EMD 710

All 710 engines are two-stroke 45° V engines. The 710 model was introduced in 1985 and has a 1-inch (25 mm) longer stroke (now 11 in or 279 mm) than the 645 (10 in or 254 mm stroke). The engine is uniflow scavenged with four poppet exhaust valves in the cylinder head. For maintenance, a power assembly, consisting of a cylinder head, cylinder liner, piston, piston carrier, and piston rod can be individually and relatively easily and quickly replaced. The block is made from flat, formed, and rolled structural steel members and steel forgings welded into a single structure (a "weldment"). Blocks may, therefore, be easily repaired, if required, using conventional shop tools. Each bank of cylinders has a camshaft which operates the exhaust valves and the unit injectors.[4]

Pre-1995 engines have mechanically controlled unit injectors (UIs), patented in 1934 by General Motors, EMD's former owner. Post-1995 engines have electronic unit injectors (EUIs) which fit within the same space as a mechanical unit injector.[5] The use of EUI is EMD's implementation of non-common-rail electronic fuel injection on its large-displacement diesel engines.

See EMD 645 for general specifications common to all 567, 645, and 710 engines.

Unlike the 567 or 645, which could use either Roots blowers or a turbocharger, the 710 engine is only offered with turbocharging. The turbocharger is gear-driven and has a centrifugal clutch that allows it to act as a centrifugal blower at low engine speeds (when exhaust gas flow and temperature alone are insufficient to drive the turbine) and a purely exhaust-driven turbocharger at higher speeds. The turbocharger can revert to acting as a supercharger during demands for large increases in engine output power. While more expensive to maintain than Roots blowers, EMD claims that this design allows "significantly" reduced fuel consumption and emissions, improved high-altitude performance, and even up to a 50 percent increase in maximum rated horsepower over Roots-blown engines for the same engine displacement. But, unlike the earlier 645 and 567, which could use either turbochargers or Roots blowers, EMD's clutched turbocharger is an integral part of most 710 models.

Horsepower for any naturally aspirated engine is usually derated at 2.5% per 1,000 feet (300 m) above mean sea level, a penalty which becomes extremely large at altitudes of 10,000 feet (3,000 m) or greater as power losses would exceed 25%. Forced induction effectively eliminates this derating.

Some 710 engines have been converted to, or even delivered as, Roots-blown engines with conventional exhaust-driven turbochargers. Others have received modifications that permit lower fuel consumption (but possibly at the expense of higher NOx emissions or reduced power output), lower emissions, or even higher power (at the expense of increased fuel consumption).

Like most EMD engines, the 710 is also sold for stationary and marine applications.

Stationary and marine installations are available with either a left or right-hand rotating engine.

Marine engines differ from railroad and stationary engines mainly in the shape and depth of the engine's oil sump, which has been altered to accommodate the rolling and pitching motions encountered in marine applications.

Engine Speed

• Full . . . . . . . . . . . . . . 900 RPM
• Idle . . . . . . . . . . . . . . 350 RPM

Compression Ratio . . 16:1

Brake Horsepower (ABS Rating)

• Model 710G7 Engines
  • 8-cylinder: 1800
  • 12-cylinder: 2800
  • 16-cylinder: 3600
  • 20-cylinder: 4300

• EMD 567
• EMD 645
• EMD 1010

Notes

Specific

General

• Houk, Randy (14 December 2012). "The History of EMD Diesel Engines". Pacific Southwest Railway Museum. Archived from the original on 22 July 2014. Retrieved 5 January 2015.
• John's Alaska Railroad Page. Locomotive roster. Retrieved on September 8, 2006.
• Electro-Motive Diesel. SD70ACe. Retrieved on September 8, 2006
• Electro-Motive Diesel. SD70MAC. Retrieved on April 19, 2004 (courtesy Internet Archive Wayback Machine).
• EMD SD80MAC Operators Manual - GM-EMD 1996
• EMD SD70MAC Operators Manual - GM-EMD 1998

• List of engines under Tier 0, I, and II standards
• SD70 engines (See bottom.)
• Houk, Randy (14 December 2012). "The History of EMD Diesel Engines". Pacific Southwest Railway Museum. Archived from the original on 22 July 2014. Retrieved 5 January 2015.
• EMD 710 engine A 16-710G is shown; turbocharged 567 and 645 engines appear similarly. Whether 710, 645 or 567, these engines have the same external dimensions, with the possible exception of accessories.