V16

A V16 is a piston engine with 16 cylinders split into two banks of 8, mounted at an angle to each other, typically 60 degrees or 90 degrees depending on design. Each bank has its own crankshaft journal, and both banks share a single crankshaft running along the centerline of the engine block. The V configuration allows a long-stroke engine to occupy a smaller footprint than an inline 16-cylinder would, while still producing power smoothly across a broad RPM range.

V16 engines are found almost exclusively in heavy industrial machinery and rare high-performance applications. The primary user has always been railroad locomotives: Electro-Motive Diesel (EMD) produced the EMD 567 and later the EMD 710 V16 series, which became standard in American freight and passenger locomotives from the 1940s onward. These engines typically displace 567 to 710 cubic inches per cylinder and operate at moderate RPM, around 800 to 1200, delivering smooth torque delivery critical for rail traction. A few ultra-luxury automobiles, notably the Bugatti Royale and certain Ferrari and Cadillac models of the 1930s and 1950s, employed V16s to achieve exceptional power without extreme RPM.

The primary advantage of the V16 over smaller engines is its mechanical smoothness. With 16 power strokes per crankshaft revolution when properly timed across both banks, vibration is minimal; this matters greatly in locomotives where harsh vibration damages cargo and track. The engine also handles load variation well without stalling, essential for starting heavy trains from rest. Heat dissipation is another factor: the large displacement spread across many smaller cylinders produces more uniform combustion temperatures than fewer, larger cylinders, extending bearing and valve life under sustained heavy load.

Common issues and maintenance

V16 engines are mechanically complex. Balancing cylinder firing order across two banks requires precise timing and valve overlap; any failure in one bank immediately affects overall smoothness. Spark plug count (16 in gasoline engines) and fuel injector count (16 in diesel engines) multiply the number of failure points. Oil passages and water jackets in the block are intricate, making blockages more likely than in simpler designs. Overheating in one cylinder bank can propagate to the other if cooling distribution fails. Rebuilds are expensive because many components are bank-specific.

The V16 remains a specialist tool. Modern locomotive manufacturers have largely replaced V16 diesel engines with smaller, turbocharged designs that meet emissions standards and fuel economy targets. The design persists mainly in existing locomotive fleets where proven reliability matters more than efficiency. Outside rail, the V16 is essentially historical, a reminder of when absolute smoothness and torque were worth the mechanical complexity.