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Detroit Diesel Series 71

(Redirected from Detroit Diesel 6V71N)

The Detroit Diesel Series 71 is a two-stroke diesel engine series, available in both inline and V configurations, manufactured by Detroit Diesel. The number 71 refers to the nominal displacement per cylinder in cubic inches, a rounding off of 70.93 cu in (1.2 L).

Series 71
Detroit Diesel 6V71
Overview
ManufacturerDetroit Diesel
Production1938–1995
Layout
ConfigurationMulti-cylinder,
inline and V-type
Displacement71 cu in (1.2 L)
(per cylinder)
Cylinder bore4+1⁄4 in (108 mm)
Piston stroke5 in (127 mm)
Cylinder block materialCast iron[1]
ValvetrainPushrod-operated 2 or
4 valves per cyl.
Compression ratio18.7:1 (N/A)
17.0:1 (Turbo)
Combustion
TurbochargerOn some versions
Fuel systemUnit fuel injection
Fuel typeDiesel
Cooling systemWater-cooled
Output
Power output10–1,600 hp (7–1,193 kW)
Torque output299–2,150 lb⋅ft (405–2,915 N⋅m)
Dimensions
Length36–79 in (910–2,010 mm)
Width29–47 in (740–1,190 mm)
Height39–59 in (990–1,500 mm)
Dry weight1,525–4,820 lb (692–2,186 kg)
Chronology
SuccessorSeries 92
Series 60

Inline models included one, two, three, four and six cylinders, and the V-types six, eight, 12, 16, and 24 cylinders.

The two largest V units used multiple cylinder heads per bank to keep the head size and weight to manageable proportions, the V-16 using four heads from the four-cylinder inline model, and the V-24 using four heads from the inline six-cylinder model. This feature also assisted in reducing the overall cost of these large engines by maintaining parts commonality with the smaller models.

History edit

The inline six-cylinder 71 series engine was introduced as the initial flagship product of the Detroit Diesel Engine Division of General Motors in 1938.

This engine was in high demand during WWII, necessitating a dramatic increase in output: about 57,000 6-71s were used on American landing craft, including 19,000 on LCVPs, about 8,000 on LCM Mk 3, and about 9,000 in quads on LCIs; and 39,000 were used in armor, including 4,000 on Valentine tanks, 22,000 in double packs on M4A2s, and 11,000 on M10 tank destroyers.[2]

The V-type first appeared in 1957.

Sales of the Series 71 ceased in the summer of 1995, with the four-stroke Detroit Diesel engine introduced as a replacement.

Design edit

 
Detroit Diesel 8V-71T as used in the US M109 self-propelled howitzer

Bore and stroke are the same across all units, at 4+1⁄4 in × 5 in (108 mm × 127 mm). Inline models were famously "symmetrical," meaning that the blower, exhaust, water manifold, starter, and other components could be mounted on either side of the basic block to fit a particular application. A number of models could also run with the crankshaft turning either clockwise or counter-clockwise, called "Right Hand" or "Left Hand" rotation engines (as viewed from the front of the engine). The less-common Left Hand engines were typically used in buses, because the rotation matched rear-engined transverse installations. Boats equipped with two engines would typically use one Left Hand and one Right Hand, so that the torque from the propellers would cancel each other out, without the need for a complex reversing gear on one side.

As a two-stroke diesel engine that does not use crankcase aspiration cannot naturally draw in combustion air, the blower is inherently necessary to charge the cylinders with air for combustion. The blower also assists in scavenging spent combustion gasses at the end of the power stroke. All Series 71 engines use uniflow scavenging, in which a gear-driven Roots blower mounted to the exterior of the engine provides intake air through cored passages in the engine block and ports in the cylinder walls at slightly greater than atmospheric pressure. The engine exhausts through pushrod-operated poppet valves in the cylinder head(s), with either two or four valves per cylinder. Unit fuel injection is employed, one injector per cylinder, with no high fuel pressure outside of the injector body. The injectors are cycled from the same camshaft responsible for opening the exhaust valves.

Nomenclature edit

The first number refers to the number of cylinders in the engine, followed by a hyphen or "V", indicating inline or vee, respectively, then 71 for the Series designation, referring the nominal displacement per cylinder in cubic inches (rounding up 70.93 cu in (1.2 L)).

Like most Detroit Diesel two-cycle engines, the 71 Series are equipped with a blower yet still referred to as "naturally aspirated" (SAE designation). These do not have a model suffix identifier: 6-71 is an inline 6. When the model number includes a suffix, it denotes additional features. Engines equipped with needle unit[clarification needed] fuel injectors and commonly four exhaust valves per cylinder are indicated by the suffix "N", so for the V8, 8V-71N. Later versions were available with turbochargers, which discharged directly into the Roots blower intake; these have a "T" suffix, and with aftercooling, a "TA,, so 8V-71T or 8V-71TA. "TT" indicates Tailored Torque and "TTA" Tailored Torque Aftercooled. These models are designated for economy (Fuel Squeezer) and constant horsepower ratings.

Applications edit

 
Motor Coach Industries MC-9 bus powered by a rear-mounted 8V-71 Detroit Diesel engine.

The most popular incarnations of the series 71 engine as used for highway vehicle applications included the inline 6-71, the V-block 6V-71 (both widely used in transit buses) and the 8V-71 V-8. In addition to motorcoach propulsion, both inline and V types have found extensive usage in school buses, trucks, fire apparatus, motor homes, construction[3] and industrial machinery, a few farm tractors, commercial fishing vessels, and military vehicles and equipment.

The 71 series is very popular in marine applications, not only as a propulsion engine in small craft (Gray Marine 6-71) but as auxiliary power to drive generators, winches and other heavy shipboard machinery. The Detroit inline 6-71 engine, in all of its variations, was also available as a "pancake engine" (here variably called either 6L-71 or 6N-71) for horizontal (underfloor) mount applications, such as on larger Crown and Gillig school buses and articulated puller transit buses (such as the Crown-Ikarus 286). Many 4-71 engines were used in various types of construction equipment, such as Galion highway graders.

The six-cylinder version was also used in the Victorian Railways DERM railmotor.

Variants edit

Detroit Diesel (2 cycle) common model and suffix codes
Model codes Description
L Low profile
V V-block
N Needle Unit Injectors, four exhaust valves (per cylinder)
T Turbocharged
TA Turbocharged Aftercooled (JWAC Jacket Water Aftercooled)
TAC Turbocharged Aftercooled California Certification (JWAC Jacket Water Aftercooled)
TT Tailored Torque (Fuel Squeezer)
TTA Tailored Torque Aftercooled (Fuel Squeezer Plus) (JWAC Jacket Water Aftercooled)
TI Turbocharged Intercooled
TIB Turbocharged Intercooled Bypass Blower
Model Displacement Engine configuration Power
1-71 1.2 L (71 cu in) Single-cylinder 34 hp (25 kW)
2-71 2.3 L (142 cu in) I-2 68 hp (51 kW)
3-71 3.5 L (213 cu in) I-3 113 hp (84 kW)
4-71 4.7 L (284 cu in) I-4 160 hp (119 kW)
6-71 7.0 L (426 cu in) I-6 170 hp (127 kW)
6V-71 7.0 L (426 cu in) V-6 238 hp (177 kW)
8V-71 9.3 L (568 cu in) V-8 318 hp (237 kW)[4]
12V-71 14.0 L (852 cu in) V-12 450 hp (336 kW)
16V-71 18.6 L (1,136 cu in) V-16 635 hp (474 kW)
Series 71 specifications for selected models
Family Model Torque Power Length × Width × Height Weight
3-71 3-71[5] 299 lb⋅ft (405 N⋅m)
@ 1400 rpm 		109 hp (81 kW)
@ 2100 rpm 		36 in × 29 in × 41 in
(0.91 m × 0.74 m × 1.04 m) 		1,525 lb
(692 kg)
4-71 4-71[5][6] 385–400 lb⋅ft (522–542 N⋅m)
@ 1600 rpm 		140–152 hp (104–113 kW)
@ 2100 rpm 		42 in × 29 in × 42 in
(1.07 m × 0.74 m × 1.07 m) 		1,780 lb
(807 kg)
4-71T[7] 525 lb⋅ft (712 N⋅m)
@ 1400 rpm 		190 hp (142 kW)
@ 2100 rpm 		44 in × 31 in × 44 in
(1.12 m × 0.79 m × 1.12 m) 		1,830 lb
(830 kg)
6-71 6-71[5][8] 600–612 lb⋅ft (813–830 N⋅m)
@ 1600 rpm 		170–228 hp (127–170 kW)
@ 2100 rpm 		54 in × 29 in × 39 in
(1.37 m × 0.74 m × 0.99 m) 		2,230 lb
(1,012 kg)
6-71T[7][9] 762–801 lb⋅ft (1,033–1,086 N⋅m)
@ 1400 rpm 		275–285 hp (205–213 kW)
@ 2100 rpm 		56 in × 32 in × 50 in
(1.42 m × 0.81 m × 1.27 m) 		2,195–2,240 lb
(996–1,016 kg)
6-71TT[10] 853 lb⋅ft (1,157 N⋅m)
@ 1200 rpm 		230 hp (172 kW)
@ 1950 rpm 		56 in × 32 in × 52 in
(1.42 m × 0.81 m × 1.32 m) 		2,195 lb
(996 kg)
6V-71 6V-71[11][12] 600 lb⋅ft (813 N⋅m)
@ 1600 rpm 		228 hp (170 kW)
@ 2100 rpm 		41 in × 39 in × 48 in
(1.04 m × 0.99 m × 1.22 m) 		2,380 lb
(1,080 kg)
6V-71T[12] 725 lb⋅ft (983 N⋅m)
@ 1600 rpm 		262 hp (195 kW)
@ 2100 rpm 		41 in × 40 in × 53 in
(1.0 m × 1.0 m × 1.3 m) 		2,380 lb
(1,080 kg)
8V-71 8V-71[11][13] 800 lb⋅ft (1,085 N⋅m)
@ 1600 rpm 		304 hp (227 kW)
@ 2100 rpm 		47 in × 39 in × 51 in
(1.19 m × 0.99 m × 1.30 m) 		2,310 lb
(1,048 kg)
8V-71T[13] 965 lb⋅ft (1,308 N⋅m)
@ 1600 rpm 		350 hp (261 kW)
@ 2100 rpm 		50 in × 40 in × 53 in
(1.3 m × 1.0 m × 1.3 m) 		2,495 lb
(1,132 kg)
8V-71TA[14] 1,064 lb⋅ft (1,443 N⋅m)
@ 1200 rpm 		370 hp (276 kW)
@ 2100 rpm 		43 in × 38 in × 49 in
(1.09 m × 0.97 m × 1.24 m) 		2,415 lb
(1,095 kg)
8V-71TTA[14] 1,064 lb⋅ft (1,443 N⋅m)
@ 1200 rpm 		305 hp (227 kW)
@ 2100 rpm 		43 in × 38 in × 49 in
(1.09 m × 0.97 m × 1.24 m) 		2,415 lb
(1,095 kg)
12V-71 12V-71[11][15] 1,200 lb⋅ft (1,627 N⋅m)
@ 1600 rpm 		456 hp (340 kW)
@ 2100 rpm 		60 in × 46 in × 58 in
(1.5 m × 1.2 m × 1.5 m) 		3,210 lb
(1,456 kg)
12V-71T[15] 1,450 lb⋅ft (1,966 N⋅m)
@ 1600 rpm 		525 hp (391 kW)
@ 2100 rpm 		70 in × 46 in × 55 in
(1.8 m × 1.2 m × 1.4 m) 		3,550 lb
(1,610 kg)
16V-71

(two joined 8V71 engine blocks)

16V-71TI[16] 2,150 lb⋅ft (2,915 N⋅m)
@ 1600 rpm 		800 hp (597 kW)
@ 2100 rpm 		79 in × 47 in × 59 in
(2.0 m × 1.2 m × 1.5 m) 		4,820 lb
(2,186 kg)


Model numbers edit

Series 71 sample model numbers[citation needed]
Engine Model
numbers		 Injectors Rated gross power
kW BHP
25993 1033–5000 81
1033–7000 81
26024 1043–5000 N60 104 140
26024 1043–5000 N65 113 152
4-71 + Torque Converter 1043–5001 N65 113 152
26024 1043–7000 N60 104 140
26024 1043–7000 N65 113 152
4-71T 1043–8300 N75 142 190
26085 1063–5000 N65 170 228
26085 1063–5000 N65 228
6-71 + Torque Converter 1063–5001 N65 170 228
26085 1063–5100 N65 218
1063–7000 228
26085 1063–7000 N65 170 228
26085 1063–7100 N65 218
6-71T 1063–8300 N75 213 285
6-71T 1063–8340 7C75 205 275
6-71TT 1063–8740 7E+75 172 230
6V71 7063–7000 N65 170 228
6V71 + Torque Converter 7063–7001 N65 170 228
6V71T 7063–7300 N75 195 262
8V71 7083–7000 N65 227 304
8V71 + Torque Converter 7083–7001 N65 227 304
8V71 7087–7040 7E+65 227 304
8V71T 7083–7300 N75 261 350
8V71T 7087–7340 N75 350
7087–7344 N65 308
7087–7344 N70 335
8V71TA 7087–7640 7C75 276 370
8V71TT 7087–7340 N75 228 305
8V71TTA 7087–7940 7C75 228 305
12V71 +Torque Converter 7123–7001 340

Further developments edit

WWII General Motors 6004/6046 engine edit

The inline 6-71 was adapted to British requirements as the power plant for Canadian (and later British) built Valentine tanks where it was known as the GMC 6004, orders being placed in late September 1940.[17]

The 6046 Diesel was a twin engine setup used by US and British tanks and tank destroyers.

Detroit Diesel 6051 quad-71 edit

The Detroit Diesel 6051 quad-71 was a Detroit Diesel Series 6-71 side by side tandem engine setup of two banks of four engines each driving two propeller shafts in Landing Craft Infantry LCI(L). The eight engines produced a total of 1,600 bhp (1,193 kW).[18]

Soviet/Russian copies edit

In the Soviet Union / Russia, various versions of this engine-type were produced at the YaAZ automobile factory in Yaroslavl.[19] Throughout World War II, the 4-71 engine both in locally assembled form (built by Lend-Lease provided American industrial equipment) and from US-supplied kits had been used for Ya-12 light artillery tractors.[20] After 1945, the 4-71 engine entered production in a slightly modified configuration (deuniversalization, conversion to metric units, a more powerful preheater[21]) to suit the conditions of the Soviet Union–branded "YaAZ-204".[19] After 1947, the factory used a copy of the 6-71 engine branded "YaAZ-206" in the YaAZ-210 and YaAZ-214 heavy trucks built from 1951 to 1959. The vehicle production was transferred to KrAZ in Kremenchuk, Ukraine, in 1959, where trucks with newer versions of the YaAZ-206 stood in production until the appearance of the four-stroke V8-engined KrAZ-255 in 1967.[22][23][24][25][26]

See also edit

References edit

  1. ^ "71 Series Liner and Cylinder Block Bore Measurements". Powerlinecomponents.com. Retrieved 16 February 2019.
  2. ^ "Detroit Diesel Division of GM in World War Two". Retrieved 25 July 2023.
  3. ^ "Allis-Chalmers TS-460 motor scraper". 26 April 2017.
  4. ^ Barrington, Steve. "Detroit Diesel 8v-71 manuals and specifications". Barringtondieselclub.co.za. Retrieved 16 February 2019.
  5. ^ a b c "fan-to-flywheel models: 3-71, 4-71, & 6-71" (PDF). Detroit Diesel Engines. Retrieved 17 July 2018.
  6. ^ "fan-to-flywheel models: 4-71" (PDF). Detroit Diesel Engines. Retrieved 17 July 2018.
  7. ^ a b "fan-to-flywheel models: 4-71T & 6-71T" (PDF). Detroit Diesel Engines. Retrieved 17 July 2018.
  8. ^ "fan-to-flywheel models: 6-71" (PDF). Detroit Diesel Engines. Retrieved 17 July 2018.
  9. ^ "truck models: 6-71T" (PDF). Detroit Diesel Engines. Retrieved 17 July 2018.
  10. ^ "truck models: 6-71TT" (PDF). Detroit Diesel Engines. Retrieved 17 July 2018.
  11. ^ a b c "fan-to-flywheel models: 6V-71, 8V-71, & 12V-71" (PDF). Detroit Diesel Engines. Retrieved 17 July 2018.
  12. ^ a b "fan-to-flywheel models: 6V-71 & 6V-71T" (PDF). Detroit Diesel Engines. Retrieved 17 July 2018.
  13. ^ a b "fan-to-flywheel models: 8V-71 & 8V-71T" (PDF). Detroit Diesel Engines. Retrieved 17 July 2018.
  14. ^ a b "8V-71TA & 8V-71TTA" (PDF). Detroit Diesel Engines. Retrieved 17 July 2018.
  15. ^ a b "fan-to-flywheel models: 12V-71 & 12V-71T" (PDF). Detroit Diesel Engines. Retrieved 17 July 2018.
  16. ^ "fan-to-flywheel models: 16V-71TI" (PDF). Detroit Diesel Engines. Retrieved 17 July 2018.
  17. ^ Engines used by British vehicles
  18. ^ Allied landing craft and ships ibiblio.org
  19. ^ a b "YaAZ-204 Diesel engine" (in Russian). русская-сила.рф. Retrieved 2013-11-21.
  20. ^ "Engines of the Red Army in WW2 - Artillery Tractor Ya-12". Engines of the Red Army in WW2. 2007-03-12. Archived from the original on 2015-09-24. Retrieved 2013-11-22.
  21. ^ "Дизельный первенец ярославцев".
  22. ^ Andrei Bogomolov. "Oldtimer picture gallery. Trucks. YaAZ". Retrieved 2013-11-20.
  23. ^ Andrei Bogomolov. "Oldtimer gallery. Trucks. YaAZ-210". Retrieved 2013-11-20.
  24. ^ "KrAZ-219". OldRussianCars.com. 2013-07-21. Retrieved 2013-11-20.
  25. ^ "YaAZ-218". OldRussianCars.com. Retrieved 2013-11-20.
  26. ^ "KrAZ-222". OldRussianCars.com. Retrieved 2013-11-20.
 
Wikimedia Commons has media related to Detroit Diesel series 71 engines.

Sources edit

  • Shelton, Chris. "Then, Now, and Forever" in Hot Rod, March 2017, pp.16-29.
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