Cummins B Series engine

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Cummins B Series engine
Cummins Engine (LKW).jpg
6.7 Euro 4 / 4+
Also called4B/6B/6BT/6BTA,
ConfigurationInline-4 and Inline-6
  • 3.3 L; 200 cu in (3,300 cc)
  • 3.9 L; 239.3 cu in (3,922 cc)
  • 5.9 L; 359.0 cu in (5,883 cc)
  • 6.7 L; 408.2 cu in (6,690 cc)
Cylinder bore
  • 102 mm (4.02 in)
  • 107 mm (4.21 in)
Piston stroke
  • 120 mm (4.72 in)
  • 124 mm (4.88 in)
Block materialCast iron
Head materialCast iron
ValvetrainCam-in-block 2 or 4 valves x cyl.
Compression ratio17.2:1, 17.3:1, 17.5:1
TurbochargerHolset Engineering (variable)
Fuel systemCommon rail High pressure Direct injection, symmetrical combustion chamber with 7-hole injectors
ManagementBosch Mechanical with electronic advance
Fuel typeDiesel
Oil systemWet sump
Cooling systemWater-cooled
Power output215–385 hp (160–287 kW)
Torque output440–930 lb⋅ft (597–1,261 N⋅m)
Dry weight1,100 lb (499 kg)
Emissions control technologyElectric fuel control, DPF and EGR

The Cummins B Series is a family of diesel engines produced by American manufacturer Cummins. In production since 1984, the B series engine family is intended for multiple applications on and off-highway, light-duty, and medium-duty. In the automotive segment, it is best known for its use in Dodge/Ram pickup trucks.

Since its introduction, three generations of the B series engine have been produced, offered in both inline-four and inline-six configurations in multiple displacements.

General engine features[edit]

The B-series features engine bores machined directly into the block (rather than the wet liners used on earlier Cummins engines). It was also set apart by the use of a shallow one-piece head, requiring closer tolerances than in other Cummins products.[1] The engine was first manufactured in Rocky Mount, North Carolina, and other plants were later added in Mexico, Turkey, and Darlington, UK.[2]

Every Cummins powered Dodge Pickup (since initial production in 1989) has come equipped with a turbocharger. It uses a gear-drive camshaft for extra reliability. Also specified is a deep-skirt engine block and extra-strong connecting rods. A Holset turbocharger is used. The original B Series was updated with 24 valves and an electronic engine management system to become the ISB in 1998.

First generation[edit]

5.9 Cummins in 1991 Dodge Ram with the valve covers removed exposing the valvetrain


The 3.9L/4BT Cummins is an engine in the same family as the 5,883 cc (5.9 L; 359.0 cu in) Cummins turbo-diesels. The 3.9L/4B is an inline four-cylinder turbodiesel that was popular for many step van applications, including bread vans and other commercial vehicles. It has also gained popularity as an engine swap into smaller trucks. The lowest powered 4B produces 53 hp (40 kW).[1]


More Details
5.9-liter B series Cummins

Production: 1984–1998
Camshaft drive: Gear driven
Crankshaft: Forged steel, 7 main bearings
System capacity with filter: 3.5 US gal (13 l; 2.9 imp gal)
Cooling system: 6 US gal (23 l; 5.0 imp gal) coolant
System capacity incl heater: 6.5 US gal (25 l; 5.4 imp gal) coolant
Power output: 230 hp (172 kW) at 2500 rpm (5.9 L)
Torque: 440 lb⋅ft (597 N⋅m) at 1600 rpm (5.9 L)
Compression ratio: 17.5:1

The 5,883 cc (5.9 L; 359.0 cu in) 6BT, also known as the Cummins "12-valve" was the first member of the "B" engine family to be used in a light truck vehicle. The 6BT used Bosch fuel systems, injector, and VE rotary pump and P7100 inline injection pumps. Some early 6BTs were supplied with CAV rotary pumps instead, before the Bosch system became the sole standard. This engine started life in 1984 designed as an agricultural engine, for use in Case agricultural equipment.[3][full citation needed] After 1989, the 6BT engine was used in light duty, medium duty and select heavy duty trucks and buses.[citation needed] The 6BT engine has recently become very popular for use in repowering various vehicles, in the UK they have proven very popular in the Land Rover community, commonly known as the ‘good’ conversion.[citation needed]

Appearing in the 1989–1998 Dodge Ram pickup truck, it became a popular alternative to the large gasoline V8 engines normally used in full-size pickup trucks, since it produced the torque at low engine speeds, and significantly better fuel mileage. During that time, the Dodge Ram was the only diesel pickup that did not rely on glowplugs for cold weather starting.[3]

ISB 5.9[edit]

5.9 Cummins Common rail fuel injection system
More Details
5.9-liter ISB Cummins

Production: 1998.5–2007
Camshaft drive: Gear driven
Crankshaft: Forged steel, 7 main bearings
System capacity with filter: 3 US gal (11 l; 2.5 imp gal)
Fuel system: Common rail High pressure direct injection, symmetrical combustion chamber
Management: Bosch Mechanical with electronic advance
Power output: 325 hp (242 kW) at 2900 rpm
Torque: 610 lb⋅ft (827 N⋅m) at 1600 rpm
Compression ratio: 17.2:1
Emissions control: Electric fuel control

The 5.9 L; 359.0 cu in (5,883 cc) ISB (Interact System B) is one of the largest straight-six engines used for light truck vehicles and school buses, and the improved high output 600 version was on the Ward's 10 Best Engines list for 2004.

One unusual feature of the ISB is that it is a multi-valve pushrod engine design. The engine displaces 5.9 L; 359.0 cu in (5,883 cc), with a 102 mm × 120 mm (4.02 in × 4.72 in) cylinder bore and piston stroke. A turbocharger is used to increase the output in the high-compression (17.2:1 in recent versions) diesel. It is an all-iron engine with forged steel connecting rods, an assembled camshaft, and a cast aluminum intake manifold. The engine is produced in Columbus, Indiana.

The ISB uses electronically controlled Bosch fuel systems, unlike the 6BT systems which were mechanical. Early ISB engines utilize Bosch injectors and a Bosch VP44 high pressure pump. Later ISB designs have common rail fuel injection, Bosch injectors, and a Bosch CP3 high pressure pump.[3]


The 5.9 L; 359.0 cu in (5,883 cc) QSB (Quantum System B) is the off-road, heavy duty version of the ISB. Typically used in marine, agricultural, and construction applications, these engines share many of the same parts as the ISB and utilize the same Bosch fuel system.[citation needed]

Dodge Ram ISB[edit]

Midway through model year 1998, the Dodge Ram switched from the 6BT to the ISB to meet updated emissions requirements. Like other ISB's, these engines started out using the Bosch VP44 rotary injection pump. The VP44 setup meant that timing and fuel could be precisely controlled, which led to cleaner emissions. However, VP44 failure rates were higher than the older P7100 injection pump. The compression ratio in these engines was 17.2:1. The 1998–2000 ISB was rated at 215 hp (160 kW; 218 PS) and 420 lb⋅ft (569 N⋅m) when equipped with the 47RE automatic transmission. The 1998 ISB was rated at 235 hp (175 kW; 238 PS) and 460 lb⋅ft (624 N⋅m) when equipped with the manual transmission. The 1999–2000 ISB was rated at 235 hp (175 kW; 238 PS) and 460 lb⋅ft (624 N⋅m) when equipped with a manual transmission. For the 2001–2002 model years, a standard output and a high output ISB Cummins engine were offered. The standard output, which was the same as the previous engines was rated to 235 hp (175 kW; 238 PS) and 460 lb⋅ft (624 N⋅m) when equipped with either a manual transmission or automatic. The high output ISB was rated at 245 hp (183 kW; 248 PS) and 505 lb⋅ft (685 N⋅m), with only a NV5600 six-speed manual transmission available. The high output engine was different in a few ways from the standard output engine; it had higher compression (17.1:1), powdered metal valve seat inserts, a larger flywheel, the Bosch fuel system was reworked to allow higher fuel flows, and fuel-injection timing was altered.

Dodge Ram ISB CR[edit]

For the 2003 model year, the Cummins was introduced with Bosch high pressure common rail fuel injection, again increasing power output. On automatic equipped vehicles, the 47RE was upgraded internally to increase durability and torque capacity, now known as the 48RE. The 2003 rating for the Dodge truck was released at 305 hp (227 kW; 309 PS) and 555 lb⋅ft (752 N⋅m). Midway through the 2004 model year, the Cummins 600 was introduced, producing 325 hp (242 kW; 330 PS) at 2,900 rpm and 600 lb⋅ft (813 N⋅m) at 1,600 rpm. This engine was noticeably quieter than the previous engines.[4][non-primary source needed]

ISB 6.7[edit]

6.7 Demo
More Details
6.7-liter ISB Cummins

Production: 2007–present
Displacement: 6.7 L; 408.2 cu in (6,690 cc)
Bore x stroke: 107 mm × 124 mm (4.21 in × 4.88 in)
Max power: 150–385 hp (112–287 kW; 152–390 PS) at 2800 rpm
Torque: 610–930 lb⋅ft (827–1,261 N⋅m) at ~1600 rpm
Compression ratio: 17.3:1
Emissions control: EGR and DPF
Turbocharger: Holset Engineering (variable)
Fuel system: Common rail High pressure direct injection with 7-hole injectors
Camshaft drive: Gear driven
Crankshaft: Forged steel, 7 main bearings
Oil System capacity with filter: 3 US gal (11 l; 2.5 imp gal)

The B6.7 is the latest version of the B Series. It is currently the largest straight-six engine produced for a light duty truck. It produces 350 hp (261 kW; 355 PS) and 650 lb⋅ft (881 N⋅m) in the 2007.5 and newer Dodge 2500/3500 pickup trucks with the Chrysler-built six-speed 68RFE automatic transmission built at the Kokomo Transmission plant in Kokomo, Indiana. Engine torque is slightly reduced with the Mercedes G56 6-speed manual transmission at 350 hp (261 kW; 355 PS) and 610 lb⋅ft (827 N⋅m). The 2007 and newer 3500 Cab & Chassis trucks only get the 305 hp (227 kW; 309 PS) and 610 lb⋅ft (827 N⋅m) version of the B6.7, whether it has the Aisin AS68RC or the Mercedes G56 6-speed manual transmission. As for the 2008 4500/5500 medium duty Chassis Cabs or the Sterling Bullet Trucks, they receive the 350 hp (261 kW; 355 PS) and 610 lb⋅ft (827 N⋅m) version of the B6.7, whether it has the Aisin AS68RC or the Mercedes G56 6-speed manual transmission. Late model 2011 Ram trucks produce 350 hp (261 kW; 355 PS) and 800 lb⋅ft (1,085 N⋅m), with the exhaust brake rating boosted from 150 hp (112 kW; 152 PS) to 222 hp (166 kW; 225 PS).[5]

Changes over the 5.9[edit]

There are many changes over the previous B5.9 for the Dodge truck, the most obvious being the larger displacement. The B6.7 had an increase of cylinder bore and piston stroke to 107 mm × 124 mm (4.21 in × 4.88 in), respectively, thereby giving a displacement of 6.7 L; 408.2 cu in (6,690 cc).[6][full citation needed]


The two-thirds version of the ISB is the 4-cylinder 4.5-liter at 185 hp (138 kW), used in the New Routemaster, a series hybrid diesel-electric doubledecker bus in London.[7][8][9]


  1. ^ a b Kennett, Pat (June 1986). "The Cummins Beat". TRUCK. London, UK: FF Publishing Ltd: 54–55.
  2. ^ Kennett, p. 57
  3. ^ a b c Cummins 5.9-liter and 6.7-liter inline six-cylinder diesel engines. Retrieved on 2011-08-04.
  4. ^ "ISB web". Retrieved 30 April 2012.
  5. ^ 2011 Ram 2500 and 3500 – Capability – Powertrain Archived 2011-02-24 at the Wayback Machine. Retrieved on 2011-08-04.
  6. ^ Cummins Engines Archived 2009-04-25 at the Wayback Machine. Retrieved on 2011-08-04.
  7. ^ "New Bus for London: Your New Routemaster questions answered". CBS Interactive. January 5, 2012. Retrieved 2017-11-27.
  8. ^ "LESA44T" (PDF). Wrights Group Limited. 2014. Retrieved 2017-11-27.
  9. ^ Wrights Hybrid Wrightbus