Type ............... Full-pressure gear-driven circulation
Oil Pump Type ............... Internal gear driven from camshaft
Oil Filter Type ............... Replaceable element bypass style
Cooling System Type ............... Thermo-siphon assisted centrifugal water pump forced circulation
Water Pump Type ............... Belt-driven centrifugal impeller style
Cooling Fan Blades Number ............... 4
Cooling Fan Drive Type ............... V-belt from crankshaft pulley
Air Cleaner Type ............... Oil bath with secondary wire mesh element
Ignition System Type ............... Magneto or battery distributor system
Magneto Model Option ............... International Harvester H4
Distributor Model Option ............... International Harvester Type D10
Spark Plug Gap, in (mm) ............... 0.025 (0.635)
Breaker Point Gap, in (mm) ............... 0.013 (0.330)
Starting System ............... Electric starter motor with auxiliary manual crank options
Electrical System Ground ............... Positive ground
Electrical System Voltage, V ............... 6

Fuel System

Fuel System Type ............... Gravity flow updraft carburetor feed
Carburetor Manufacturer ............... International Harvester or Zenith
Carburetor Model Number ............... IH 3/4-inch or Zenith 161X7
Carburetor Throat Diameter, in (mm) ............... 1.000 (25.4)
Carburetor Venturi Size, in (mm) ............... 0.781 (19.8)
Main Jet Size Standard ............... 0.047 (1.19)
Idle Jet Size Standard ............... 0.025 (0.63)
Choke Bore Diameter, in (mm) ............... 1.125 (28.6)
Fuel Tank Capacity, gal (L) ............... 13.0 (49.2)
Auxiliary Gasoline Starting Tank Capacity, gal (L) ............... 1.0 (3.8)
Fuel Filter Type ............... Sediment bowl assembly with fine brass screen mesh
Sediment Bowl Glass Diameter, in (mm) ............... 2.000 (50.8)
Fuel Delivery Pressure ............... Gravity static head pressure
Governor Type ............... Flyball mechanical centrifugal type running in oil bath
Governor Drive ............... Gear driven from timing gear train
Choke Control Cable Type ............... Solid wire push-pull casing
Air Intake Pipe Diameter, in (mm) ............... 1.750 (44.45)
Manifold Type ............... Combination intake and exhaust heat riser assembly
Manifold Heat Control ............... Adjustable deflector shield for alternative fuels

Dimensions and Weight

Length Overall, in (mm) ............... 32.5 (825)
Width Overall, in (mm) ............... 21.3 (540)
Height Overall, in (mm) ............... 34.8 (880)
Dry Weight Base Config, lbs (kg) ............... 520 (235)
Wet Weight with Oil and Coolant, lbs (kg) ............... 565 (255)

Maintenance Data

Service Information

Compression Pressure Minimum Cranking, psi (bar) ............... 110.0 (7.58)
Compression Variation Maximum Between Cylinders, psi (bar) ............... 10.0 (0.69)
Oil Pressure Normal Rated Speed, psi (bar) ............... 30.0-35.0 (2.06-2.41)
Oil Pressure Minimum Low Idle, psi (bar) ............... 10.0 (0.69)
Coolant Operating Temperature Standard, F (C) ............... 165.0-185.0 (73.8-85.0)
Fan Belt Deflection Pressed Midpoint, in (mm) ............... 0.750 (19.05)
Intake Valve Clearance, in (mm) ............... 0.017-0.019 (0.432-0.483)
Exhaust Valve Clearance, in (mm) ............... 0.017-0.019 (0.432-0.483)

Engine Oil and Coolant

Engine Oil Type .................. SAE 30, SAE 10W, or 10W-30
API Service Classifications ......................... SF/CC or higher
Engine Oil Crankcase Capacity, qts (L) ............... 6.0 (5.7)
Cooling System Liquid Capacity, qts (L) ............... 16.5 (15.6)
Air Cleaner Oil Sump Capacity, qts (L) ............... 1.0 (0.95)

Service Intervals

Change oil and filter ............... Every 100 hours
Inspect air filter ............... Every 50 hours
Valve clearance adjustment ............... Every 500 hours
Fuel system inspection ............... Every 1000 hours
Change coolant ............... Every 1000 hours
Spark plug replacement ............... Every 500 hours
Check ignition system ............... Every 500 hours

Service Specifications

Cylinder Sleeve Bore Wear Limit Out of Round, in (mm) ............... 0.005 (0.127)
Cylinder Sleeve Taper Maximum Allowable, in (mm) ............... 0.006 (0.152)
Crankshaft Main Journal Diameter (Front), in (mm) ............... 2.498 (63.45)
Crankshaft Main Journal Diameter (Center), in (mm) ............... 2.498 (63.45)
Crankshaft Main Journal Diameter (Rear), in (mm) ............... 2.498 (63.45)
Crankshaft End Play, in (mm) ............... 0.004-0.008 (0.102-0.203)
Main Bearing Journal Clearance (Std), in (mm) ............... 0.0015-0.0035 (0.038-0.089)
Main Bearing Journal Clearance (Wear Limit), in (mm) ............... 0.005 (0.127)
Connecting Rod Journal Diameter, in (mm) ............... 2.480 (62.99)
Connecting Rod Bearing Journal Clearance (Standard), in (mm) ............... 0.0015-0.0030 (0.038-0.076)
Connecting Rod Bearing Journal Clearance (Max Limit), in (mm) ............... 0.0045 (0.114)
Camshaft Journal Bearing Clearance (N1), in (mm) ............... 0.0015-0.0035 (0.038-0.089)
Camshaft Journal Bearing Clearance (N2), in (mm) ............... 0.0020-0.0040 (0.051-0.102)
Camshaft Journal Bearing Clearance (N3), in (mm) ............... 0.0020-0.0040 (0.051-0.102)
Camshaft Journal Diameter (N1), in (mm) ............... 1.875 (47.62)
Camshaft Journal Diameter (N2), in (mm) ............... 1.843 (46.81)
Camshaft Journal Diameter (N3), in (mm) ............... 1.781 (45.23)
Cylinder Head Surface Flatness Max Distortion, in (mm) ............... 0.004 (0.102)
Intake Valve Head Outer Diameter, in (mm) ............... 1.515 (38.48)
Exhaust Valve Head Outer Diameter, in (mm) ............... 1.390 (35.31)
Intake Valve Stem Diameter, in (mm) ............... 0.371 (9.42)
Exhaust Valve Stem Diameter, in (mm) ............... 0.370 (9.39)
Intake Valve Seat Angle (Intake), deg ............... 45
Exhaust Valve Seat Angle (Exhaust), deg ............... 45
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) ............... 2.312 (58.72)
Piston Pin Diameter, in (mm) ............... 1.109 (28.16)
Piston to Cylinder Sleeve Clearance (Std), in (mm) ............... 0.0035-0.0045 (0.089-0.114)
Piston to Cylinder Sleeve Clearance (Wear Limit), in (mm) ............... 0.008 (0.203)
Piston Pin to Piston Bushing Clearance, in (mm) ............... 0.0003-0.0007 (0.008-0.018)
Piston Pin to Connecting Rod Bushing Clearance, in (mm) ............... 0.0005-0.0009 (0.013-0.023)
Top Ring Groove Clearance, in (mm) ............... 0.0020-0.0035 (0.051-0.089)
Second Ring Groove Clearance, in (mm) ............... 0.0015-0.0030 (0.038-0.076)
Oil Ring Groove Clearance, in (mm) ............... 0.0015-0.0030 (0.038-0.076)
Top Ring End Gap, in (mm) ............... 0.007-0.017 (0.178-0.432)
Second Ring End Gap, in (mm) ............... 0.007-0.017 (0.178-0.432)
Oil Ring End Gap, in (mm) ............... 0.007-0.017 (0.178-0.432)
Rocker Arm Shaft Outside Diameter, in (mm) ............... 0.748 (19.00)
Rocker Arm Bushing Inside Diameter, in (mm) ............... 0.750 (19.05)
Rocker Arm to Shaft Clearance, in (mm) ............... 0.001-0.003 (0.025-0.076)

Tightening Torque Specs

Cylinder Head Cap Screws, lb-ft (Nm) ............... 70.0 (95.0)
Connecting Rod Bearing Cap Bolts, lb-ft (Nm) ............... 48.0 (65.0)
Main Bearing Cap Stud Nuts, lb-ft (Nm) ............... 80.0 (108.5)
Flywheel to Crankshaft Cap Screws, lb-ft (Nm) ............... 55.0 (74.6)
Flywheel Housing to Cylinder Block Cap Screws, lb-ft (Nm) ............... 35.0 (47.5)
Crankshaft Front Pulley Nut, lb-ft (Nm) ............... 110.0 (149.1)
Camshaft Thrust Plate Retaining Cap Screws, lb-ft (Nm) ............... 18.0 (24.4)
Timing Gear Case Cover Cap Screws, lb-ft (Nm) ............... 22.0 (29.8)
Rocker Arm Shaft Bracket Cap Screws, lb-ft (Nm) ............... 30.0 (40.7)
Valve Rocker Arm Cover Acorn Nuts, lb-ft (Nm) ............... 8.0 (10.8)
Oil Pan Drain Plug, lb-ft (Nm) ............... 35.0 (47.5)
Oil Pan to Cylinder Block Fixing Screws, lb-ft (Nm) ............... 14.0 (19.0)
Oil Pump Assembly to Cylinder Block Bolts, lb-ft (Nm) ............... 22.0 (29.8)
Oil Pump Cover Plate Screws, lb-ft (Nm) ............... 9.0 (12.2)
Manifold Assembly to Cylinder Head Stud Nuts, lb-ft (Nm) ............... 25.0 (33.9)
Carburetor Flange Mounting Stud Nuts, lb-ft (Nm) ............... 15.0 (20.3)
Governor Housing to Block Fixing Bolt, lb-ft (Nm) ............... 18.0 (24.4)
Spark Plugs, lb-ft (Nm) ............... 30.0 (40.7)
Water Pump Assembly to Block Cap Screws, lb-ft (Nm) ............... 22.0 (29.8)
Water Outlet Elbow to Cylinder Head Bolts, lb-ft (Nm) ............... 22.0 (29.8)
Fan Bracket Adjustment Hex Bolt, lb-ft (Nm) ............... 35.0 (47.5)
Magneto or Distributor Flange Clamp Bolts, lb-ft (Nm) ............... 14.0 (19.0)
Starter Motor Mounting Flange Hex Bolts, lb-ft (Nm) ............... 40.0 (54.2)
Generator Support Arm Adjusting Bolt, lb-ft (Nm) ............... 15.0 (20.3)
Front Engine Support Mount Base Bolts, lb-ft (Nm) ............... 65.0 (88.1)
Rear Engine Support Face Plate Housing Bolts, lb-ft (Nm) ............... 65.0 (88.1)
Oil Filter Base Assembly Center Bolt, lb-ft (Nm) ............... 28.0 (38.0)
Crankcase Breather Tube Bracket Screw, lb-ft (Nm) ............... 10.0 (13.6)
Air Cleaner Mounting Bracket Band Bolt, lb-ft (Nm) ............... 14.0 (19.0)
Fuel Sediment Bowl Metal Clamp Ring Nut, lb-in (Nm) ............... 45.0 (5.1)
Governor Lever Arm Pin Clamp Screw, lb-in (Nm) ............... 60.0 (6.8)
Tappet Cover Side Plate Hold Down Screws, lb-ft (Nm) ............... 8.0 (10.8)
Flywheel Housing Inspection Plate Screws, lb-in (Nm) ............... 80.0 (9.0)
Timing Pointer Plate Small Machine Screws, lb-in (Nm) ............... 35.0 (4.0)

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• International Engines Specs
  
• International BC144 Specs
  
• International C113 Specs
  
• International C135 Specs
  
• International C153 Specs
  
• International C157 Specs
  

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