The EMD 710 is a line of diesel engines built by Electro-Motive Diesel (previously General Motors' Electro-Motive Division). The 710 series replaced the earlier EMD 645 series when the 645F series proved to be unreliable in the early 1980's 50-series locomotives which featured a maximum engine speed of 950 rpm. The EMD 710 is a relatively large medium speed two-stroke diesel engine that has 710 cubic inches (11.6 liters) displacement per cylinder, and a maximum engine speed of 900 rpm. Since its introduction, EMD has continually upgraded the 710G diesel engine. Power output has increased from 3,800 horsepower (2,800 kW) on 1984's 16-710G3A to 4,500 horsepower (3,400 kW) (as of 2012) on the 16-710G3C-T2, although most current examples are 4,300 horsepower (3,200 kW).
The 710 has proved to be exceptionally reliable, but the earlier 645 is still supported and most 645 service parts are still in new production, as many 645-powered GP40-2 and SD40-2 locomotives are still operating after four decades of trouble-free service, and these often serve as a benchmark for engine reliability, which the 710 would meet and eventually exceed, and quite a number of non-SD40-2 locomotives (SD40, SD45, SD40T-2, and SD45T-2, for example, and even some SD50s), have been rebuilt to the equivalent of SD40-2s with new or remanufactured engines and other subsystems, using salvaged locomotives as a starting point. Some of these rebuilds have been made using new 12-cylinder 710 engines in place of the original 16-cylinder 645 engines.
Over the production span of certain locomotive models, upgraded engine models have been fitted when these became available. For example, an early 1994-built SD70MAC had a 16-710G3B, whereas a later 2003-built SD70MAC would have a 16-710G3C-T1.
The engine is made in V-8, V-12, V-16, and V-20 configurations, although most current locomotive production is the V-16 engine, whereas most current marine and stationary engine production is the V-20 engine.
All 710 engines are two-stroke 45 degree V-engines. The 710, and the earlier 645 and 567, are the only two-stroke engines commonly used today in locomotives. The 710 model was introduced in 1985 and has a 1 inch (25.4 mm) longer stroke (now 11") than the 645 (9.0625" bore). The engine is a uniflow design with four poppet-type 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.
Pre-1995 engines have mechanically-controlled Unit injectors (UIs), patented in 1934 by General Motors, EMD's former owner. Post-1995 engines have electronically-controlled Unit injectors (EUIs) which fit within the same space as a Unit injector. An EUI is EMD's implementation of EFI on its large displacement diesel engines.
See EMD 645 for general specifications common to all 567, 645, and 710 engines.
Unlike the two earlier engines, which could use natural aspiration (Roots-blown scavenging) or forced aspiration (turbocharging), the 710 engine is offered only with turbocharging. The turbocharger (a combination turbo-compressor system) follows EMD's traditional design that uses a gear train and clutch to drive the compressor rotor during low engine speeds, when exhaust heat energy alone is not sufficient. At higher engine speeds, increased exhaust heat energy is sufficient to drive the turbine and the clutch disengages, turning the turbo-compressor system into a true turbocharger. While more expensive to maintain than Roots blowers, the turbocharger significantly reduces fuel consumption and emissions in higher-throttle applications, while improving high-altitude performance. In later versions, charge air, which exits the turbocharger is routed through intercoolers before it enters the engine's air boxes.
Horsepower for naturally aspirated diesel engines is usually derated 2.5 percent per 1,000 ft (304.8 m) above mean sea level, a tremendous penalty, at least 25 percent, at the 10,000 ft (3,048.0 m) plus elevations which several Western U.S. and Canada railroads operate. Turbocharging effectively eliminates this derating.
Certain models have engine controls that permit lower fuel consumption (possibly at the expense of higher emissions) or lower emissions (possibly at the expense of higher fuel consumption).
|ID||Engine type||Induction||Max rpm||Power (hp)||Power (MW)||Introduced||Locomotive(s)|
|8-710G3A-T2||V-8||Turbocharged||900||2150||1.6||2007||GP22ECO, SD22ECO, GT38ACe EFI equipped. Românian Class 63, Class 65, Class 66-2, Indonesian CC205 class.|
|12-710G3A||V-12||Turbocharged||3000||2.2||1985||GP59, F59PH, Australian National DL class, New South Wales 82 Class.|
|12-710G3B-T2||V-12||Turbocharged||3150||2.3||2007||SD32ECO EFI equipped.|
|12-710G3C-EC||V-12||Turbocharged||3200||2.3||1993||F59PHI EFI equipped.|
|12N-710G3B-EC||V-12||Turbocharged||900||3200||2.5||1998||British Rail Class 66, British Rail Class 67, Irish Rail 201 Class, EMD DE/DM30AC|
|12N-710G3B-ES||V-12||Turbocharged||900||3200||2.5||1998||WAGR S class (diesel), Downer EDI Rail GT42CU AC, Downer EDI Rail JT42C-DC.|
|16-710G3A||V-16||Turbocharged||3800||2.8||1984||GP60, GP60M, GP60B, SD60, SD60M, SD60I, SD60F, Australian National AN Class.|
|16-710G3B||V-16||Turbocharged||4000||3.0||1992||Early SD70, SD70M, SD70MAC and SD70I.|
|16-710G3B-EC||V-16||Turbocharged||4000||3.0||1997||SD70, SD70M, SD70MAC and SD70I models equipped with electronic fuel injection (EFI).|
|16-710G3B-ES||V-16||Turbocharged||4200||3.1||200?||Downer EDI Rail GT46C|
|16-710G3B-T1||V-16||Turbocharged||900||4000||3.0||2003||EPA Tier 1 Emissions compliant/EFI Equipped SD70M, SD70MAC|
|16-710G3B-T2||V-16||Turbocharged||900||4000||3.0||2005||SD70M-2 (Norfolk Southern), MP40PH-3C EPA Tier II emissions compliant/EFI equipped.|
|16-710G3C-EC||V-16||Turbocharged||4300||3.2||1995||SD75M, SD75I, SD90/43MAC EFI equipped.|
|16-710G3C-ES||V-16||Turbocharged||4300||3.2||200?||Downer EDI Rail GT46C ACe|
|16-710G3C-T1||V-16||Turbocharged||900||4300||3.2||2003||SD70M (late model), SD70MAC (late model), Alstom PL42AC EPA Tier I emissions compliant/EFI equipped.|
|16-710G3C-T2||V-16||Turbocharged||900||4300-4500||3.2||2004||SD70ACe, SD70M-2, SD70ACS EPA Tier II emissions compliant/EFI equipped.|
|20-710G3B-EC||V-20||Turbocharged||900||5000||3.7||1995||SD80MAC EFI equipped, GT50AC (Indian Railways WDG5)|
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.
- 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
- 40-series versions of the 645, save the initial teething problems with the 20-645E, which were eventually resolved, proved to be exceptionally reliable.
- Bernard Challen, Rodica Baranescu (ed.), Diesel Engine Reference Book Second Edition, Butterworth-Heinemann 1999 ISBN 0 7506 2176 1 pg 598
- The camshaft still operates the Unit injector's built-in plunger pump, as the pump's performance is unequaled in atomizing and injecting the fuel at great pressure; the electronics controls the timing of certain events within the Unit injector, thereby achieving, variously, maximum horsepower, minimum emissions or minimum fuel consumption, as directed by the engine control system.
- Pacific Southwest Railway Museum. The History of EMD Diesel Engines. Retrieved on May 11, 2005.
- 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