What Is a Detroit Diesel 2-71 Engine Worth Today

[MikePhua]

Quick answer
A running Detroit Diesel 2-71 stationary engine with clutch and pulley typically sells for $750 to $1,500 USD, depending on condition, configuration, and buyer interest. Engines with power unit setups or historical value may fetch more, while worn or incomplete units sell for less.
Detroit Diesel 2-71 development and legacy
The Detroit Diesel 2-71 is a two-cylinder, two-stroke diesel engine introduced in the 1930s by General Motors’ Detroit Diesel Division. The “2-71” designation refers to two cylinders with 71 cubic inches of displacement each, totaling 142 cubic inches. These engines were part of the legendary Series 71 family, which included configurations from inline-2 to V-16.
The 2-71 was widely used in:

• Stationary power units
  
• Small cranes and winches
  
• Sawmills and belt-driven equipment
  
• Military auxiliary systems
  

Its compact size, mechanical simplicity, and ability to run under harsh conditions made it a favorite in remote operations. However, it was also known for its high noise levels and fuel consumption, especially compared to modern four-stroke diesels.
Typical configurations and features
A 2-71 engine configured as a power unit often includes:

• Hand clutch and belt pulley: For driving sawmills or pumps
  
• Stationary stand or skid mount
  
• Mechanical governor and throttle linkage
  
• No fuel tank: Often integrated into the equipment it powered
  

Some units include an emergency air shutoff assembly mounted on the blower, a safety feature to prevent engine runaway in case of uncontrolled fuel intake.
Current market value and pricing factors
The value of a 2-71 engine depends on several factors:

• Running condition: A clean, smooth-running engine with good compression is worth more
  
• Completeness: Missing fuel tanks, starters, or clutch assemblies reduce value
  
• Application history: Engines from cranes or military units may have unique mounts or wear patterns
  
• Visual condition: Excessive oil leaks or corrosion suggest internal wear
  

Typical pricing:

• $750 USD: Fair price for a running but cosmetically rough unit
  
• $1,200–$1,500 USD: Clean, complete engine with clutch and pulley
  
• $2,000+ USD: Rare configurations or restored units with historical significance
  

Buyers often include collectors, restorers, and off-grid operators. One enthusiast hoped to install a 2-71 or 3-53 in a Jeep Wrangler for novelty and torque, though such swaps require extensive fabrication.
Inspection and safety tips
Before purchasing or starting a 2-71:

• Check for emergency shutoff: A lever near the blower should close the air intake
  
• Inspect the air intake: Cover it during first start to prevent runaway
  
• Verify clutch engagement: Hand clutches may be worn or seized
  
• Test compression and oil pressure: Even worn 2-71s can run, but performance suffers
  

If the engine hasn’t run in years, expect to replace seals, clean injectors, and flush the cooling system.
Conclusion
The Detroit Diesel 2-71 remains a sought-after relic of industrial history. While noisy and inefficient by modern standards, its rugged design and mechanical charm attract collectors and operators alike. A fair market value ranges from $750 to $1,500 USD, with condition and configuration driving price. For those who appreciate the growl of a two-stroke diesel, the 2-71 is a timeless machine worth preservin