International C113 Specifications
| Engine Model: International Harvester C113 |
| Engine Type: 4-stroke in-line 4-cylinder liquid-cooled gasoline |
| Total Displacement: 113.1 cu.in (1.85 L) |
| Rated Engine Power: 17-23 Hp (12.5-17 kW) at 1400 rpm |
| Fuel System Type: Updraft carburetor |
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The International C113 is a 1.9-liter,
naturally aspirated inline-four gasoline engine produced by
International Harvester (IH) from the late 1930s through the 1940s. It
is most famous for powering the Farmall A, B, and early C tractors. This
engine is a rugged, overhead-valve (OHV) design that shared many
components with the later, slightly larger C123. Its architecture
prioritized durability and serviceability under extreme agricultural
conditions.
The C113 features a long-stroke configuration and operates at low
rotational speeds to maximize torque delivery for field work. A
distinctive engineering choice was the use of replaceable wet cylinder
sleeves, allowing the engine block to be rebuilt without specialized
boring equipment. The thermo-siphon cooling system on early variants
eliminated the need for a water pump, relying on natural convection for
coolant circulation. This engine established a reputation for
reliability that persisted through decades of hard use.
The International C-113 engine family encompasses several variants
differentiated by governor configurations, magneto versus battery
ignition, and cooling system details. The engine architecture is defined
by its L-head design elimination; instead, it uses a flathead
configuration avoided in favor of an overhead valve layout with pushrods
and rocker arms. The cylinder numbering order is 1-2-3-4, with the
engine rotating clockwise when viewed from the front pulley. The bore
measures 76.2 mm (3.00 in) and the stroke is 101.6 mm (4.00 in),
resulting in a total displacement of 1,853 cc (113.1 cu.in).
The firing order is 1-3-4-2. Compression ratio is 5.33:1, calibrated for
low-octane fuels available during the production era. Rated engine speed
for agricultural versions is 1,400 rpm. Rated power ranges from 17 to 23
hp (12.5-17 kW) depending on specific tractor model and governed rpm.
Drawbar horsepower output is 13 to 15 hp (9.7-11.2 kW). Maximum torque
is 108-122 Nm (80-90 lb-ft), achieved below 1,000 rpm.
The cylinder block is constructed from high-strength cast gray iron,
incorporating an open-deck design above the crankshaft centerline. The
unique feature of the C113 block is the use of replaceable wet cylinder
sleeves, also known as liner barrels. Each cylinder has an independent,
centrifugally cast iron sleeve that contacts the coolant directly on its
outer surface. Lower O-ring seals and an upper flange gasket prevent
coolant leakage into the crankcase.
The block lacks integral cylinder bore surfaces, meaning the parent
casting serves only as a structural carrier and coolant jacket housing.
The deep-skirt design extends below the crankshaft centerline for
increased rigidity. The crankshaft is supported by three main bearings,
a configuration suitable for low-rpm, high-torque operation. The bearing
saddles are machined directly into the block. The camshaft is positioned
in the upper right side of the crankcase, driven by a gear train from
the crankshaft. A removable side cover provides access to the valve
train pushrods and lifters.
The cylinder head is a single, cast iron unit with a flat mating surface
designed to seal against a composite head gasket. The combustion
chambers are fully machined into the head surface, featuring a bathtub
shape that promotes flame travel across the bore. The overhead valve
arrangement uses a cam-in-block design. The camshaft actuates mechanical
flat tappet lifters, which push hollow steel pushrods upward through
channels in the block side.
The pushrods actuate cast iron rocker arms mounted on a steel shaft
bolted to the cylinder head. The valves are arranged in a single row
along the head centerline. Intake valve diameter is 32.0 mm (1.26 in);
exhaust valve diameter is 29.0 mm (1.14 in). Valve stems use a
positive-type seal on the intake side only, as the exhaust stem operates
at higher temperatures. The valvetrain requires no hydraulic lash
adjusters. A stamped steel valve cover seals the top of the head.
The fuel system operates on gravity feed or low-pressure mechanical pump
depending on vehicle application. The primary fuel delivery component is
an updraft carburetor manufactured by either Zenith or IHC. The updraft
configuration draws air upward through the carburetor body, reducing
fuel spillage on slopes. The carburetor incorporates an idle circuit,
main metering circuit, and a power enrichment circuit. A float-type fuel
bowl maintains constant fuel level.
The fuel inlet uses a needle and seat assembly. Choke and throttle
plates are manually controlled from the operator station. A mechanical
flyweight governor, gear-driven from the camshaft, modulates the
throttle plate position to maintain engine speed under varying load. The
governor uses a thrust bearing and linkage system to override the hand
throttle. Fuel delivery from the tank uses a sediment bowl with a
replaceable screen filter. No fuel return line to the tank is present.
The lubrication system is a splash-and-pressure combination design. A
gear-type oil pump, driven by a worm gear on the camshaft, draws oil
from a stamped steel oil pan through a screen-covered intake pipe. The
pump delivers pressurized oil to a single main gallery machined into the
right side of the cylinder block. This gallery supplies the three main
bearings and the camshaft bearings. The connecting rod bearings receive
oil through drilled passages from the crankshaft journals.
The cylinder walls, piston pins, and camshaft lobes receive oil from
splash generated by connecting rod dippers and crankshaft
counterweights. The oil pump incorporates a pressure relief valve set to
2.8-3.4 bar (40-50 psi). A partial-flow oil filter mounts externally,
receiving a small portion of the pump output and returning filtered oil
directly to the oil pan. Total system capacity, including filter, is
3.8-4.7 L (4.0-5.0 qt). Recommended oil viscosity is SAE 30 for most
ambient temperatures.
The cooling system configuration varies between early and late
production engines. Early C-113 engines utilize a thermo-siphon system
with no water pump. Coolant circulates solely by convection: heated
coolant rises from the cylinder head into the top radiator tank, cools
as it passes through the radiator core, and sinks back to the lower
radiator hose entering the cylinder block. This system requires a large
radiator volume and unobstructed vertical passages.
Later versions add a belt-driven centrifugal water pump mounted to the
front of the cylinder block. The pump circulates coolant through the
block, cylinder head, radiator, and a heater core if equipped. A
wax-pellet thermostat located in the upper radiator hose housing
regulates operating temperature between 71-82°C (160-180°F). The cooling
system uses a non-pressurized radiator cap on early units, transitioning
to a 0.3 bar (4 psi) pressure cap on later pump-equipped versions. Total
coolant capacity is 12.3 L (13.0 qt).
| Exhaust and Governor Systems |
Exhaust System: A cast iron exhaust manifold with two ports (cylinders
1-2 and 3-4 combined) routes gases to a vertical muffler. The manifold
incorporates a heat riser valve that directs exhaust flow under the
intake manifold during warm-up to aid fuel vaporization.
Governor System: The mechanical flyweight governor mounts inside the
timing gear cover. Weights pivot outward against spring tension as
engine speed increases, moving a thrust washer and linkage that
progressively closes the carburetor throttle plate. The system maintains
set speed within 50 rpm under load variations.
| Ignition and Electrical System |
Ignition System: Two configurations exist. Magneto ignition uses a
gear-driven magneto mounted on the front timing cover, producing its own
power without a battery. A breaker point assembly inside the magneto
opens at 0.51 mm (0.020 in) gap. Battery ignition uses a 6-volt
distributor with a coil and external ballast resistor. The breaker point
gap is identical at 0.51 mm (0.020 in). Spark plug gap is 0.64 mm (0.025
in). Spark plug heat range is specified as Champion D16 or equivalent.
Ignition timing is manually adjustable by rotating the magneto or
distributor housing.
Electrical System: Original equipment uses a 6-volt system with positive
ground. The charging system consists of a belt-driven generator rated at
15-20 amps. A voltage regulator includes cutout relay, current limiter,
and voltage control functions. The starting system uses a 6-volt starter
motor engaging a ring gear on the flywheel.
Overall length from the front pulley to the flywheel housing mounting
face is 760 mm (30.0 in). Width across the cylinder block, including the
side cover and distributor, is 510 mm (20.0 in). Height from the oil pan
rail to the top of the valve cover is 660 mm (26.0 in). The dry weight
of the complete engine, including the flywheel, carburetor, manifold,
and starter but without coolant or oil, is 227 kg (500 lb). The
crankshaft centerline height from the oil pan rail is 120 mm (4.75 in).
The engine mounting centers are spaced 560 mm (22.0 in) apart
longitudinally.
Valve clearance adjustment is required every 300 operating hours. Hot
valve clearances (engine at operating temperature) are 0.36 mm (0.014
in) for both intake and exhaust valves. Cold clearance is set 0.05 mm
(0.002 in) tighter. The oil and filter change interval is 100 operating
hours under normal conditions. The crankcase breather, a mesh-type oil
bath unit, requires cleaning every 100 hours. The spark plug replacement
interval is 300 operating hours.
The breaker point replacement interval is 500 operating hours for
battery ignition, 300 hours for magneto. The governor linkage requires
lubrication at the pivot points every 200 hours using light engine oil.
The cooling system requires flushing every 600 operating hours. The wet
cylinder sleeve O-rings do not have a scheduled replacement interval but
require replacement whenever sleeves are removed. The timing gear train
requires no routine maintenance as it operates in an oil bath.
Cylinder Head Nuts: 108-115 Nm (80-85 lb-ft).
Connecting Rod Nuts: 61-68 Nm (45-50 lb-ft).
Main Bearing Cap Bolts: 102-108 Nm (75-80 lb-ft).
Flywheel Housing Bolts: 54-61 Nm (40-45 lb-ft).
Flywheel Bolts: 81-88 Nm (60-65 lb-ft).
Rocker Arm Shaft Bracket Bolts: 34-41 Nm (25-30 lb-ft).
Intake Manifold Nuts: 34-41 Nm (25-30 lb-ft).
Exhaust Manifold Nuts: 34-41 Nm (25-30 lb-ft).
Valve Cover Bolts: 7-9 Nm (5-7 lb-ft).
Oil Pan Bolts: 14-20 Nm (10-15 lb-ft).
Spark Plugs: 27-34 Nm (20-25 lb-ft).
Governor Cover Bolts: 14-20 Nm (10-15 lb-ft).
Carburetor Mounting Nuts: 20-27 Nm (15-20 lb-ft).
The International C113 engine was utilized across a range of
agricultural and industrial equipment from approximately 1939 to 1953.
Farmall A: Tractor (1939-1947). Rated at 16 belt hp at 1,400 rpm.
Farmall B: Tractor (1939-1947). Same rating as Farmall A with narrower
rear track.
Farmall BN: Tractor (1940-1947). Narrow version of the B model.
Farmall C: Early production (1948-1951) before transitioning to the C123
engine.
International I-40: Industrial power unit version used for pumps and
generators.
International W-40: Power unit variant with heavier flywheel for belt
work.
McCormick-Deering O-4: Orchard version with enclosed components and
spark-arresting exhaust.
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