Cat 3406C Specifications
| Engine Model: Caterpillar 3406C |
| Engine Type: 4-cycle inline 6-cylinder turbocharged and aftercooled diesel |
| Total Displacement: 893 cu.in (14.6 L) |
| Rated Engine Power: 375-465 Hp (280-347 kW) at 2000 rpm |
| Fuel System Type: Electronic unit injector (EUI) |
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The Caterpillar 3406C is an inline
six-cylinder, 14.6-liter heavy-duty diesel engine representing a refined
and electronically controlled evolution of the 3406B platform. This
engine was engineered to deliver increased power, improved fuel
efficiency, and enhanced emissions compliance for the late 1990s market.
As a key member of the "C-Series" within the 3400 family, it integrated
full electronic unit injection and advanced digital controls while
retaining the legendary mechanical durability of its predecessors.
The 3406C is characterized by its robust deep-skirt block, cross-bolted
main bearings, and the Caterpillar ADEC (Advanced Digital Electronic
Control) management system. Designed for maximum uptime in demanding
on-highway, industrial, and marine applications, it offers a balance of
sophisticated electronic diagnostics and the inherent strength that
established the 3406's reputation for million-mile durability.
Engine Type: Inline 6-Cylinder, Four-Stroke Cycle Diesel.
Aspiration: Turbocharged and Air-to-Air Aftercooled (ATAAC).
Displacement: 14.6 Liters (893 cubic inches).
Bore: 137 mm (5.4 inches).
Stroke: 165 mm (6.5 inches).
Engine Power: 375 hp (280 kW) - 465 hp (347 kW) at 1800-2100 rpm.
Compression Ratio: 14.5:1.
Firing Order: 1-5-3-6-2-4.
Rotation (Viewed from Flywheel End): Counterclockwise.
Governor Type: Electronic, managed by the Advanced Digital Electronic
Control (ADEC) system.
Emission Certification: Certified to U.S. EPA 1998 heavy-duty on-highway
emissions standards.
The cylinder block is a massive, deep-skirt cast iron structure
providing a rigid foundation for high cylinder pressures. It
incorporates replaceable wet-type cylinder liners. The liners are
pressed into the block and sealed at the top with a copper composition
gasket under a precision-machined flange.
The lower end employs a cross-bolted main bearing design of exceptional
strength. Each of the seven nodular iron main bearing caps is secured by
two vertical bolts and two horizontal cross bolts that thread into the
block's lower skirt. This configuration ensures maximum crankshaft
support and alignment. The camshaft is gear-driven and rotates within
bearings machined directly into the block material.
A single cast iron cylinder head is used, secured by four bolts per
cylinder. The head employs a four-valve-per-cylinder design - two intake
and two exhaust - to optimize airflow and combustion efficiency. Valve
seat inserts are hardened for extended durability. Valve guides are
replaceable.
The valve train incorporates hydraulic lash adjusters, positioned in the
cylinder head, which act on roller-type rocker arms. This system
eliminates the requirement for scheduled manual valve lash adjustment.
The cylinder head gasket is a multi-layer steel (MLS) design, engineered
to seal the high combustion pressures of the electronically controlled
fuel system.
The 3406C is equipped with Caterpillar's Electronically Controlled Unit
Injector (EUI) system. Each cylinder features a self-contained unit
injector where the engine's camshaft provides the mechanical actuation
force for the injector plunger. The Advanced Digital Electronic Control
(ADEC) module precisely governs the timing and duration of fuel
injection by energizing the injector solenoid.
This system generates injection pressures exceeding 28,000 psi (1930
bar). A gear-type transfer pump supplies fuel from the tank, circulating
it through a primary filter/water separator and a secondary filter
before delivery to the injectors. The electronic control allows for
precise fuel mapping and adaptive timing.
Lubrication is provided by a high-capacity gear-type oil pump driven
from the front gear train. Oil is drawn from a deep, cast aluminum sump
through a pickup tube and screen. It is then forced through a full-flow,
spin-on oil filter. A bypass valve protects the system. Filtered oil is
directed through an integral oil cooler before entering the main oil
gallery.
From the gallery, oil is distributed to the crankshaft main and
connecting rod bearings, camshaft bearings, turbocharger, and valve
train. Piston cooling jets spray a continuous, directed stream of oil
onto the underside of each piston. The system is designed to maintain
stable pressure and provide critical cooling under maximum load.
Coolant circulation is managed by a gear-driven centrifugal water pump.
Coolant flows from the pump through passages in the cylinder block and
cylinder head. Engine operating temperature is regulated by a wax-pellet
thermostat.
The system uses an air-to-air aftercooler (ATAAC) core to cool the
turbocharged intake air, significantly increasing charge density. The
engine cooling system requires a radiator or heat exchanger of
substantial capacity. A coolant conditioner/filter is standard equipment
to maintain proper levels of supplemental coolant additive (SCA) or
Extended Life Coolant (ELC) inhibitors.
Starting System: 12-volt, 24-volt, or 32-volt electric starting motor.
Air starting remained an option for industrial and marine applications.
Charging System: A heavy-duty brushless alternator, commonly rated
between 130 and 160 amperes.
Air Intake System: A dry-type, two-stage air cleaner system with a
primary safety element and a main filter, equipped with an air
restriction indicator. Exhaust System: A tuned, divided-entry cast iron
exhaust manifold optimizes turbocharger response. An electronically
controlled wastegate regulates boost pressure based on ECM commands.
Electronic Control: Governed by the Advanced Digital Electronic Control
(ADEC) module. This system provides comprehensive engine management,
diagnostics, and programmable parameters via the SAE J1708/J1587 data
link. It features enhanced software for fuel economy and performance
over earlier electronic models.
Dimensions are for a core industrial engine configuration. Approximate
length is 1660 mm (65.4 inches), width is 906 mm (35.7 inches), and
height is 1335 mm (52.6 inches). These measurements can vary for
on-highway truck configurations with different front accessory drives
and flywheel housings. The net dry engine weight, excluding fluids but
including standard accessories like alternator and starter, is
approximately 1300 kg (2866 pounds). This weight reflects the engine's
heavy-duty construction and robust internal components.
Engine Oil Grade: Use engine oil meeting Caterpillar’s ECF-1-a
specification, equivalent to API CH-4. For optimal performance and
extended drain capability, API CI-4 oil is recommended. SAE 15W-40 is
standard for general operation.
Oil Change Interval: Extended drain intervals are supported by
electronic monitoring. For on-highway trucks, intervals up to 50,000
miles (80,000 km) were achievable with specified oil and filters.
Severe-service applications follow hourly guidelines, often 500 hours.
Oil analysis is strongly recommended. Oil System Capacity: Total refill
capacity, including a filter change, is 41.6 Liters (11.0 US gallons).
Cooling System Capacity: Total cooling system capacity, including
radiator and aftercooler circuit, is approximately 68.1 Liters (18.0 US
gallons). Fuel Filter: Replace primary and secondary fuel filter
elements at scheduled service intervals, commonly every 30,000 miles
(48,000 km) or 500 hours. Air Filter: Service or replace based on
restriction gauge indication. The primary safety element is serviceable.
Valve Lash Adjustment: The hydraulic lash adjuster system requires no
scheduled mechanical adjustment. Engine Coolant: Use Caterpillar
Extended Life Coolant (ELC) for maximum service intervals and corrosion
protection. If using conventional coolant, maintain a 50/50 ethylene
glycol mix with proper Supplemental Coolant Additive (SCA)
concentration.
Cylinder Head Bolts: Tighten in a specific three-step sequence. Final
torque: 300 Nm (221 lb-ft), followed by a 90-degree angular turn.
Main Bearing Cap Bolts (Vertical): 340 Nm (250 lb-ft) plus an additional
90-degree turn.
Main Bearing Cap Cross Bolts: 190 Nm (140 lb-ft).
Connecting Rod Cap Bolts: 190 Nm (140 lb-ft) plus an additional
90-degree turn.
Flywheel Housing-to-Block Bolts: 190 Nm (140 lb-ft).
Flywheel-to-Crankshaft Bolts: 285 Nm (210 lb-ft).
Unit Injector Clamp Bolt: 35 Nm (26 lb-ft).
Oil Pan Bolts: 55 Nm (41 lb-ft).
Oil Filter Cartridge: Hand-tighten until the gasket contacts the base,
then tighten an additional three-quarters turn.
The Caterpillar 3406C engine served in
high-performance roles during its production era:
On-Highway Trucks: Found in late-model heavy-duty trucks from Kenworth
(T2000, W900L), Peterbilt (379, 387), Freightliner (Columbia, Century
Class), and Navistar International (9000i series) as a premium
electronic powertrain option. Construction/Mining: Powered Caterpillar
775D, 777C Quarry Trucks; 992D Wheel Loaders; and large hydraulic mining
shovels. Marine Propulsion: Used in commercial fishing vessels,
tugboats, patrol boats, and high-performance yachts, with
continuous-duty ratings meeting demanding marine standards.
Power Generation: Employed as a prime mover for large continuous-duty
generator sets in the 400-800 kVA range. Industrial: Powered large
hydraulic power units, high-pressure pumps, and oilfield service
equipment such as frac pumps. Specialty Vehicles: Continued to power
heavy-duty fire apparatus, severe-service vocational trucks, and
specialized haulage equipment.
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