Cat C3.6 Specifications
| Engine Model: Caterpillar C3.6 |
| Engine Type: 4-stroke in-line 4-cylinder turbocharged liquid-cooled diesel |
| Total Displacement: 220 cu.in (3.6 L) |
| Rated Engine Power: 74-134 Hp (55-100 kW) at 2300 rpm |
| Fuel System Type: Common rail direct injection |
____________________________________________________________________________________
0The Caterpillar C3.6 is a 3.6-liter,
4-cylinder, in-line diesel engine that represents a significant
advancement in Cat’s compact power lineup. Designed as a direct
replacement for the 4.4-liter engine in many applications, it achieves
superior power density through modern engineering. The C3.6 is built for
the rigorous demands of compact construction equipment, including
backhoe loaders, compact wheel loaders, and small excavators.
Its foundation is a robust, all-cast iron design, incorporating a
high-pressure common rail fuel system and a sophisticated emissions
aftertreatment solution. The engine is noted for its exceptional torque
rise, quiet operation, and optimized fuel consumption, meeting stringent
global emission standards without sacrificing the reliability and
durability expected from Caterpillar. By consolidating power into a
smaller displacement package, the C3.6 allows manufacturers to reduce
machine size while maintaining or improving performance.
Engine Type: 4-cycle, In-line, 4-cylinder diesel.
Displacement: 3.6 Liters (220 cu.in).
Bore: 98.0 mm (3.8 in).
Stroke: 120.0 mm (4.7 in).
Combustion System: Direct Injection.
Compression Ratio: 17.0:1.
Rotation: Counterclockwise (facing flywheel).
Rated Power: 55 kW to 100 kW (74 HP to 134 HP).
Rated Speed: 2200-2400 RPM.
Maximum Torque: 530 Nm (391 lb-ft) @ 1500 RPM.
Aspiration: Turbocharged and Aftercooled (TA). The system utilizes a
wastegated turbocharger to optimize air delivery across the speed range,
paired with an air-to-air aftercooler (ATAAC) to reduce intake air
temperature, increasing density for improved combustion efficiency.
The cylinder block is constructed from high-grade cast iron, forming a
rigid, deep-skirt design that minimizes bore distortion and vibration.
This construction is essential for maintaining long-term durability
under the high cylinder pressures associated with direct injection and
turbocharging. The block is a parent bore design, meaning the cylinders
are machined directly into the block without liners. This design
enhances structural rigidity and heat transfer while simplifying the
manufacturing process.
The deep skirt extends below the crankshaft centerline, providing robust
support for the main bearing caps, which are of a cross-bolted design in
higher-stress configurations. This ensures crankshaft stability and
longevity under high torque loads. Integrated within the block are
cast-in oil galleries for efficient lubrication and a water jacket
designed for uniform cooling around each cylinder to prevent hot spots
and maintain thermal stability.
The cylinder head is a single, high-strength cast iron unit designed to
accommodate four valves per cylinder - two intake and two exhaust. The
four-valve configuration optimizes airflow, improving volumetric
efficiency and enabling a centrally located fuel injector for optimal
fuel spray pattern distribution within the combustion bowl. The valve
train operates via an overhead camshaft (OHC) design, which reduces
reciprocating mass and increases valvetrain stiffness for precise valve
timing at all engine speeds.
The camshaft is driven by a gear train from the crankshaft, ensuring
long-term timing accuracy without the maintenance requirements of a
belt. Valve seats and guides are manufactured from wear-resistant
materials to withstand the high thermal and mechanical loads of
turbocharged operation. The cylinder head gasket is a multi-layer steel
(MLS) design, selected for its superior sealing capability under high
cylinder pressures, preventing gas, oil, and coolant leaks.
The fuel system is a High-pressure Common Rail (HPCR) system with full
electronic control. This system operates independently of engine speed
and load, generating fuel pressures up to 1800 bar (26,106 psi) to
achieve precise atomization. A high-pressure fuel pump delivers fuel to
a common rail (accumulator) mounted on the cylinder head. From there,
electronic fuel injectors, controlled by the Engine Control Module
(ECM), deliver precisely metered fuel pulses up to five times per
combustion cycle.
This multi-injection capability allows for pilot, main, and post
injections that shape the combustion event. The system facilitates
reduced combustion noise, lower particulate emissions, and optimized
fuel economy. A fuel cooler and a water separator with a built-in primer
pump are integrated into the system to maintain fuel quality and
reliability in diverse operating conditions.
The lubrication system is a forced-feed, full-flow filtration design. A
high-efficiency, gear-type oil pump, driven directly from the crankshaft
gear train, ensures consistent oil flow across the engine speed range.
The system capacity, including the oil filter, is engineered to support
extended service intervals under standard duty cycles. Engine oil is
circulated through a full-flow spin-on filter that captures
contaminants, and a bypass filtration loop ensures continuous cleaning
of the oil.
A piston cooling jet system is integrated into the block, directing
streams of oil to the underside of the piston crowns. This feature is
critical for managing the high thermal loads generated by the
turbocharged, high-pressure combustion process. The oil pan is
constructed from stamped steel and is designed to maintain adequate oil
supply during machine operation on uneven terrain.
Oil Capacity (including filter): 8.0 to 11.0 Liters (8.5-11.6 U.S.
Quarts).
Oil Change Interval: 500 hours, under recommended operating conditions
using Cat oil and filters.
The cooling system is a pressurized, thermostatically controlled circuit
designed to maintain optimal engine operating temperature. A centrifugal
water pump, mounted to the engine front housing, circulates coolant
through the cylinder block, cylinder head, and the aftercooler circuit.
The system utilizes a gear-driven water pump for reliability and a
remote-mounted, wax-type thermostat that provides rapid warm-up to
reduce cylinder bore wear and improve combustion efficiency during cold
starts.
Coolant flows through the cylinder block first to cool the lower
cylinder area, then through the cylinder head to manage the intense heat
of combustion. The cooling system is designed for a high heat rejection
capacity to accommodate the demands of the turbocharger and aftercooler,
ensuring consistent performance in high ambient temperature
environments. Coolant Capacity: 6.0 Liters (1.6 U.S. Gal) for the engine
only. Total system capacity varies with radiator and machine
configuration.
Electrical System: Available in 12-volt or 24-volt options. The system
includes a high-output alternator and a heavy-duty electric starter
motor designed for consistent cold-cranking performance. Full electronic
integration with the machine’s CAN bus system allows for remote
monitoring and diagnostics.
Emissions Technology: The C3.6 achieves global emissions compliance
through a combination of in-cylinder combustion optimization and
aftertreatment. The standard aftertreatment system consists of a Diesel
Oxidation Catalyst (DOC) and a Diesel Particulate Filter (DPF). For
higher horsepower ratings (above 74 HP / 55 kW) to meet Tier 4 Final /
Stage V standards, the system also utilizes Selective Catalytic
Reduction (SCR) requiring Diesel Exhaust Fluid (DEF). The ECM manages
the active regeneration process for the DPF, injecting fuel during the
exhaust stroke to raise exhaust temperatures and burn off accumulated
soot with minimal operator intervention.
Air Intake System: A dual-stage air filtration system is standard,
comprising a primary filter with a high-capacity dust ejector and a
secondary safety filter to protect the engine in the event of a primary
filter breach. The turbocharger is wastegated to prevent over-boost
conditions at high altitudes and to manage peak cylinder pressure.
Weight (Dry): 381 kg (840 lbs). This is the base engine weight without
alternator, starter, aftertreatment, or fluids.
Length: 667 mm (26.3 in). Measured from the front accessory drive to the
flywheel housing mounting face.
Width: 564 mm (22.2 in). Measured at the widest point, typically the
exhaust manifold or fuel pump location.
Height: 787 mm (31.0 in). Measured from the bottom of the oil pan to the
top of the valve cover.
Valve Lash (Cold): Intake: 0.25 mm (0.010 in); Exhaust: 0.50 mm (0.020
in). Valve lash is set using a two-turn method on the adjusting screw
locknut. Oil Change Interval: 500 hours with Cat DEO-ULS (Diesel Engine
Oil - Ultra Low Sulfur) or equivalent. Intervals may be reduced to 250
hours for severe duty cycles, defined as high load factor, high ambient
temperatures, or poor fuel quality.
Fuel Filter: Primary (water separator) and secondary (spin-on) filters.
Replacement interval is 500 hours or as indicated by the restriction
gauge. Coolant Maintenance: Extended life coolant (ELC) with a service
interval of 6000 hours or 6 years. SCA (Supplemental Coolant Additive)
filters are not required with ELC.
Crankcase Ventilation: Equipped with a closed crankcase ventilation
(CCV) system. The CCV filter element requires replacement at 2000-hour
intervals to maintain crankcase pressure control and prevent oil mist
emission. Injection Timing: Non-adjustable. Injection timing is
electronically controlled by the ECM based on input from the crankshaft
and camshaft position sensors.
Connecting Rod Cap: 70 Nm (52 lb-ft).
Main Bearing Cap: 50 Nm (37 lb-ft).
Cylinder Head M12 Bolts: 60 Nm (44 lb-ft).
Cylinder Head M10 Bolts: 35 Nm (26 lb-ft).
Cylinder Head M10 Bolts: 35 Nm (26 lb-ft).
Flywheel Bolts: 130 Nm (96 lb-ft).
Flywheel Housing M10 Bolts: 70 Nm (52 lb-ft).
Flywheel Housing M12 Bolts: 120 Nm (89 lb-ft).
Valve Cover Bolts: 18 Nm (13 lb-ft).
Injector Clamp Bolt: 20 Nm (15 lb-ft).
Backhoe Loaders: Cat 416, 420, 428, and 430 (F2 and Next Gen series).
The engine provides the high torque rise required for simultaneous
digging and travel operations.
Excavators: Cat 312 and 313 models. In these applications, the C3.6 is
configured to meet stringent emission standards while delivering the
hydraulic flow necessary for heavy-duty excavation.
Loaders: Cat 908, 910, and 914 Compact Wheel Loaders. The engine’s
compact dimensions allow for optimized machine design, providing
excellent visibility and maneuverability.
Telehandlers: Various Cat TH series models, including the TH255, TH337,
and TH357. The C3.6 delivers the low-end torque and hydraulic
responsiveness required for precise load placement and lifting
operations.
Industrial Applications: The engine is also utilized in agricultural
tractors, industrial forklifts, and generator sets (as a C3.6 genset
engine) where a compact, emissions-compliant power unit with high power
density is required.
____________________________________________________________________________________
| Industrial Engines Technical Specifications |
| Car Engines Technical Specifications |
| Small Engines Technical Specifications |
| Outboard Engines Technical Specifications |
