Cummins B Series Marine Engine Parts & Spares
Alfa Marine Spare Parts supplies Cummins B Series marine engine parts and spares for commercial vessels, workboats, fishing vessels, auxiliary engines, marine generator installations and other marine applications.
Our Cummins B Series parts sourcing covers the Cummins 4B, 4BT, 4BTA, 6BT and 6BTA engine configurations, with components for scheduled maintenance, engine repairs, top-end overhaul and complete engine rebuild requirements.
Depending on engine configuration and availability, we can source genuine, OEM and replacement Cummins B Series parts, including fuel-system components, injectors, injection pumps, cylinder heads, pistons, bearings, turbochargers, charge-air components, sea water pumps, freshwater pumps, heat exchanger components, oil pumps, gaskets, seals and overhaul components.
The Cummins B Series includes compact four-cylinder 3.9-litre and six-cylinder 5.9-litre diesel-engine configurations.
For individual engine requirements, visit:
Cummins 4B Marine Engine Parts
Cummins 4BT Marine Engine Parts
Cummins 4BTA Marine Engine Parts
Cummins 6BT Marine Engine Parts
Cummins 6BTA Marine Engine Parts
For other Cummins engines, browse our Cummins Marine Engine Parts catalogue.
For correct parts identification, provide the complete engine model, Engine Serial Number (ESN), CPL number and existing part number whenever available.
Need a specific component? Request a Quote or email request@alfamarinespareparts.com.
Cummins B Series Marine Engine Overview
The Cummins B Series is a well-established family of compact diesel engines used across marine and other heavy-duty applications.
Within the B Series, important marine-related configurations include:
Cummins 4B / 4B3.9
Cummins 4BT / 4BT3.9
Cummins 4BTA / 4BTA3.9
Cummins 6BT / 6BT5.9
Cummins 6BTA / 6BTA5.9
The four-cylinder engines are based around the 3.9-litre B Series platform, while the six-cylinder configurations use the larger 5.9-litre platform.
Depending on engine designation, the B Series can use naturally aspirated, turbocharged or turbocharged and charge-air-cooled arrangements.
These differences are important when ordering:
- Turbochargers
- Charge-air cooler components
- Intake components
- Exhaust components
- Fuel-system parts
- Cooling-system components
- Pumps
- Gaskets
- Hoses
- Marine accessories
Parts should therefore always be identified against the exact engine rather than simply ordering by the general Cummins B Series designation.
Cummins B Series Engine ModelsCummins 4B / 4B3.9
The Cummins 4B is the basic four-cylinder member of the B Series platform.
It uses an approximately 3.9-litre inline four-cylinder diesel configuration.
Parts requirements can include:
- Fuel injectors
- Fuel injection components
- Cylinder heads
- Pistons
- Piston rings
- Bearings
- Camshaft components
- Cooling-system components
- Water pumps
- Oil pumps
- Gaskets
- Seals
- Overhaul parts
For detailed information, visit our Cummins 4B Marine Engine Parts page.
Cummins 4BT / 4BT3.9
The Cummins 4BT is a turbocharged four-cylinder configuration within the B Series.
The addition of turbocharging means that turbocharger, air-intake and exhaust components must be matched to the individual engine specification.
Parts requirements can include:
- Fuel injectors
- Injection-pump components
- Cylinder heads
- Pistons
- Bearings
- Turbochargers
- Turbocharger repair components
- Intake components
- Exhaust components
- Cooling-system parts
- Water pumps
- Oil pumps
- Gaskets
- Seals
For model-specific requirements, visit our Cummins 4BT Marine Engine Parts page.
Cummins 4BTA / 4BTA3.9
The Cummins 4BTA combines the compact four-cylinder B Series architecture with turbocharging and additional charge-air cooling.
This configuration introduces additional components compared with simpler 4B and 4BT arrangements.
Parts requirements can include:
- Fuel injectors
- Fuel injection pumps
- Cylinder-head components
- Pistons
- Bearings
- Turbochargers
- Charge-air cooler components
- Intake pipes
- Exhaust components
- Sea water pumps
- Freshwater pumps
- Heat exchanger components
- Oil pumps
- Gaskets
- Seals
For model-specific information, visit our Cummins 4BTA Marine Engine Parts page.
Cummins 6BT / 6BT5.9
The Cummins 6BT is the turbocharged inline six-cylinder member of the B Series and is based around the approximately 5.9-litre platform.
Marine installations can include additional cooling and exhaust equipment such as sea water pumps, heat exchangers and oil coolers.
Parts requirements can include:
- Fuel injectors
- Fuel injection pumps
- Cylinder heads
- Pistons
- Piston rings
- Bearings
- Connecting rods
- Crankshaft components
- Turbochargers
- Water pumps
- Heat exchanger components
- Oil coolers
- Oil pumps
- Gaskets
- Seals
- Overhaul components
For detailed information, visit our Cummins 6BT Marine Engine Parts page.
Cummins 6BTA / 6BTA5.9
The Cummins 6BTA combines the six-cylinder B Series platform with turbocharging and charge-air cooling.
Compared with a 6BT configuration, the additional charge-air cooling arrangement can affect intake, cooling, pipework, hose and gasket requirements.
Parts requirements can include:
- Fuel injectors
- Fuel injection pumps
- Cylinder heads
- Pistons
- Piston rings
- Bearings
- Turbochargers
- Charge-air cooler components
- Intake components
- Exhaust components
- Sea water pumps
- Freshwater pumps
- Heat exchanger components
- Oil coolers
- Oil pumps
- Gaskets
- Seals
- Overhaul components
For detailed information, visit our Cummins 6BTA Marine Engine Parts page.
Cummins B Series Technical SpecificationsSpecification4B Family6B FamilyEngine familyCummins B SeriesCummins B SeriesEngine type4-stroke diesel4-stroke dieselCylinder configurationInline 4-cylinderInline 6-cylinderDisplacementApprox. 3.9 LApprox. 5.9 LBoreApprox. 102 mmApprox. 102 mmStrokeApprox. 119–120 mmApprox. 120 mm4B / 6BBase configurationBase configuration4BT / 6BTTurbochargedTurbocharged4BTA / 6BTATurbocharged / charge-air cooledTurbocharged / charge-air cooledFuelDieselDieselCoolingLiquid cooled / marine configuration dependentLiquid cooled / marine configuration dependentApplicationsMarine and other heavy-duty applicationsMarine and other heavy-duty applications
Exact specifications, ratings and installed equipment can vary according to engine model, CPL, production revision and marine application.
Cummins B Series Fuel System Parts
Fuel-system requirements across the B Series can include:
- Fuel injection pumps
- Fuel injectors
- Injector nozzles
- Fuel lift pumps
- Fuel filters
- Fuel lines
- Fuel fittings
- Fuel shutoff components
- Governor components
- Injection-pump components
- O-rings
- Gaskets
- Seals
Fuel-system specifications can differ according to engine model, CPL and production configuration.
For correct identification, provide the engine model, ESN, CPL and existing component number whenever possible.
Cummins B Series Fuel Injectors
We can assist with applicable fuel injector requirements for:
- Cummins 4B
- Cummins 4BT
- Cummins 4BTA
- Cummins 6BT
- Cummins 6BTA
Injector requirements can include:
- Complete injectors
- Injector nozzles
- Injector sealing components
- O-rings
- Associated fuel-system components
Do not select injectors using the B Series family name alone.
Provide the existing injector number together with the engine ESN and CPL whenever available.
Cummins B Series Fuel Injection Pumps
Fuel injection pump requirements can include:
- Complete injection pumps
- Pump repair components
- Governor components
- Fuel shutoff components
- Drive components
- Gaskets
- Seals
- Related fuel-system components
Different B Series engines can use different fuel-system arrangements.
For injection-pump identification, provide:
Engine Model + ESN + CPL + Injection Pump Number
A clear photograph of the existing pump identification plate can also assist.
Cummins B Series Cylinder Head Parts
Cylinder-head requirements can include:
- Complete cylinder heads
- Intake valves
- Exhaust valves
- Valve guides
- Valve seats
- Valve springs
- Rocker components
- Push rods
- Tappets
- Cylinder-head gaskets
- Valve-cover gaskets
- Seals
- Related hardware
Four-cylinder and six-cylinder B Series engines require different cylinder-head and related components.
Always identify whether the engine is from the 4B or 6B platform.
Cummins B Series Pistons & Internal Engine Parts
Internal-engine requirements can include:
- Pistons
- Piston rings
- Piston pins
- Connecting rods
- Connecting-rod bushings
- Main bearings
- Connecting-rod bearings
- Thrust components
- Crankshaft components
- Camshaft components
- Timing gears
- Gaskets
- O-rings
- Seals
Piston and internal-engine specifications can vary according to engine version and rating.
For major overhaul requirements, provide the ESN and CPL before components are selected.
Cummins B Series Turbocharger Parts
Turbocharging applies to important B Series configurations including:
4BT
4BTA
6BT
6BTA
Turbocharger requirements can include:
- Complete turbochargers
- Turbocharger cartridges
- Compressor components
- Turbine components
- Shafts
- Bearings
- Seals
- Oil-feed lines
- Oil-return components
- Intake connections
- Exhaust connections
- Mounting gaskets
Different engine ratings can use different turbochargers.
Provide the existing turbocharger identification number whenever available.
Cummins B Series Charge-Air Cooler Parts
The 4BTA and 6BTA configurations use additional charge-air cooling compared with simpler B and BT arrangements.
Applicable requirements can include:
- Charge-air cooler assemblies
- Cooler cores
- Covers
- Intake pipes
- Cooling connections
- Gaskets
- O-rings
- Seals
- Hoses
- Clamps
- Mounting components
Do not assume that a charge-air component from one BTA configuration fits another engine without verification.
Cummins B Series Marine Cooling Parts
Marine cooling systems can differ according to engine and vessel configuration.
Parts requirements can include:
- Sea water pumps
- Raw-water pumps
- Freshwater pumps
- Jacket-water pumps
- Heat exchangers
- Oil coolers
- Charge-air cooler components
- Thermostats
- Thermostat housings
- Cooling pipes
- Hoses
- Gaskets
- Mechanical seals
- O-rings
Marine cooling components should always be matched against the actual engine installation.
Cummins B Series Sea Water Pump Parts
Applicable marine installations can require:
- Complete sea water pumps
- Pump housings
- Pump shafts
- Impellers
- Bearings
- Mechanical seals
- Covers
- Gaskets
- O-rings
- Repair components
If the existing pump number cannot be identified, provide clear photographs together with the engine model and ESN.
Cummins B Series Freshwater Pump Parts
Freshwater or engine-coolant pump requirements can include:
- Complete water pumps
- Pump housings
- Impellers
- Shafts
- Bearings
- Mechanical seals
- Gaskets
- O-rings
- Repair components
Pump configuration can vary between B Series engine versions.
Cummins B Series Heat Exchanger Parts
Heat-exchanger-cooled marine installations can require:
- Complete heat exchangers
- Heat exchanger cores
- End covers
- End caps
- Gaskets
- O-rings
- Seals
- Cooling connections
- Mounting components
For older marine installations, the currently installed heat exchanger may differ from the engine's original configuration.
Photographs and existing component numbers are therefore useful for identification.
Cummins B Series Lubrication Parts
Lubrication-system requirements can include:
- Engine oil pumps
- Oil filters
- Oil coolers
- Oil-pressure regulators
- Oil-pressure switches
- Oil lines
- Oil-pan components
- Crankshaft seals
- Gaskets
- O-rings
Correct lubrication components should be selected according to the individual engine specification.
Cummins B Series Crankshaft & Bearing Parts
Major internal-engine requirements can include:
- Crankshafts
- Main bearings
- Connecting-rod bearings
- Thrust bearings
- Connecting rods
- Connecting-rod bushings
- Crankshaft gears
- Front crankshaft seals
- Rear crankshaft seals
- Vibration-damper components
The four-cylinder and six-cylinder platforms use different major internal components.
For major engine components, provide:
Engine Model + ESN + CPL + Existing Part NumberCummins B Series Camshaft & Timing Parts
Timing-system requirements can include:
- Camshafts
- Camshaft bushings
- Timing gears
- Gear-train components
- Tappets
- Push rods
- Rocker components
- Timing covers
- Gaskets
- Seals
Production revisions can affect component selection.
Cummins B Series Intake & Exhaust Parts
Air-intake and exhaust requirements can include:
- Intake manifolds
- Exhaust manifolds
- Turbocharger connections
- Charge-air connections
- Intake pipes
- Exhaust elbows
- Marine exhaust components
- Hoses
- Clamps
- Gaskets
- Seals
- Mounting hardware
The exact requirements depend heavily on whether the engine is a B, BT or BTA configuration.
Cummins B Series Starter & Alternator Parts
Electrical-system requirements can include:
- Starter motors
- Starter solenoids
- Alternators
- Charging-system components
- Sensors
- Switches
- Gauges
- Wiring components
- Electrical connectors
Always verify the electrical system voltage and existing component number before ordering.
Cummins B Series Gaskets & Seals
Gasket and sealing requirements can include:
- Cylinder-head gaskets
- Valve-cover gaskets
- Intake-manifold gaskets
- Exhaust-manifold gaskets
- Turbocharger gaskets
- Charge-air cooler gaskets
- Oil-pan gaskets
- Water-pump gaskets
- Crankshaft seals
- Fuel-system seals
- O-rings
- Complete gasket sets
Gasket requirements can also be prepared together with overhaul components.
Cummins B Series Overhaul Parts
For a Cummins B Series engine overhaul, Alfa Marine Spare Parts can assist with applicable:
- Pistons
- Piston rings
- Piston pins
- Main bearings
- Connecting-rod bearings
- Connecting rods
- Cylinder-head components
- Intake valves
- Exhaust valves
- Fuel injectors
- Fuel injection components
- Turbocharger components
- Charge-air cooler components
- Water pumps
- Oil pumps
- Oil cooler components
- Gaskets
- O-rings
- Seals
Overhaul requirements should always be prepared according to the exact engine model, ESN and CPL.
Cummins B Series Top-End Overhaul Parts
Top-end requirements can include:
- Cylinder heads
- Intake valves
- Exhaust valves
- Valve guides
- Valve seats
- Valve springs
- Rocker components
- Push rods
- Fuel injectors
- Cylinder-head gaskets
- Valve-cover gaskets
- O-rings
- Seals
For a complete top-end requirement, provide the engine identification information and quantities required.
Cummins 4B vs 4BT vs 4BTA
The 4B, 4BT and 4BTA belong to the same four-cylinder B Series platform, but they should not automatically be treated as identical.
In general:
4B — base four-cylinder B Series configuration
4BT — four-cylinder B Series with turbocharging
4BTA — four-cylinder B Series with turbocharging and charge-air cooling
These differences can affect:
- Turbocharger components
- Charge-air components
- Intake components
- Exhaust components
- Cooling-system components
- Fuel-system calibration
- Hoses
- Pipes
- Gaskets
- Mounting hardware
For individual engines, visit:
Cummins 4B Marine Engine Parts
Cummins 4BT Marine Engine Parts
Cummins 4BTA Marine Engine Parts
Cummins 6BT vs 6BTA
The 6BT and 6BTA belong to the six-cylinder 5.9-litre B Series platform.
The important general distinction is:
6BT — turbocharged
6BTA — turbocharged with additional charge-air cooling
That additional cooling arrangement can affect:
- Charge-air cooler components
- Intake components
- Cooling pipes
- Hoses
- Turbocharger connections
- Exhaust components
- Gaskets
- Seals
For individual engines, visit:
Cummins 6BT Marine Engine Parts
Cummins 6BTA Marine Engine Parts
Cummins B Series Marine Applications
Cummins B Series engines have been used in a wide variety of marine installations.
Depending on engine model, rating and configuration, applications can include:
- Commercial vessels
- Workboats
- Fishing vessels
- Passenger craft
- Small utility vessels
- Auxiliary engines
- Marine generator installations
- Recreational vessels
- Yacht auxiliary applications
The engine rating and installed marine equipment should always be verified from the individual engine identification.
Cummins B Series Engine Identification
Correct identification is particularly important for B Series engines because many have been in service for years and may have undergone repairs, component replacements or marinization changes.
When requesting parts, provide:
Engine family: Cummins B Series
Engine model: 4B / 4BT / 4BTA / 6BT / 6BTA
Engine Serial Number (ESN):
CPL number:
Existing part number:
Part description:
Quantity:
For fuel injection pumps, turbochargers, sea water pumps, starters, alternators and other configuration-sensitive components, clear photographs can also assist.
The preferred identification sequence is:
Engine Model + ESN + CPL + Existing Part NumberWhy Source Cummins B Series Parts From Alfa Marine Spare Parts?
Alfa Marine Spare Parts supports shipowners, vessel operators, ship managers, shipyards, marine engineers, purchasing departments, repair companies and engine rebuilders with Cummins B Series marine engine parts and spares.
Depending on availability, we can assist with:
- Routine maintenance parts
- Fuel injectors
- Fuel injection pumps
- Cylinder heads
- Pistons
- Bearings
- Internal engine components
- Crankshaft components
- Turbochargers
- Charge-air cooler components
- Sea water pumps
- Freshwater pumps
- Heat exchanger components
- Oil pumps
- Oil cooler components
- Starting-system parts
- Alternators
- Gaskets and seals
- Top-end overhaul parts
- Complete overhaul requirements
- Genuine parts
- OEM parts
- Replacement parts
For individual engine requirements, visit our Cummins 4B Marine Engine Parts, Cummins 4BT Marine Engine Parts, Cummins 4BTA Marine Engine Parts, Cummins 6BT Marine Engine Parts and Cummins 6BTA Marine Engine Parts pages.
You can also browse our Cummins Marine Engine Parts catalogue and Marine Spare Parts Catalogue.
Alfa Marine Spare Parts is an independent marine spare-parts supplier and is not an official Cummins dealer.
Frequently Asked QuestionsWhat Is the Cummins B Series?
The Cummins B Series is a diesel-engine family that includes four-cylinder and six-cylinder configurations used across marine and other heavy-duty applications.
Which Cummins B Series Engines Are Covered?
Our B Series coverage includes 4B, 4BT, 4BTA, 6BT and 6BTA configurations.
What Is the Cummins 4B Engine Size?
The four-cylinder B Series platform is commonly associated with approximately 3.9 litres of displacement.
What Is the Cummins 6BT Engine Size?
The six-cylinder 6BT platform is commonly associated with approximately 5.9 litres of displacement.
What Is the Difference Between 4B, 4BT and 4BTA?
The basic 4B is the base four-cylinder configuration, the 4BT adds turbocharging, and the 4BTA uses turbocharging with additional charge-air cooling.
What Is the Difference Between 6BT and 6BTA?
Both belong to the six-cylinder B Series platform. The 6BT is turbocharged, while the 6BTA includes additional charge-air cooling.
Can You Supply Cummins B Series Fuel Injectors?
Yes. Depending on engine configuration and availability, we can assist with applicable injectors, injector nozzles and associated fuel-system components.
Can You Supply Cummins B Series Injection Pumps?
Yes. Provide the engine ESN, CPL and existing injection-pump number whenever possible.
Can You Supply Cummins 4BT and 6BT Turbochargers?
Yes. We can assist with applicable turbochargers and associated components. The existing turbocharger identification number is recommended for accurate matching.
Can You Supply Cummins B Series Sea Water Pumps?
Yes. We can assist with applicable marine sea water pumps and related cooling-system components.
Can You Supply Cummins B Series Heat Exchanger Parts?
Yes. Depending on the installed marine configuration, we can assist with heat exchanger cores, covers, seals, gaskets and related components.
Can You Supply Cummins B Series Overhaul Parts?
Yes. We can assist with applicable pistons, bearings, cylinder-head components, fuel-system parts, turbocharger components, pumps, gaskets, seals and other overhaul requirements.
Related Cummins B Series Engine Pages
Cummins 4B Marine Engine Parts
Cummins 4BT Marine Engine Parts
Cummins 4BTA Marine Engine Parts
Cummins 6BT Marine Engine Parts
Cummins 6BTA Marine Engine Parts
Cummins C Series Marine Engine Parts
Cummins 855 Series Marine Engine Parts
Request Cummins B Series Marine Engine Parts
Looking for Cummins B Series marine engine parts, maintenance spares or overhaul components?
Send us:
Engine model: 4B / 4BT / 4BTA / 6BT / 6BTA
Engine Serial Number (ESN):
CPL number:
Existing part number:
Part description:
Quantity:
Required condition: Genuine / OEM / Replacement
Delivery destination:
Required date:
If the part number is unknown, include clear photographs of the engine identification plate and existing component.
Email: request@alfamarinespareparts.com
You can also browse our Cummins Marine Engine Parts catalogue.
Worldwide supply of Cummins B Series parts for commercial vessels, workboats, fishing vessels, shipyards, marine repair companies and engine rebuilders.