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Detroit Diesel 12V71 Turbo – Engine Specifications & Applications

 

Engine Specifications for the Detroit Diesel 12V71 Turbo

Configuration and Basic Architecture

  • Engine Type: Two-stroke, V-type 12-cylinder diesel engine

  • Configuration: 12V71 (12 cylinders in a 60° V configuration)

  • Displacement: 852 cubic inches (13.96 liters)

  • Bore x Stroke: 4.25 in x 5.00 in (108 mm x 127 mm)

  • Aspiration: Turbocharged (with or without intercooler depending on application)

  • Fuel System: Unit injectors per cylinder (mechanically actuated)

  • Cycle: Two-stroke diesel cycle

  • Compression Ratio: Approximately 17:1

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

  • Cooling System: Water-cooled block, with fresh water and seawater options in marine configurations

Turbocharger and Performance Ratings

The addition of a turbocharger on the 12V71 boosts the airflow to support higher fuel input, significantly increasing horsepower without drastically raising engine displacement or component wear.

  • Turbocharger Type: Roots-type blower with turbo assist

  • Rated Horsepower Range:

    • Marine: 525–650 HP at 2,100 RPM (commonly seen at 625 HP for turbocharged high-output marine builds)

    • Industrial: 500–600 HP depending on torque converter, PTO configuration, and duty cycle

  • Maximum Torque: ~1,400–1,600 lb-ft at 1,200–1,600 RPM

  • Boost Pressure (Typical): 14–22 psi (varies by application and turbo size)

  • Governed Speed: 2,100–2,300 RPM depending on use case

Dimensions and Weight

  • Length: ~80 inches

  • Width: ~40 inches

  • Height: ~50 inches

  • Dry Weight: ~3,075–3,200 lbs (varies slightly with turbocharger and accessories)

Lubrication & Oil System

  • Oil Capacity: Approximately 10–12 gallons (37.9–45.4 liters)

  • Oil Pressure (Normal Operating Range): 40–60 psi

  • Oil Type: SAE 40 (straight weight) for most climates, or 15W-40 multigrade for variable temps


Engine Applications for the Detroit Diesel 12V71 Turbo

The Detroit Diesel 12V71 Turbo was designed with flexibility in mind, making it one of the most widely used powerplants across multiple sectors. The engine’s two-stroke design, combined with turbocharging, enables quick throttle response, high power-to-weight ratios, and robust reliability in harsh conditions. Below are its most common use cases by industry:

1. Commercial Marine Applications

Detroit’s 12V71 Turbo is a top choice for commercial marine vessels that demand durability and easy serviceability. Thanks to its high torque and simple mechanical layout, it is especially popular in:

  • Tugboats

  • Shrimp boats

  • Crabbers

  • Commercial fishing trawlers

  • Harbor workboats

  • Charter yachts

  • Pilot boats

  • Oil spill response vessels

Typical marine configurations use twin 12V71 Turbo engines, delivering a combined output of 1,200+ HP. These are often paired with Twin Disc or Allison marine transmissions, which Diesel Pro also supports with complete parts kits.

2. Military and Defense Applications

The 12V71 Turbo has been used extensively in the defense industry for its performance in rough terrain and quick response in combat zones:

  • M123 and M127 10-ton trucks

  • Landing craft

  • Armored recovery vehicles

  • Heavy tracked transporters

  • Mobile power units

Its modularity, coupled with high torque at low RPMs, made it ideal for heavy-duty deployment. Many U.S. military surplus engines have since found new homes in marine rebuilds and industrial equipment.

3. Industrial Equipment

In the industrial world, the 12V71 Turbo found use powering:

  • Oilfield equipment

  • Water pumps

  • Rock crushers

  • Drill rigs

  • Portable compressors

  • Large gensets (standby and prime)

Its steady RPM performance and torque output made it ideal for long running hours in remote locations, especially in Latin America, the Gulf region, and Southeast Asia.

4. Off-Highway Equipment

In mining, logging, and other off-highway sectors, the 12V71 Turbo supported operations with:

  • Articulated dump trucks

  • Log skidders

  • Track drills

  • Dozers

  • Heavy-duty cranes

These setups benefited from the engine’s unit injector system, which allowed for simplified diagnostics and consistent fuel delivery under load.

5. Repowered and Custom Applications

The aftermarket world has embraced the 12V71 Turbo in creative ways:

  • Converted marine vessels replacing older Cummins or Caterpillar engines

  • Restored military vehicles and classic trucks

  • Custom hot rods or semi-truck showpieces (due to the engine’s iconic sound and appearance)

Diesel Pro Power supports this community with rebuild kits, turbocharger replacements, aftercoolers, gasket sets, and more.


Additional Resources


Marine Detroit Diesel 12V71 Component Maintenance Life

The Legacy of the Detroit Diesel Marine 12V71 Engine & Its Use Today

Detroit Diesel 12V71 Marine Engine Specifications (Turbo & Non-Turbo)

Detroit Diesel 6V71, 8V71, 12V71, 16V71 Engine Tune Up


Introduction to the Practical Guide to Servicing Your Detroit Diesel V71 Series Engines (6V71, 8V71, 12V71, 16V71)

Overview of the Detroit Diesel V71 Series Engines (6V71, 8V71, 12V71, 16V71)

General Service Guidelines for Detroit Diesel V71 Series Engines (6V71, 8V71, 12V71, 16V71)

Cylinder Block for Detroit Diesel V71 Series Engines (6V71, 8V71, 12V71, 16V71)

Refurbishing Cylinder Blocks for Detroit Diesel V71 Engines (6V71, 8V71, 12V71, 16V71): A Guide for Machine Shops

Cylinder Head for Detroit Diesel V71 Series Engines (6V71, 8V71, 12V71, 16V71)

Common Maintenance and Repair Needs for Detroit Diesel V71 Cylinder Heads (6V71, 8V71, 12V71, 16V71)


Best Practices for Cylinder Head Maintenance for Detroit Diesel V71 Engines (6V71, 8V71, 12V71, 16V71)

Fuel and Air Systems for Detroit Diesel 6V71, 8V71, 12V71, and 16V71 Engines

Injectors Maintenance for Detroit Diesel V71 Engines (6V71, 8V71, 12V71, 16V71)

Governor Maintenance for Detroit Diesel V71 Engines (6V71, 8V71, 12V71, 16V71)

Blowers Maintenance for Detroit Diesel V71 Engines (6V71, 8V71, 12V71, 16V71)

Air Filters Maintenance for Detroit Diesel V71 Engines (6V71, 8V71, 12V71, 16V71)

Fuel Leaks Troubleshooting for Detroit Diesel V71 Engines (6V71, 8V71, 12V71, 16V71)

Air Intake Restrictions for Detroit Diesel V71 Engines (6V71, 8V71, 12V71, 16V71)

Injector Malfunction Troubleshooting for Detroit Diesel V71 Engines (6V71, 8V71, 12V71, 16V71)

Lubrication and Cooling Systems for Detroit Diesel 6V71, 8V71, 12V71, and 16V71 Engines

Electrical and Exhaust Systems for Detroit Diesel 6V71, 8V71, 12V71, and 16V71 Engines

Troubleshooting and Preventive Maintenance for Detroit Diesel 6V71, 8V71, 12V71, and 16V71 Engines

Specifications and Torque Tables for Detroit Diesel 6V71, 8V71, 12V71, and 16V71 Engines

Safety Considerations for Detroit Diesel 6V71, 8V71, 12V71, and 16V71 Engines

Introduction to Part 2: Service Manual Insights For Detroit Diesel V71 Engines (6V71, 8V71, 12V71, 16V71)

Lubrication System: Comprehensive Guide For Detroit Diesel V71 Engines (6V71, 8V71, 12V71, 16V71)

Oil Pumps for Detroit Diesel V71 Engines (6V71, 8V71, 12V71, 16V71)

Oil Pressure Regulation For Detroit Diesel V71 Engines (6V71, 8V71, 12V71, 16V71)

Oil Filters for Detroit Diesel V71 Engines (6V71, 8V71, 12V71, 16V71)

Importance of Lubrication System Maintenance for Detroit Diesel V71 Engines (6V71, 8V71, 12V71, 16V71)

Cooling System: Comprehensive Guide For Detroit Diesel V71 Engines (6V71, 8V71, 12V71, 16V71)

Types of Cooling Systems for Detroit Diesel V71 Engines (6V71, 8V71, 12V71, 16V71)

Key Components of the Cooling System for Detroit Diesel V71 Engines (6V71, 8V71, 12V71, 16V71)

Raw Water Pump Specifics for Detroit Diesel V71 Marine Engines (6V71, 8V71, 12V71, 16V71)

Importance of Cooling System Maintenance for Detroit Diesel V71 Engines (6V71, 8V71, 12V71, 16V71)

Crankcase Ventilation System: Comprehensive Guide For Detroit Diesel V71 Engines (6V71, 8V71, 12V71, 16V71)

Detailed Torque and Specifications For Detroit Diesel V71 Engines (6V71, 8V71, 12V71, 16V71)

Service Tools: Essential Equipment for Maintenance For Detroit Diesel V71 Engines (6V71, 8V71, 12V71, 16V71)

Step-by-Step Maintenance Procedures For Detroit Diesel V71 Engines (6V71, 8V71, 12V71, 16V71)

Oil Pump Removal and Reassembly for Detroit Diesel V71 Engines (6V71, 8V71, 12V71, 16V71)

Cleaning and Replacing Oil Filters and Coolers For Detroit Diesel V71 Engines (6V71, 8V71, 12V71, 16V71)

Draining and Refilling the Cooling System For Detroit Diesel V71 Engines (6V71, 8V71, 12V71, 16V71)

Troubleshooting Guide For Detroit Diesel V71 Engines (6V71, 8V71, 12V71, 16V71)

Complete Parts Catalog for Detroit Diesel V71 Engines (6V71, 8V71, 12V71, 16V71)

Comprehensive FAQ for Detroit Diesel V-71 Series Manual (6V71, 8V71, 12V71, 16V71)

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