Detroit Diesel 12V-71 engine specs at Barrington Diesel Club

Barrington Diesel Club

At Barrington diesel club bolt tightening torques and fuel consumption rates are provided for many engines beginning with Detroit Diesel,Cummins, and ADE. Our Web Log provides a forum for discussing diesel engine features and problems. We also provide general technical data such as Standard Torques for bolts and nuts, Properties of materials like the melting and boiling points of metals, metric to imperial cross references, SAE Flywheel housing sizes, as well as providing articles of general interest like discussions on fuel consumption and Detroit Diesel Air Box Pressures.

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Specs for Detroit Diesel 12V-71 engines and technical data provided courtesy of Barrington Diesel Club

Data provided based on Detroit Diesel printed literature

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Detroit Diesel 12v-71 Power at sea level (Industrial Engines)

description	12v-71N - N65 Injectors	description	12v-71T - N70 Injectors
rpm	1200	1400	1600	1800	2000	2100	rpm	1200	1400	1600	1800	2000	2100
Horse Power SAE	294	344	390	432	444	476	Horse Power SAE	338	396	449	497	511	547
Power Kw	219	257	291	322	331	355	Power Kw	252	295	334	370	381	408
.	.	.	.	.	.	.	.	.	.	.	.	.	.
Torque Ft lbs	1287	1290	1280	1260	1166	1190	Torque Ft lbs	1480	1484	1472	1450	1341	1369
Torque Nm	1745	1750	1736	1709	1581	1614	Torque Nm	2007	2012	1996	1966	1818	1856
.	.	.	.	.	.	.	.	.	.	.	.	.	.
Fuel Consumption l/hour	68.9	77.0	87.3	94.4	94.6	101.5	Fuel Consumption l/hour	74.8	84.3	93.2	101.9	103.4	112.3
.	.	.	.	.	.	.	.	.	.	.	.	.	.
Max Toque Ft lbs	1290 @ 1400 rpm	Max Toque Ft lbs	1484 @ 1400 rpm
Max Torque Nm	1750 @ 1400 rpm	Max Torque Nm	2012 @ 1400 rpm

Detroit Diesel 12v-71 Power at sea level (Industrial Engines) BDC Logo

description

12v-71N - N65 Injectors

description

12v-71T - N70 Injectors

rpm

1200

1400

1600

1800

2000

2100

rpm

1200

1400

1600

1800

2000

2100

Horse Power SAE

294

344

390

432

444

476

Horse Power SAE

338

396

449

497

511

547

Power Kw

219

257

291

322

331

355

Power Kw

252

295

334

370

381

408

Torque Ft lbs

1287

1290

1280

1260

1166

1190

Torque Ft lbs

1480

1484

1472

1450

1341

1369

Torque Nm

1745

1750

1736

1709

1581

1614

Torque Nm

2007

2012

1996

1966

1818

1856

Fuel Consumption l/hour

68.9

77.0

87.3

94.4

94.6

101.5

Fuel Consumption l/hour

74.8

84.3

93.2

101.9

103.4

112.3

Max Toque Ft lbs

1290 @ 1400 rpm

Max Toque Ft lbs

1484 @ 1400 rpm

Max Torque Nm

1750 @ 1400 rpm

Max Torque Nm

2012 @ 1400 rpm

Physical Characteristics Detroit Diesel 12v-71N
Weight	3210 lbs	1456 kgs
Length	60"	1524 mm
Width	46"	1168 mm
Height	57"	1448 mm
Compression Ratio	18.7:1
Displacement	852 Cu Inches	13,962 ml
Bore	4.250 inches	107.95 mm
Stroke	5.00 inches	127.00 mm

Physical Characteristics Detroit Diesel 12v-71N

Weight

3210 lbs

1456 kgs

Length

60"

1524 mm

Width

46"

1168 mm

Height

57"

1448 mm

Compression Ratio

18.7:1

Displacement

852 Cu Inches

13,962 ml

Bore

4.250 inches

107.95 mm

Stroke

5.00 inches

127.00 mm

Torque specifications Detroit Diesel 12v-71N Engine
Torques (Non standard)	Bolt Size	Ft Lbs	Nm
Air box cover	3/8 NC	15	20
Con Rod bolts / Big Ends	7/16 NF	67	90
Cam and Balance-shaft nuts	1 1/8 NF	300	407
Cam follower guide bolts	¼NC	15	20
* Crank end bolt	1" NF	290	393
* Cylinder head	5/8 NC	184	250
Flywheel Housing Bolts	1/2 NC	95	130
Fuel Connectors	7/16 NF	35	45
Fuel Line Nuts	3/8 NF	15	20
Idler gear hub bolts	3/8 NC	40	54
Injector clamp bolts	3/8 NC	25	34
* Mains	5/8 NC	184	250
Rocker shaft bolts	1/2 NC	96	130
Sump bolts	5/16 NC	10	14
* Flywheel bolts	9/16 NF	184	250
.	.	.	.
*	Lubricate with 'International Compound No 2, or Copper-Slip' or equivalent.

Torque specifications Detroit Diesel 12v-71N Engine

Torques (Non standard)

Bolt Size

Ft Lbs

Air box cover

3/8 NC

Con Rod bolts / Big Ends

7/16 NF

Cam and Balance-shaft nuts

1 1/8 NF

300

407

Cam follower guide bolts

¼NC

* Crank end bolt

1" NF

290

393

* Cylinder head

5/8 NC

184

250

Flywheel Housing Bolts

1/2 NC

130

Fuel Connectors

7/16 NF

Fuel Line Nuts

3/8 NF

Idler gear hub bolts

3/8 NC

Injector clamp bolts

3/8 NC

* Mains

5/8 NC

184

250

Rocker shaft bolts

1/2 NC

130

Sump bolts

5/16 NC

* Flywheel bolts

9/16 NF

184

250

Lubricate with 'International Compound No 2, or Copper-Slip' or equivalent.

71 Series Pistons

On Cross-Head pistons - Torquing con rod to piston/gudgeon pin

Caution - Failure of piston pin retainer bolts is always catastrophic, often a hole in the block - it happened on two occasions to me while dyna-testing engines
Suggestion - Apply locktite (or equivalent thread lock compound) to the 7/16 NF bolts
torque to 60 lb-ft, 80 Nm; do not exceed torque

Installing piston/gudgeon pin retainer plates

Caution - Leaking retainer plates are only remedied by extensive rework, i.e. head and sump at least must be removed again.
Suggestion - Apply shellac (or equivalent compound) to rim of retainer plates
Rap retainer plate into place with a domed/rounded object of similar size to the plate. (small machined nylon rod is ideal)
Allow shellac to dry (overnight)
Test piston plate seal by pouring power-paraffin or diesel into the inverted piston, the outside of the plate must remain completely dry, let it stand for a few minutes before using it to make sure.

Selected Settings for the Detroit Diesel 12V-71N
Set	Inches	mm
Injectors (N60)	1.460	37.10
Injectors (N65 brown tag)	1.484	37.69
Valves (4v head -cold)	0.016	0.41
Valves (2v head -cold)	0.012	0.30

Selected Settings for the Detroit Diesel 12V-71N

Set

Inches

Injectors (N60)

1.460

37.10

Injectors (N65 brown tag)

1.484

37.69

Valves (4v head -cold)

0.016

0.41

Valves (2v head -cold)

0.012

0.30

Standard Sizes and useful clearances Detroit Diesel 12v-71N
Part	Min inches	Max inches	Limits ins	Min mm	Max mm	Limits mm
Con Rod - ID Small End Bush	1.5025	1.5030	1.5080	38.1635	38.1762	38.3032
Con Rod - Length center to center	10.1240	10.1260	.	257.1496	257.2004	.
Crankshaft end float	0.0040	0.0160	.	0.10	0.41	.
Crankshaft Big end Std Diameter	2.9990	3.0000	.	76.1746	76.2000	.
Crankshaft Mains Std Diameter	4.4990	4.5000	.	114.2746	114.3000	.
Cyl liner - flange below block	0.0450	0.0500	0.0500	1.1430	1.2700	.
Cyl Liner - flange below block variation	0.0000	0.0020	.	0.00	0.05	.
Cyl Liner - ID	4.2495	4.2511	.	107.9373	107.9779	.
Cyl Liner - OD Std	4.6250	4.6260	.	117.4750	117.5004	.
Piston skirt diameter	4.2428	4.2450	.	107.7671	107.8230	.
Ring gap - compression rings	0.0180	0.0430	0.0600	0.4572	1.0922	1.5200
Ring gap - oil rings	0.0050	0.0140	0.0340	0.1270	0.3556	0.8636

Standard Sizes and useful clearances Detroit Diesel 12v-71N

Part

Min inches

Max inches

Limits ins

Min mm

Max mm

Limits mm

Con Rod - ID Small End Bush

1.5025

1.5030

1.5080

38.1635

38.1762

38.3032

Con Rod - Length center to center

10.1240

10.1260

257.1496

257.2004

Crankshaft end float

0.0040

0.0160

0.10

0.41

Crankshaft Big end Std Diameter

2.9990

3.0000

76.1746

76.2000

Crankshaft Mains Std Diameter

4.4990

4.5000

114.2746

114.3000

Cyl liner - flange below block

0.0450

0.0500

1.1430

1.2700

Cyl Liner - flange below block variation

0.0000

0.0020

0.00

0.05

Cyl Liner - ID

4.2495

4.2511

107.9373

107.9779

Cyl Liner - OD Std

4.6250

4.6260

117.4750

117.5004

Piston skirt diameter

4.2428

4.2450

107.7671

107.8230

Ring gap - compression rings

0.0180

0.0430

0.0600

0.4572

1.0922

1.5200

Ring gap - oil rings

0.0050

0.0140

0.0340

0.1270

0.3556

0.8636

Tune up & useful information 12v-71N Detroit Diesel engines
Item	Condition
Altitude deration	2.5% for every 300 m or 1000 ft
Cooling System capacity	52 litres
Firing Order RH Rotation Engine	1L-3R-3L-2R-2L-1R
Oil consumption	normal 200 to 400 ml per hour
Oil pan capacity	average 45 litres, full mark 50 mm below sump top
Speed full load max	Most common at 2100 rpm
Speed no load max	Most common at 2275 rpm
Speed at idle	commonly at 680 rpm

Tune up & useful information 12v-71N Detroit Diesel engines

Item

Condition

Altitude deration

2.5% for every 300 m or 1000 ft

Cooling System capacity

52 litres

Firing Order RH Rotation Engine

1L-3R-3L-2R-2L-1R

Oil consumption

normal 200 to 400 ml per hour

Oil pan capacity

average 45 litres, full mark 50 mm below sump top

Speed full load max

Most common at 2100 rpm

Speed no load max

Most common at 2275 rpm

Speed at idle

commonly at 680 rpm

Operating Conditions 12v-71N series engines
Item	Condition
Compression (sea level)	New parts - average 39 bar
Compression (sea level)	New parts - min 35 bar @ 600 rpm
Fuel Pressure @ 1500 rpm	3 bar
Oil Pressure - normal operation	3.5 bar
Oil Pressure - idle	0.8 bar
Oil Temperature - sump	90-113°C
Water Temperature	77-91°C

Operating Conditions 12v-71N series engines

Item

Condition

Compression (sea level)

New parts - average 39 bar

Compression (sea level)

New parts - min 35 bar @ 600 rpm

Fuel Pressure @ 1500 rpm

3 bar

Oil Pressure - normal operation

3.5 bar

Oil Pressure - idle

0.8 bar

Oil Temperature - sump

90-113°C

Water Temperature

77-91°C