Cat 3208T Specifications
| Engine Model: Caterpillar 3208T |
| Engine Type: 4-cycle 8-cylinder turbocharged liquid-cooled diesel |
| Total Displacement: 636 cu.in (10.4 L) |
| Rated Engine Power: 250-375 Hp (186-280 kW) at 2200 rpm |
| Fuel System Type: Direct fuel injection |
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The Caterpillar 3208T is a turbocharged V-8,
10.4-liter diesel engine that represents the high-performance variant of
the widely utilized 3208 platform. By adding a single turbocharger to
the naturally aspirated design, this engine achieves a substantial
increase in power and torque output while maintaining the compact
footprint and mechanical simplicity of the base model. The 3208T is
engineered for applications demanding greater power density without a
corresponding increase in physical size.
It retains the foundational architecture of a 90-degree V-block, wet
cylinder liners, and a mechanically governed fuel system, ensuring
compatibility with established service practices. This engine found its
primary role in marine propulsion and medium-duty trucks where its
enhanced output provided improved performance, making it a favored
choice for workboats and heavier vocational vehicles.
Engine Type: 90-Degree V-8, Four-Stroke Cycle Diesel.
Aspiration: Turbocharged.
Displacement: 10.4 Liters (636 cubic inches).
Bore: 114.3 mm (4.5 inches).
Stroke: 127.0 mm (5.0 inches).
Engine Power (Industrial/Truck): 250-375 HP (186-280 kW).
Engine Power (Marine): 300-435 hp (224-324 kW).
Compression Ratio: 16.0:1 (varies slightly by specific model and
application).
Firing Order: 1-2-7-8-4-5-6-3.
Rotation (Viewed from Flywheel End): Counterclockwise.
Governor Type: Mechanical, variable speed or all-speed.
Emission Certification: Pre-Tier/Stage I mechanical engine.
The cylinder block is the compact, 90-degree V-style cast iron structure
common to the 3208 series. It incorporates replaceable wet-type cylinder
liners for all eight cylinders. The liners are pressed into the block
and sealed at the top with a copper gasket under a precision-machined
flange. This design facilitates overhauls without specialized machining.
The block's 90-degree layout permits the use of a short, rigid
crankshaft with a favorable firing order for smooth operation. Main
bearing caps are nodular iron, each secured by two bolts. The camshaft
is centrally mounted in the "V" and is gear-driven from the crankshaft.
Two separate cast iron cylinder heads are used, one for each cylinder
bank. Each head employs a two-valve-per-cylinder design - one intake and
one exhaust. Valve seat inserts are hardened to withstand the increased
thermal and mechanical loads imposed by turbocharging. Valve guides are
pressed into the head and are replaceable.
Valve actuation is via pushrods and rocker arms, with the rocker arms
shaft-mounted on each cylinder head. Valve lash requires manual
adjustment using a screw and locknut on each rocker arm. The cylinder
head gaskets are composite designs. Each head is secured by ten bolts.
The fuel system is a direct injection, mechanically controlled design.
It utilizes a single, camshaft-driven rotary distributor-type injection
pump (such as a Bosch model) to meter and time fuel delivery. This pump
distributes high-pressure fuel sequentially to individual multi-hole
injectors in each cylinder via dedicated steel fuel lines.
Injection timing is field-adjustable. A mechanical diaphragm-type lift
pump supplies fuel from the tank to the injection pump. The fuel circuit
includes a primary sediment bowl/water separator and a secondary spin-on
fuel filter. The system is entirely mechanical, offering reliability and
straightforward diagnostics.
Lubrication is provided by a gear-type oil pump driven from the
crankshaft gear train. Oil is drawn from the sump through a pickup tube
and screen, then forced through a full-flow, spin-on oil filter. A
pressure relief valve protects the system.
Filtered oil is directed to the main oil gallery and subsequently
supplied to the crankshaft main and connecting rod bearings, the
camshaft bearings, the turbocharger center housing, and the valve gear
via hollow pushrods. The system incorporates an oil cooler to manage the
increased thermal load from turbocharging. Stable oil pressure and
volume are maintained across the operating range.
Coolant circulation is managed by a single, gear-driven centrifugal
water pump located at the front of the engine in the "V". The pump feeds
coolant into two separate passages, one for each cylinder bank. Coolant
flows through block and head passages. A wax-pellet thermostat regulates
engine operating temperature.
The turbocharged 3208T generates more heat than its naturally aspirated
counterpart, necessitating a radiator or heat exchanger of adequate
capacity. Marine applications universally employ a heat exchanger for
closed-circuit cooling. The system is designed for efficient heat
dissipation under sustained high-load operation.
Starting System: 12-volt or 24-volt electric starting motor. Charging
System: A brushless alternator, commonly rated between 65 and 105
amperes, driven by a V-belt from the crankshaft pulley.
Air Intake System: A dry-type air cleaner feeds into the turbocharger
compressor inlet. The turbocharger is mounted centrally, often on the
left side of the engine. Compressed air is routed through a charge air
cooler (aftercooler) on some high-output models before entering the
intake manifold located in the valley. Exhaust System: Exhaust gases
from both cylinder banks are collected by separate cast iron manifolds
and directed into a single inlet on the turbocharger's turbine housing.
Dimensions are consistent with the 3208 platform, with the turbocharger
and associated piping adding minimal increase. For an industrial or
truck configuration, approximate length is 1143 mm (45.0 inches), width
is 876 mm (34.5 inches), and height is 1054 mm (41.5 inches). The net
dry engine weight, without fluids but including standard accessories,
ranges from 722 kg to 772 kg (1592 lb to 1702 lb). The upper end of the
weight range includes engines equipped with a standard oil cooler and
other heavy-duty components associated with higher horsepower ratings.
Engine Oil Grade: Use Caterpillar Diesel Engine Oil (DEO) or an
equivalent oil meeting API CD, CE, or CF-4 classifications. SAE 15W-40
is standard. The turbocharger's high operating speeds make consistent
oil quality and change intervals critical.
Oil Change Interval: Dictated by service severity. Under normal
conditions, intervals of 250 hours are standard. Severe-duty cycles,
especially in dusty environments or with frequent high-load operation,
require more frequent changes, potentially at 150-hour intervals.
Oil System Capacity: Total refill capacity, including a filter change,
is 17.0 Liters (4.5 US gallons). Cooling System Capacity: Total cooling
system capacity varies with installation. For a marine heat exchanger
system, capacity is approximately 34.0 Liters (9.0 US gallons).
Fuel Filter: Replace the secondary fuel filter element every 250 hours.
The primary sediment bowl must be drained of water regularly. Air
Filter: Service or replace the element based on the restriction
indicator. Turbocharged engines are sensitive to intake restriction,
making filter maintenance imperative. Valve Lash Adjustment (Cold):
Intake: 0.38 mm (0.015 in). Exhaust: 0.76 mm (0.030 in). Adjust at
initial break-in and every subsequent 1000 hours of operation.
Engine Coolant: Use a 50/50 mixture of ethylene glycol antifreeze and
demineralized water. Maintain proper concentration of supplemental
coolant additive (SCA) to protect against liner cavitation and
corrosion, which can be exacerbated by higher cylinder pressures.
Cylinder Head Bolts: Tighten in a specific three-step sequence. Final
torque: 190 Nm (140 lb-ft).
Main Bearing Cap Bolts: Tighten to 160 Nm (118 lb-ft).
Connecting Rod Cap Bolts: Tighten to 125 Nm (92 lb-ft), then tighten an
additional 60 degrees.
Flywheel Housing-to-Block Bolts: Tighten to 75 Nm (55 lb-ft).
Flywheel-to-Crankshaft Bolts: Tighten to 160 Nm (118 lb-ft).
Injector Clamp Bolt: Tighten to 35 Nm (26 lb-ft).
Oil Pan Bolts: Tighten to 41 Nm (30 lb-ft).
Oil Filter Cartridge: Hand-tighten until the gasket contacts the base,
then tighten an additional three-quarters turn. Turbocharger Mounting
Nuts/Studs: Tighten to 41 Nm (30 lb-ft).
The Caterpillar 3208T engine was applied in
performance-oriented roles:
Marine Propulsion: The dominant application, powering a vast number of
pleasure craft, sport fishing boats, commercial fishing vessels, patrol
boats, and small ferries where its compact V-8 turbocharged package
offered an excellent balance of power and size. Medium-Duty Trucks: Used
in heavier vocational trucks from Ford, International, and GMC for
applications such as dump trucks, refuse haulers, and larger delivery
trucks requiring more power than the naturally aspirated 3208 provided.
Construction Equipment: Found in heavier models of Caterpillar wheel
loaders (e.g., 950, 966), and certain excavators where increased power
was necessary for demanding cycles. Industrial: Powered larger generator
sets (75-150 kVA), fire pump packages, and high-capacity air
compressors. Specialty Vehicles: Used in fire apparatus, rescue trucks,
and airport ground support equipment where a compact, high-output diesel
was advantageous.
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