Parts for Detroit Diesel 12V71 Turbo

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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.