detroit series 71

The Enduring Legacy of the Detroit Diesel Series 71 Engine

The Detroit Diesel Series 71 is a two-stroke diesel engine that gained widespread popularity in various applications, from trucks and buses to construction equipment and marine vessels. Known for its distinctive sound and robust design, the Series 71 has a long and storied history. Its modular design, where cylinders could be added or removed to create different engine configurations, contributed significantly to its versatility and market appeal.

What is the Detroit Diesel Series 71?

The Detroit Diesel Series 71 is a family of two-stroke diesel engines manufactured by Detroit Diesel Corporation (later part of General Motors and then DaimlerChrysler). The “71” refers to the displacement of each cylinder in cubic inches. The engines were produced in configurations ranging from inline three-cylinder models to V16 versions, making them adaptable for a wide range of uses. The Series 71 is notable for its use of unit injectors and its two-stroke design, which resulted in high power output for its size and weight.

Key Features and Design

Several design elements contributed to the Series 71’s success:

• Two-Stroke Cycle: Unlike four-stroke engines, the Series 71 completes a power cycle every revolution, offering more power for a given engine size.
• Unit Injectors: Each cylinder has its own injector, simplifying the fuel system and allowing for precise fuel metering.
• Modular Design: The ability to easily add or remove cylinders allowed for engines of varying power outputs, suiting diverse applications.
• Robust Construction: The Series 71 was known for its durability and longevity, making it a favorite in demanding environments.

Applications of the Series 71

The Detroit Diesel Series 71 found widespread use in:

• On-Highway Vehicles: Trucks, buses, and motorcoaches.
• Off-Highway Equipment: Construction equipment, mining equipment, and agricultural machinery.
• Marine Applications: Boats, ships, and yachts.
• Stationary Applications: Generators and pumps.

Why the “Screaming Jimmy” Nickname?

The Detroit Diesel Series 71 earned the nickname “Screaming Jimmy” due to its distinctive, high-pitched exhaust note. This sound was a result of its two-stroke design and the Roots-type blower used for scavenging the cylinders. While some found the sound annoying, others associated it with power and reliability.

More information about these engines can be found on Detroit Diesel Series 71 Wikipedia page.

Frequently Asked Questions

What is the difference between a 2-stroke and 4-stroke engine?

A 2-stroke engine completes a power cycle in one revolution of the crankshaft, while a 4-stroke engine requires two revolutions. This generally leads to a higher power-to-weight ratio in 2-stroke engines, but often at the expense of fuel efficiency and emissions.

What does the “71” in Series 71 refer to?

The “71” refers to the displacement of each cylinder in cubic inches.

Why was the Detroit Diesel Series 71 so popular?

Its popularity stemmed from its robust design, high power output for its size, modular construction, and relatively simple maintenance.

Are Detroit Diesel Series 71 engines still in production?

No, the original Detroit Diesel Series 71 is no longer in production. However, many are still in operation, and parts are often available.

What is a unit injector?

A unit injector combines the fuel pump and injector into a single unit for each cylinder, allowing for more precise fuel control and eliminating the need for high-pressure fuel lines.

Summary

The Detroit Diesel Series 71 engine, affectionately known as the “Screaming Jimmy,” remains a significant piece of engineering history. Its innovative two-stroke design, unit injectors, and modular construction made it a versatile and powerful engine that saw widespread use in various applications. Although no longer in production, its legacy lives on through the many engines still operating and the enduring stories of its reliability and distinctive sound.