International C153 Specifications
| Engine Model: International Harvester C153 |
| Engine Type: 4-stroke in-line 4-cylinder liquid-cooled gasoline |
| Total Displacement: 153 cu.in (2.5 L) |
| Rated Engine Power: 55 Hp (40 kW) at 2200 rpm |
| Fuel System Type: Updraft carburetor |
____________________________________________________________________________________
The International C153 is a 2.5-liter,
naturally aspirated, inline-four gasoline engine produced by
International Harvester (IH) during the 1960s and early 1970s. This
engine served as the primary powerplant for several popular utility and
row-crop tractors, most notably the Farmall 504 and the International
2504 industrial version. It also found applications in various power
units and combines.
The C153 was designed during an era when farm equipment demanded
reliability, serviceability, and a flat torque curve for consistent
operation under variable loads. Its robust construction includes a
replaceable wet-sleeve cylinder design, a feature that allowed
economical overhauls without removing the engine block from the chassis.
The engine produces gross power of 55 hp at 2,200 rpm, with power
take-off (PTO) output rated between 45 and 46 hp depending on the
specific tractor configuration. The C153 is recognized for its lugging
ability at low engine speeds, a direct result of its long-stroke design
measuring 4.250 in (108.0 mm). Many units remain operational today,
supported by a legacy of parts availability through aftermarket
agricultural suppliers.
The International C153 adheres to conventional four-cycle engine
principles with a valve-in-head (OHV) design. The engine is naturally
aspirated and governed by a mechanical flyweight system driven through
the timing gear train. The bore measures 3.375 in (85.7 mm), while the
stroke extends to 4.250 in (108.0 mm), providing an undersquare
configuration that emphasizes torque production at reduced engine
speeds. The compression ratio is 7.5:1, suitable for low-octane fuels
available during the 1960s. The firing order is 1-3-4-2, standard for
American inline-fours.
Gross power output is 55 hp at the flywheel, achieved at a rated speed
of 2,200 rpm in tractor applications. Industrial and power unit versions
permitted operation up to 2,400 rpm. PTO power measures 45-46 hp, with
drawbar power at approximately 40 hp. Maximum torque reaches 135 lb-ft
(183 Nm) between 1,200 and 1,400 rpm. The engine idles smoothly at
450-500 rpm, with a governed no-load maximum speed of 2,425 rpm to
prevent overspeed conditions.
The cylinder block is constructed from cast iron, providing rigid
support for internal components. A distinguishing characteristic of the
C153 block is its replaceable wet-sleeve cylinder liner design. Unlike
dry liners, these sleeves contact the engine coolant directly, enhancing
heat dissipation from the combustion chamber to the cooling system.
Each cylinder liner stands 7.312 in (185.7 mm) tall with a flange at the
top for precise block seating. Liner protrusion above the block deck
must measure 0.002-0.006 in (0.05-0.15 mm) to ensure proper cylinder
head gasket sealing. The block features an oil gallery that runs the
length of the crankcase, drilled to feed the three main bearings,
camshaft bearings, and hydraulic valve lifters.
A side-mounted distributor drive housing bolts to the block at the right
front corner. The engine mounting bosses conform to International
Harvester’s standard dimensions, allowing interchangeability with other
C-series engines including the C135 and C175. The block casting
incorporates a large access cover on the side for cleaning the oil sump
and removing internal components without complete disassembly.
0The cylinder head is a cast iron, single-piece design employing an
overhead valve (OHV) arrangement with pushrods and rocker arms. Valve
configuration is inline, with intake and exhaust valves arranged along a
single axis. The intake valve head diameter measures 1.375 in (34.9 mm),
while the exhaust valve head diameter is 1.218 in (30.9 mm).
Both valves are constructed from silicon-chromium steel for
high-temperature resistance. Valve stem diameter is 0.343 in (8.7 mm).
The valve seats are induction-hardened directly into the head casting
for intake ports, while the exhaust seats receive replaceable inserts
made of heat-resistant alloy. Valve guides are press-fit, with an inside
diameter of 0.344 in (8.74 mm). The valve lash adjustment is performed
with the engine at operating temperature. Intake valve lash is set to
0.014 in (0.36 mm), and exhaust valve lash is also 0.014 in (0.36 mm).
The cylinder head gasket is a composite steel-asbestos design (modern
replacements use fiber composite materials). Eight cylinder head bolts
retain the head to the block. Spark plugs are located on the side of the
cylinder head, angled toward the combustion chamber. The rocker arm
assembly includes a steel shaft supported by four stands, with stamped
steel rocker arms actuated by hollow pushrods.
The fuel system employs an updraft carburetor, mounted below the intake
manifold. International Harvester specified either a Zenith or
Marvel-Schebler carburetor depending on production date and tractor
model. The carburetor’s float-type design draws air upward through a
vertical throat; fuel is metered through a main jet and an idle circuit.
A mechanical flyweight governor, gear-driven from the camshaft, controls
the carburetor throttle plate via a linkage system.
The governor maintains engine speed under varying loads by adjusting the
throttle opening. Governor spring tension is adjustable for fine-tuning
the rated speed setting. Fuel pump type is a mechanical diaphragm pump
mounted to the engine block, driven by an eccentric lobe on the
camshaft. Fuel pump pressure ranges from 3 to 5 psi (21 to 34 kPa).
The intake manifold is a single-plane, cast iron unit feeding all four
cylinders. The carburetor-to-manifold gasket includes a heat shield to
prevent fuel vaporization issues. A dry-type air cleaner with
replaceable paper element is standard on later models, while early units
used an oil-bath air cleaner. The fuel sediment bowl and filter are
mounted between the fuel tank and pump to trap water and debris.
The lubrication system is a fully pressurized, wet-sump design. A
gear-type oil pump, mounted inside the oil pan and driven by the
distributor shaft, draws oil through a screened pick-up tube. Oil
pressure at rated engine speed is maintained between 25 and 40 psi (172
and 276 kPa). The system total capacity, including the oil filter, is
6.0 U.S. qt (5.7 L).
A full-flow spin-on oil filter mounts externally to the block, bypassing
unfiltered oil through a relief valve if the filter becomes restricted.
The oil relief valve, located near the oil pump, opens at 50 psi (345
kPa) to prevent excessive pressure during cold starts. The crankshaft
features drilled oil passages feeding the connecting rod bearings. The
camshaft bearings receive oil through drilled passages from the main oil
gallery.
Hydraulic valve lifters are not used; solid lifters with pushrod
adjustment are standard. Oil pan capacity includes a baffle to prevent
oil starvation during operation on slopes. Recommended oil viscosity is
SAE 30 for ambient temperatures above 32°F (0°C) and SAE 10W or 20W for
colder conditions.
The cooling system is a liquid-cooled design with a belt-driven water
pump. The pump circulates coolant through the cylinder block, around the
wet sleeves, and upward into the cylinder head. Radiator capacity is
13.0 to 14.0 U.S. qt (12.3 to 13.2 L) including the engine block. A
wax-pellet thermostat, rated at 180°F (82°C), controls coolant flow to
the radiator. Cooling system pressure regulation is 7 psi (48 kPa)
maximum through a vented radiator cap. The radiator core is a
tube-and-fin construction.
A four-blade fan is installed on the water pump pulley. The cooling
system incorporates a bypass circuit allowing coolant circulation inside
the engine when the thermostat is closed, preventing hot spots during
warm-up. Freeze plugs are pressed into the cylinder block to protect
against freeze damage. Coolant recommendations in period literature call
for a 50/50 mixture of water and ethylene glycol antifreeze. The water
pump shaft is sealed with a carbon-faced seal; leakage from the weep
hole indicates seal failure.
Ignition System: The ignition system uses a battery-coil,
distributor-based design. The distributor is gear-driven from the
camshaft and rotates counterclockwise. Breaker point gap is set to 0.020
in (0.51 mm), with a dwell angle of 31-34°. Ignition timing at idle (450
rpm) is 3° before top dead center (BTDC). With centrifugal advance,
total timing advances to 25° BTDC by 1,600 rpm. No vacuum advance is
provided. The spark plug gap is 0.025 in (0.64 mm). Recommended spark
plugs are Champion D18Y or equivalent with a heat range suited for light
to medium-load tractor operation. The ignition coil is a conventional
oil-filled type requiring an external ballast resistor for 12-volt
systems.
The electrical system operates at 12 volts with negative ground. A
belt-driven generator, later replaced by an alternator on final
production models, charges the battery through a mechanical voltage
regulator. Starter motor is a 12-volt, direct-drive type engaging the
flywheel ring gear.
Governor System: A mechanical flyweight governor is integral to the
engine timing gear housing. Weights pivot against a thrust bearing,
moving a linkage rod to the carburetor throttle. A hand lever on the
tractor dashboard provides operator speed selection through a spring
tension adjustment. The governor maintains the selected speed within
5-10 rpm under normal load variation.
The complete engine dry weight is 450 lb (204 kg). Overall engine
length, measured from front pulley to flywheel housing mounting face, is
29.5 in (749 mm). Maximum width, across the carburetor and exhaust
manifold, is 18.0 in (457 mm). Height, from oil pan rail to top of the
rocker arm cover, is 26.0 in (660 mm). The crankshaft flange height
(centerline above the oil pan rail) is 7.5 in (191 mm). The flywheel
housing conforms to SAE No. 4 dimensions with a bolt circle of 10.875 in
(276 mm).
Engine oil and oil filter change intervals are recommended every 100
operating hours under normal conditions. Spark plug replacement occurs
every 200 hours. Breaker point inspection and adjustment are performed
every 150 hours. Valve lash is checked every 500 hours. The cooling
system requires draining, flushing, and refilling every 1,000 hours or
24 months.
Air cleaner maintenance intervals depend on operating dust conditions;
the dry element is replaced or the oil-bath cleaned every 50 hours in
field conditions. The wet cylinder sleeves must be measured for wear at
overhaul; service limit for bore wear is 0.005 in (0.13 mm) oversize
before replacement. Piston ring gap, when new, is 0.010-0.020 in
(0.25-0.51 mm) for compression rings and 0.015-0.025 in (0.38-0.64 mm)
for oil rings.
Cylinder Head Bolts: 80-90 lb-ft (108-122 Nm)
Connecting Rod Cap Nuts: 45-50 lb-ft (61-68 Nm)
Main Bearing Cap Bolts: 75-85 lb-ft (102-115 Nm)
Flywheel Bolts: 55-65 lb-ft (75-88 Nm)
Rocker Arm Assembly Bolts: 25-30 lb-ft (34-41 Nm)
Intake Manifold Nuts: 25-30 lb-ft (34-41 Nm)
Exhaust Manifold Nuts: 25-30 lb-ft (34-41 Nm)
Spark Plugs: 20-25 lb-ft (27-34 Nm)
Oil Pan Bolts: 10-12 lb-ft (14-16 Nm)
Water Pump Bolts: 20-25 lb-ft (27-34 Nm)
Timing Gear Cover Bolts: 12-15 lb-ft (16-20 Nm)
Carburetor Flange Nuts: 15-18 lb-ft (20-24 Nm)
Governor Cover Bolts: 10-12 lb-ft (14-16 Nm)
Crankshaft Pulley Bolt: 125-135 lb-ft (169-183 Nm)
The International C153 engine was utilized across several International
Harvester platforms:
1961-1968 Farmall 504 (Row-Crop Tractor): Standard engine for the
gasoline version, offered with either wide or narrow front axle
configurations.
1961-1968 International 504 (Utility Tractor): Lower-profile utility
version used for orchard, industrial, and turf applications.
1965-1972 International 2504 (Industrial Tractor): Industrial variant
with heavier chassis and front loader compatibility.
International UC-153 Power Unit: Stationary power unit for pumps,
generators, and conveyors.
International 124 Hay Baler: Power source for the self-propelled baler
configuration.
International 203 Combine: Smaller combine harvester used on farms with
limited acreage.
____________________________________________________________________________________
| Industrial Engines Technical Specifications |
| Car Engines Technical Specifications |
| Small Engines Technical Specifications |
| Outboard Engines Technical Specifications |
