Caterpillar 3412 B

Engine Specifications & Applications Of This Engine

Overview of the Caterpillar 3412B Engine

The Caterpillar 3412B engine is a heavy-duty, 12-cylinder diesel platform designed for extreme torque output and long-term dependability in industrial, marine, and power generation applications. As a continuation of the proven 3412 series, the “B” designation represents significant improvements in cooling, airflow, fuel delivery, and long-life performance compared to earlier versions.

With a displacement of 27 liters, the 3412B engine delivers up to 1,250 horsepower in turbocharged and aftercooled configurations. Known for its fully mechanical fuel system and durable block architecture, the 3412B is still widely used today in repowered vessels, generator sets, offshore equipment, and large industrial machines. Operators favor the 3412B for its rebuildability, mechanical simplicity, and global support from the aftermarket.

Diesel Pro Power is a trusted source for high-quality aftermarket parts for the Caterpillar 3412B, including overhaul kits, gaskets, turbochargers, cylinder heads, oil pumps, water pumps, and more. With a global customer base of over 40,000 satisfied professionals, we support the engines that keep businesses running.

Technical Specifications of the Caterpillar 3412B

Engine Configuration

• Engine Type: 4-stroke V12 diesel

• Displacement: 27.0 liters (1,648 cubic inches)

• Bore x Stroke: 5.4 in x 6.5 in (137 mm x 165 mm)

• Compression Ratio: Typically 14.5:1

• Cylinder Arrangement: 60° V12 configuration

• Aspiration: Turbocharged and aftercooled (ATAAC or JWAC)

• Firing Order: 1R-5R-3R-6R-2R-4R-1L-5L-3L-6L-2L-4L

Performance Ratings

• Horsepower Range: 750 HP to 1,250+ HP depending on tuning and duty cycle

• Torque Output: Up to 3,400 lb-ft or higher at 1,400–1,600 RPM

• Rated RPM: 1,800 to 2,100

• Idle Speed: 600–800 RPM

• Dry Weight: Approximately 5,000–5,300 lbs (varies by setup)

Fuel System

• Fuel Delivery: Mechanical direct injection

• Injection Type: Inline fuel injection pump

• Fuel Type: No. 2 diesel, ULSD-compatible with upgraded sealing

• Governor: Mechanical, with adjustable speed control

• Fuel Filtration: Primary and secondary filter assemblies

Cooling and Lubrication

• Oil Capacity: 14 to 20 gallons depending on oil pan configuration

• Lubrication Type: Gear-driven, full-pressure oil system

• Cooling System: Gear-driven centrifugal water pump

• Coolant Capacity: Approximately 12 to 15 gallons

• Thermostats: Dual thermostats, standard operation 180–200°F

Electrical and Starting System

• Voltage Options: 12V or 24V

• Starter Type: Electric or air-start depending on application

• Charging System: Alternator-driven, 55 to 100 amps

• Controls: Fully mechanical, ECM not required

Key Aftermarket Rebuild and Service Focus

The Caterpillar 3412B is a prime candidate for rebuilds, restorations, and heavy-service repower applications. Diesel Pro Power supplies parts for all critical rebuild zones:

• Overhaul Kits – In-frame and out-of-frame options

• Cylinder Heads – Remanufactured or new for left and right banks

• Turbochargers – Single and twin setups available

• Cooling System – Water pumps, thermostats, radiator components

• Fuel System – Injectors, injection pumps, and return lines

• Gasket Sets – Full engine kits or top-end rebuild gaskets

• Oil System – Pumps, oil coolers, bypass valves, and filters

Each part is quality-tested to meet or exceed OEM specifications for durability and performance.

Applications of the Caterpillar 3412B Engine

The 3412B engine remains a widely used platform across high-load industries, particularly in marine propulsion, stationary power, oilfield equipment, and export market machinery.

Marine Applications

Known for exceptional torque and marine adaptability, the 3412B is widely installed in:

• Tugboats and Push Boats – For continuous duty torque and reliability

• Commercial Fishing Vessels – Deep sea and trawler vessels with twin 3412B configurations

• Crew Boats and Offshore Service Vessels – Propulsion and auxiliary systems

• Work Barges and Landing Craft – Trusted in both civilian and military operations

• Marine Generators – Used as reliable onboard power systems

Diesel Pro Power supports these marine applications with corrosion-resistant components, jacket water-cooled parts, and marine-rated gasket materials.

Power Generation

The high torque and long life of the 3412B make it ideal for both standby and primary power systems:

• Remote Generator Sets – In mining, oil, and construction operations

• Emergency Standby Power – Hospitals, industrial parks, and military installations

• Export Generator Packages – For non-EPA markets where robust mechanical engines are preferred

• Mobile Generator Trailers – For equipment rental, disaster response, or utility work

The 3412B provides frequency stability and load endurance under continuous operation—making it a preferred choice for genset operators worldwide.

Oilfield and Industrial Equipment

The Caterpillar 3412B remains in widespread use in the oilfield and across heavy-duty industrial installations:

• Fracking and Stimulation Units – Drives for high-pressure pumps

• Mud Pumps and Blenders – Rugged diesel power for field operations

• Compressor Packages – For flare gas and pipeline pressurization

• Drilling Rigs and Workover Units – Reliable and field-serviceable diesel drive

• Rock Crushers, Grinders, and Chippers – For mining, logging, and material handling

Diesel Pro Power stocks reinforced gaskets, cooling system parts, and heavy-duty wear components tailored to these applications.

Why the 3412B Remains a Preferred Aftermarket Engine

Even as electronic engines with emissions controls dominate new builds, the 3412B is still actively supported and rebuilt due to:

• Mechanical Simplicity – No ECU, sensors, or electronic diagnostics required

• Serviceability – Wet sleeves, bolt-on heads, and accessible valve train

• Durability – Forged crankshaft and robust turbo configurations

• Rebuild Support – Fully supported in the aftermarket

• High Torque Delivery – Ideal for propulsion, load-handling, and compression

These qualities make the 3412B a prime engine for repower projects and long-term investment.

Diesel Pro Power: The Aftermarket Leader for 3412B Engine Parts

We offer a complete range of Caterpillar 3412B aftermarket parts, including:

• Overhaul kits and piston assemblies

• Cylinder heads and gasket sets

• Turbochargers and aftercooling components

• Oil and water pumps

• Fuel system injectors and pump assemblies

• Replacement sensors, mounts, and filter bases

Our technical team provides diagrams, part identification help, and global shipping to ensure your rebuild or repair is completed quickly and correctly.

Conclusion

The Caterpillar 3412B remains one of the most trusted heavy-duty diesel engines in marine, power, and industrial applications. With a mechanical fuel system, high horsepower, and proven field longevity, it offers unmatched value for fleets and operators who depend on performance and durability.

Diesel Pro Power is committed to keeping these engines running at their best. Whether you're overhauling a marine propulsion system or maintaining a generator in a remote site, we have the parts and expertise you need to keep your 3412B working for years to come.

Additional Resources

Marine CAT 3412 Component Maintenance Life

The Legacy of the Caterpillar Marine 3412 Engine

What Is The Caterpillar 3412 DITA?