International C157 Specifications
| Engine Model: International Harvester C157 |
| Engine Type: 4-stroke in-line 4-cylinder liquid-cooled gasoline |
| Total Displacement: 157.1 cu.in (2.57 L) |
| Rated Engine Power: 60-64 Hp (45-48 kW) at 2400 rpm |
| Fuel System Type: Updraft carburetor |
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The International C157 is a 2.6-liter,
naturally aspirated, 4-cylinder gasoline engine produced by
International Harvester (IH) during the 1960s. This engine belongs to
the renowned C-series family, which was designed for robust utility and
agricultural service. The C157 was primarily developed as a powerplant
for utility tractors, most notably the International 544 and its
industrial derivative, the 2544. It served as a larger-displacement
alternative to the C-153, offering enhanced low-end torque essential for
drawbar and power take-off (PTO) applications.
The engine is characterized by its long-stroke design, with a stroke of
108.0 mm (4.250 in) exceeding the bore of 87.3 mm (3.438 in). This
undersquare configuration promotes high torque at low engine speeds, a
critical attribute for tractor duty cycles. The C157 features an
overhead valve (OHV) actuation via pushrods, a cast iron cylinder block,
and replaceable wet cylinder liners, making it serviceable in field
conditions.
While not a high-revving automotive engine, the C157 is revered for its
durability, simplicity, and the availability of replacement parts
through vintage tractor restoration networks. Its power output ranges
from 52 to 60 horsepower depending on the measurement point (PTO vs.
gross engine), with a torque peak occurring at a low 1,400 rpm,
reflecting its purpose as a lugging, high-traction power source.
The International C157 is a 4-stroke, in-line 4-cylinder gasoline power
unit. It is naturally aspirated without any supercharging or
turbocharging systems. The engine displacement measures 157.1 cu.in
(2.57 L). The bore and stroke dimensions are 87.3 mm x 108.0 mm (3.438
in x 4.250 in). The compression ratio is set at a low 7.5:1, permitting
the use of low-octane fuels under heavy load. The firing order is
1-3-4-2, a standard layout for in-line 4-cylinder engines to balance
primary and secondary forces.
Gross Horsepower (engine only): 45-48 kW (60-64 hp) @ 2,300-2,400 rpm
PTO Horsepower (tractor): 39-40 kW (52-54 hp) @ 2,300 rpm
Drawbar Horsepower (tractor): 34 kW (46 hp) @ rated load
Maximum Torque: 197 Nm (145 lb-ft) @ 1,400 rpm
Governed Speed (Tractor): 2,300 rpm
Governed Speed (Industrial Power Unit): 2,400 rpm
Idle Speed (Low): 450-500 rpm
Idle Speed (High, no load): 2,450 rpm
The cylinder block is constructed from cast iron, providing a rigid
foundation for the rotating assembly and a durable structure for
agricultural environments. The block features a deep-skirt design
extending below the crankshaft centerline, enhancing rigidity and
reducing torsional flex under heavy drawbar loads. A distinctive design
element of the C157 is the use of replaceable wet cylinder liners
(sleeves).
These sleeves are in direct contact with the engine coolant, providing
excellent heat transfer from the combustion chamber to the cooling
system. The wet sleeve design allows for field replacement of the
cylinder bore without requiring a complete engine block replacement, a
critical advantage for minimizing downtime in agricultural operations.
The crankshaft is supported by three main bearings. The crankshaft is
forged from high-carbon steel, with induction-hardened journal surfaces.
The connecting rods are forged steel, machined as a matched set with the
cap. The pistons are cast aluminum alloy with a tin-plated skirt
surface. Each piston is fitted with three rings: two compression rings
(upper and intermediate) and one oil control ring positioned below the
piston pin. The piston pin is a full-floating type retained by spiral
locks.
The cylinder head is a separate cast iron component bolted to the
cylinder block. It houses the overhead valve (OHV) arrangement, with
valves arranged in a straight line along the head. The combustion
chamber is a wedge design, promoting turbulence for improved fuel mixing
at low engine speeds.
The valvetrain is actuated by a camshaft located in the cylinder block,
driven by helical-cut gears from the crankshaft. From the camshaft,
mechanical lifters (tappets) push hollow pushrods upward, which actuate
rocker arms mounted on a central shaft. The rocker arms then open the
valves against spring pressure. This configuration is simple, durable,
and easily serviceable with hand tools.
Both intake and exhaust valves are made from heat-resistant
silicon-chromium steel. The valve seats are induction-hardened directly
into the cylinder head casting for the intake side, while the exhaust
seats receive a hardened alloy steel insert to withstand higher
temperatures. The valve guides are integral to the cylinder head and are
reamable to size during overhaul. Valve lash adjustment is performed via
a setscrew and locknut on the rocker arm.
Valve Arrangement: Overhead valve, in-line, pushrod actuated
Number of Valves: 8 (2 per cylinder)
Intake Valve Diameter: 34.9 mm (1.374 in)
Exhaust Valve Diameter: 31.8 mm (1.250 in)
Valve Lift (intake and exhaust): 9.5 mm (0.375 in)
The fuel system employs an updraft carburetor mounted low on the engine,
drawing air upward through the throttle body and intake manifold. The
carburetor is either a Zenith or Marvel-Schebler unit, both
single-barrel designs optimized for stable fuel delivery across varying
load conditions. The updraft configuration allows fuel to be drawn from
a gravity-fed tank or a low-pressure mechanical fuel pump.
A critical component of the C157 fuel system is the mechanical flyweight
governor. The governor is gear-driven from the camshaft and is
integrated into the front of the engine. The governor senses engine
speed via centrifugal force acting on flyweights. As engine load
increases and speed drops, the governor opens the carburetor throttle
plate to maintain the preset governed speed.
Conversely, when load decreases, the governor closes the throttle. This
system maintains engine speed regardless of load, essential for
PTO-driven implements (e.g., mowers, balers). The fuel pump, where
fitted, is a mechanical diaphragm type mounted to the cylinder block.
Carburetor Type: Updraft, single-barrel (Zenith 68 or Marvel-Schebler
TSX)
Governor Type: Mechanical, centrifugal flyweight, variable speed
Fuel Pump Pressure: 14-21 kPa (2-3 psi)
Fuel Grade: 85-87 octane (R+M/2)
The lubrication system is a full-pressure, gear-type design. A positive
displacement oil pump, mounted inside the oil pan and driven by a shaft
from the distributor, draws oil through a wire mesh strainer. The pump
forces oil through a full-flow oil filter. After filtration, oil is
distributed to the main bearings, connecting rod bearings, camshaft
bearings, and through drilled passages to the rocker shaft assembly. The
valve train receives oil through hollow pushrods that feed the rocker
arms.
The oil pan is a stamped steel sump with a large capacity to accommodate
the engine’s sloped operation in agricultural terrain. A crankcase
breather (road draft tube) vents blow-by gases to the atmosphere, a
design standard for this era.
Oil Capacity (with filter): 5.7 L (6.0 U.S. qt)
Oil Pressure (operating, at rated speed): 172-276 kPa (25-40 psi)
Oil Pressure (hot idle minimum): 34 kPa (5 psi)
Recommended Oil Viscosity: SAE 30 (above 10°C / 50°F)
Recommended Oil Viscosity: SAE 10W-30 (multi-season)
Recommended Oil Viscosity: SAE 20W (below 10°C / 50°F)
Oil Filter Type: Full-flow, spin-on or cartridge (depending on
production year)
Oil Pump Type: Gear-type, crankshaft-driven via distributor shaft
The cooling system is a pressurized, liquid-cooled design using a
centrifugal water pump. The water pump is mounted on the front of the
cylinder block and is driven by a V-belt from the crankshaft pulley.
Coolant circulates from the lower radiator tank, through the water pump,
into the cylinder block water jackets, then upward into the cylinder
head, and finally out through the thermostat housing and upper radiator
hose. The replaceable wet cylinder liners are bathed directly in
coolant, ensuring efficient heat dissipation from the combustion zone.
The system incorporates a wax-pellet thermostat positioned in the
coolant outlet. A bypass circuit permits coolant to recirculate through
the block until the operating temperature is reached, preventing thermal
shock. The radiator is a vertical-flow, tube-and-fin design with a
removable pressure cap.
Coolant Capacity (engine and radiator): 13.2 L (14.0 U.S. qt).
Thermostat Opening Temperature: 82°C (180°F).
Thermostat Fully Open Temperature: 95°C (203°F).
Radiator Cap Pressure: 48 kPa (7 psi).
Water Pump Type: Centrifugal, sealed ball bearing with carbon-ceramic
seal.
Coolant Type: Low-silicate ethylene glycol antifreeze (green) mixed
50/50 with distilled water.
Electrical System: The C157 operates on a 12-volt electrical system with
negative ground. The ignition system is a battery-and-coil design
comprising a distributor, ignition coil, spark plugs, and a 12-volt
battery. The distributor houses the breaker points (contact points), a
condenser, and a centrifugal advance mechanism. The centrifugal advance
increases ignition timing from base idle timing to a full mechanical
advance as engine speed rises. A starter motor, mounted to the flywheel
housing, engages a ring gear on the flywheel. The charging system uses a
belt-driven, 12-volt generator (DC) with an external voltage regulator.
Later production units may feature an alternator.
Governor Integration: The mechanical governor is not an external add-on
but an integrated engine system. The governor control lever connects to
the operator’s throttle lever in the tractor cab. The governor then
overrides the throttle plate position to maintain the selected engine
speed under varying load.
Intake and Exhaust Manifolds: The intake and exhaust manifolds are
mounted on the same side of the cylinder head (right side when viewed
from the driver’s seat). On many C157 installations, the intake and
exhaust manifolds are cast as a single combined unit (siamesed) to use
exhaust heat to warm the intake air and fuel mixture, improving
cold-weather operation and fuel vaporization.
Overall Length (front of fan hub to flywheel face): 860 mm (33.9 in).
Overall Width (valve cover to oil pan): 560 mm (22.0 in).
Overall Height (top of air cleaner base to bottom of sump): 740 mm (29.1
in).
Dry Weight (complete engine with flywheel and manifolds): 211 kg (465
lb).
Weight (long block without accessories): 177 kg (390 lb).
Spark Plug Type: Champion D16 or Autolite 295
Spark Plug Gap: 0.64 mm (0.025 in)
Breaker Point Gap (new): 0.51 mm (0.020 in)
Breaker Point Dwell Angle: 31-34 degrees
Condenser Capacitance: 0.25-0.28 microfarads
Ignition Timing (initial, at idle): 3° BTDC
Ignition Timing (full mechanical advance): 28° BTDC @ 2,000 rpm
Valve Lash (hot, both intake and exhaust): 0.36 mm (0.014 in)
Valve Lash (cold, both intake and exhaust): 0.38 mm (0.015 in)
Spark Plug Replacement Interval: 300 hours of operation
Engine Oil Change Interval: 100 hours (severe dust conditions)
Engine Oil Change Interval: 200 hours (normal conditions)
Oil Filter Replacement Interval: Every second oil change (200-400 hours)
Coolant Replacement Interval: 2 years or 1,000 hours
Air Cleaner Service (oil bath type): Clean cup and replace oil monthly
(50-100 hours)
Valve Clearance Check Interval: 500 hours
Ignition Timing Check Interval: 500 hours
Cylinder Head Bolts: 108-122 Nm (80-90 lb-ft).
Connecting Rod Cap Bolts (3/8 in - 24 UNF): 61-68 Nm (45-50 lb-ft)
Main Bearing Cap Bolts (1/2 in - 13 UNC): 102-115 Nm (75-85 lb-ft)
Flywheel Bolts (5/8 in - 18 UNF): 75-88 Nm (55-65 lb-ft)
Flywheel Housing-to-Block Bolts (3/8 in - 16 UNC): 34-41 Nm (25-30
lb-ft)
Intake/Exhaust Manifold Nuts (3/8 in - 16 UNC): 27-34 Nm (20-25 lb-ft)
Rocker Arm Shaft Bracket Bolts (3/8 in - 16 UNC): 27-34 Nm (20-25 lb-ft)
Valve Cover Bolts (5/16 in - 18 UNC): 7-10 Nm (5-7 lb-ft)
Oil Pan Bolts (5/16 in - 18 UNC): 14-20 Nm (10-15 lb-ft)
Spark Plugs: 27-34 Nm (20-25 lb-ft)
Water Pump Mounting Bolts (3/8 in - 16 UNC): 27-34 Nm (20-25 lb-ft)
Camshaft Thrust Plate Bolts (5/16 in - 18 UNC): 14-18 Nm (10-13 lb-ft)
Carburetor Mounting Nuts (5/16 in - 18 UNC): 14-17 Nm (10-12 lb-ft)
Starter Motor Mounting Bolts (7/16 in - 14 UNC): 41-47 Nm (30-35 lb-ft)
The International C157 engine was utilized in the following agricultural
and industrial equipment manufactured by International Harvester.
1968-1973 International 544 Utility Tractor: The primary application.
This tractor was offered with either the C157 gasoline engine or a
diesel variant. The C157 powered the standard 544 (row-crop), 544-F
(wheatland), and 2444 industrial backhoe/loader models in certain
markets. PTO power was rated at 40 kW (54 hp).
International 2544 Industrial Tractor: A heavier-duty industrial version
of the 544, featuring a heavier front axle and hydraulic system for
loader and backhoe work. The C157 in this application was governed to
2,400 rpm.
International 544-F (Farmall 544): The high-clearance, row-crop version
of the 544 used extensively for cultivating row crops such as corn and
soybeans. The C157 provided drawbar power of 34 kW (46 hp).
International Harvester Power Units (U-157): The C157 was sold as a
stationary industrial power unit (designated U-157) for applications
including irrigation pumps, grain augers, generators, and small
sawmills. These units featured a radiator, fuel tank, and control panel
mounted on a skid base.
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