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Detroit Diesel Series 149

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The Detroit Diesel 149 is a series of diesel engines by Detroit Diesel which first came out in the early 1960s.


The first configuration was a naturally aspirated 12V149 rated at about 600 hp (450 kW) soon followed by a naturally aspirated 16V149 rated at about 1,000 hp (750 kW). As manufacturers in the marine, construction, mining, and many other industries required more power output, Detroit added turbocharging and intercooling to the engine. Over a period of time, Detroit Diesel continued to further the design of the engine. They finally brought the engine up to 137.5 hp (102.5 kW) per cylinder and 406 ft·lbf (550 N·m) torque per cylinder; needless to say, this is a considerable amount of power coming from 149 cubic inches (2,440 cc) per cylinder. Much of this increase in power could be contributed to DDEC III (the third generation of Detroit Diesel Electronic Controls) electronics, thermal barrier (ceramic) coating of piston domes & fire deck, by-pass valve controlled blowers and Separate Circuit Charge Cooling (SCCC) system.


The engine is available in V-8, V-12, V-16, and V-20 configurations; using the alphanumeric nomenclature utilized by Detroit Diesel, these engines were known as the 8V149, 12V149, 16V149, and 20V149. The first number indicates the number of cylinders per engine, the "V" indicates a V-type cylinder arrangement, and the last set of numbers indicates the series of the engine. Suffixes are commonplace with Detroit Diesel model designations: "T" means the engine is equipped with turbochargers, "I" for intercoolers, and "B" for by-pass Roots-type blowers. For example, a model discussed later in the article is a 20V149 TIB; it has 20 cylinders in a V-type configuration, is a series 149 engine, and is turbocharged, intercooled, and has by-pass blowers. One of the unique features of the 149 engine is its 5¾-inch bore x 5¾-inch stroke; hence, it is known as a square bore design. It has a relatively high power-to-weight ratio. The 20V149 TIB DDEC III SCCC in stand-by generator spec has an output of 2,936 hp (2,189 kW) from a capacity of 2,980 cubic inches (48,800 cc).

Design features

All 149s have overhead camshafts and the cylinder heads fit into the engine block; this is referred to as the "pothead" design. The blowers are also recessed into the block; this section of the block is called the "airbox". Above the blower is a thick piece of steel that covers the blower and seals the top section of the air box. On a turbocharged engine an intercooler and sometimes a by-pass housing is present with the intercooler housing. The 12V,16V configurations have two blocks, two crankshafts bolted together, two blowers, and four turbos. The 16V149 has dual 10-inch (250 mm) exhaust outlets with eight bolt flanges. The 20V configuration was mainly designed for haul trucks. Detroit could push the envelope of the 16V.(In the marine version it could produce 2400 HP @ 2100 RPM.) But it would require additional special parts. They wanted 2500 HP with off the shelf parts, so the 20V149 was born. It has 3 engine blocks, 3 crankshafts bolted together. The unique set up of the 20V has a 6V block on either end of a special 8V block with 6 turbos, 3 blowers and intercoolers.

End of production

The Series 149 has been out of production since around the turn of the millennium, and MTU Friedrichshafen's 4000 Series of diesel engines is helping to fill the void left by the cessation of the 149 Series' production. Like the 149, the 4000 comes in 8V-, 12V-, 16V-, and 20V- configurations.


Detroit Diesel Series 149 Wikipedia

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