Parts for Detroit Diesel 371 Non-Turbo - (2 Valve Head Type)

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Engine Specifications & Applications of the Detroit Diesel 3-71 Naturally Aspirated Engine (2-Valve Cylinder Head)

Overview: Detroit Diesel 3-71 NA with 2-Valve Head

The Detroit Diesel 3-71 Naturally Aspirated Engine with 2-Valve Head is a compact, two-stroke inline 3-cylinder engine known for its mechanical simplicity, field serviceability, and long-lasting durability. As part of the legendary 71 Series, the 3-71 NA was designed for continuous-duty operation in marine, industrial, and utility environments where space, weight, and dependability matter.

This 2-valve configuration features one exhaust valve per cylinder—no intake valves are present, as the engine uses a Roots-type blower to deliver intake air through ports in the cylinder liner. The result is a powerful, straightforward engine ideal for support systems and low- to mid-power output needs.

Diesel Pro Power proudly supports this platform with a full range of aftermarket replacement parts engineered for 2-valve cylinder heads.

Technical Specifications: Detroit 3-71 Naturally Aspirated (2-Valve Head)

Specification	Value
Engine Configuration	Inline 3-cylinder, two-stroke diesel
Displacement	213 cu in (3.5 liters)
Bore x Stroke	4.25 in x 5.00 in
Aspiration	Naturally Aspirated (Blower only)
Cylinder Head Type	2-Valve (1 exhaust valve per cylinder)
Horsepower Output	85–95 HP @ 2,100 RPM
Torque Output	~230–250 lb-ft
Cooling System	Water-cooled
Oil Capacity	~8 quarts
Blower Type	Roots-style positive displacement
Fuel System	Mechanical unit injectors
Dry Weight	~1,100 lbs

This engine is renowned for its consistent output, simple design, and easy access to components for fast field service.

Key Benefits of the 2-Valve Detroit 3-71 NA

Simplified Head Design: One exhaust valve per cylinder reduces valve train complexity.
No Intake Valves Needed: Fresh air enters via cylinder liner ports under blower pressure.
Lower Maintenance Cost: Fewer moving parts means fewer replacement intervals.
Excellent Fuel Efficiency at Low Loads: Optimized for long-run, steady-state operation.
Compact and Lightweight: Easy to install in confined engine compartments.