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Cummins 855 Engines

Replacement Cummins 855 Big Cam Engines For Sale

We offer a couple of different solutions when it comes to Cummins 855 Big Cam Engine Replacements: long block engines and remanufactured extended long block options. All of our Cummins 855 Big Cam Engines are built back to OEM specs or offered as direct new casting replacements. 855 Big Cam Engines are mostly suited for industrial and agricultural applications however assemblies can be used for automotive/over the road truck scenarios. Usually long blocks are better options due to the ability to use an existing fuel system governed for on-highway variable RPMs.

Cummins 855 Long Block Engine

855 Big Cam Long BlockLong block 855 Engines (1/2 - 3/4 Assembly) are suitable replacements for existing engines that have experienced catastrophic failure, but the ancillary components are still in good working order. If you spun a bearing, threw a rod through the block or dropped a valve a long block is more cost effective alternative to a more complete option. Check the turbo, fuel pump, manifolds, fuel lines and accessory drive components are undamaged before looking at a long block option. Metal shavings and lack of oil pressure can oftentimes leave unseen damage. Long blocks are a good option for both on-highway and off-highway industrial use. Cummins 855 NTC, NTA, NT, NH versions can be built to spec either as an extended long block or long block option to an ESN and CPL Number. Check with your sales representative for lead time and availability for custom engine orders.

Long block castings are new replacement assemblies. A long block includes:

  • Cylinder Block
  • Cylinder Head
  • Camshaft
  • Followers/Lifters
  • Pistons
  • Gaskets and Bearings
  • Rings
  • Plugs and Bolts
  • Push Rods
  • Thermostat
  • Connecting Rods
  • Front Cover
  • Timed Front Gear Group
  • Crankshaft
  • Oil Pump
  • Water Pump
  • Oil Cooler
  • Freeze Plugs
  • Oil pickup tube
  • Oil Pan
  • Standard 6 Months Parts Replacement Warranty
  • 1 or 2 Year Extended Warranty Available

Cummins 855 Big Cam Remanufactured Engines:

Cummins NTC 855 Big CamOur 855 Reman Engines are regarded as "extended long blocks" which are effectively whole engine assemblies. The Cummins 855 Big Cam Complete Engine is considered a more complete option for re-powers where an old worn out assembly is being replaced. We offer 855 Big Cam III and Cummins 855 Big Cam IV options up to 400 HP depending on fit an application. These engines have gone through a complete overhaul and has been remanufactured with roughly 90% new Cummins parts 10% aftermarket. The remanufactured NT 855 Engine has a new cylinder block, PTG Pump, pistons, liners, piston rings bearings, camshaft, turbo, valves rocker arms and more. The majority of the parts are brand new especially the critical wear parts. Usually, the cylinder head and injectors are remanufactured and the blocks if needed. Remanufacturing means to bring the engine back to OEM spec which not the same as a lesser "refurbishing" or "rebuilt" classification. Remanufactured engines are "like brand new" and configured to exact tolerances. The engine does not include starter, alternator, flywheel, flywheel housing variations as those components mostly are reused off the old engine. Build Sheet and Run Test Video available upon request.

NTC 855 Extended Long Block Engine Includes:

  • Engine Block (3081283)
  • Cylinder Head (4915442)
  • Camshaft and Lifters (3253960)
  • Pistons, Rings, Bearings
  • Rocker Assemblies
  • Injectors (3047991)
  • Connecting Rods
  • Crankshaft
  • PTG Fuel Pump (3021966 -With Additional VS Throttle)
  • Turbocharger (3048808)
  • Vibration Damper
  • Water Pump
  • Oil Pump
  • Oil Cooler
  • Accessory Pully
  • Air Cross Over Tubes
  • Starter (Not on Standard Builds)
  • Alternator (Not on Standard Builds)
  • Flywheel (Not on Standard Builds)
  • Flywheel Housing (Not on Standard Builds)
  • Oil Pan and Pickup Tube
  • No Core Charge
  • Comes with 12 Months Parts Replacement Warranty
  • 1 or 2 Year Extended Warranty Available

NTC 855 Engine Specs:

  • Model: NTA855-C400
  • HP: 400 HP @1800 RPM
  • CPL: 3554
  • Fuel Pump: 3021966

Cummins 855 Big Cam History and Specs

Cummins NT855 Big Cam EngineWe here at Big Bear Engine Company are proud to be able to offer replacement options for the Cummins 855 Big Cam Engine. The 855 Big Cam is regarded as one of the last true variable timing mechanical engines on the heavy duty side before electronics came into play with the N-14. The engine was first introduced in 1976 and mass produced up until 1985. After ’85 the engine was engine was still supplied by Cummins up until 2000, with engineering supersessions from 1988-1991. The Big Cam 855 replaced the Small Cam 855 of the 60s and in fact was the first engine designed to meet the new updated mandates of the Clean Air Act of 1976.

Old school truckers and farmers all loved the Cummins 855 Big Cam because of its simple design and reliability all the while producing some major horsepower and torque to get the job done in the field. The over the road truck application is designed to run for 700,000 before a major overhaul.  Cummins Big Cam 855 Engines are typically found in tractor trailers, combines, tractors, harvesters, swathers, seeders, balers, excavators, dozers, compactors, rollers, pavers, loaders, large skid steers / track loaders, large forklifts, motor graders, cranes, dump trucks and more.

Notable aspects of the design is the demand flow cooling system which only cools parts of the engine when needed. This saved energy is this used at the crankshaft to deliver more horsepower to the task at hand. This additional horsepower is what made the engine so popular over the previous smaller cam models. A larger camshaft diameter and larger top stop injectors really pushed up the HP on these engines. Top-Stop Injectors are all mechanical but are designed to using a zero lash setting on the base circle on the cam injector lobe. This zero lash setting became known as the Inner Base Circle or “IBC” and increased fuel flow significantly over the small cam models.

Reaching 400+ HP was now attainable and stable without having to do any performance upgrades to the fuel pump. The drawback to the fuel injection system is the lower 2,200 psi it runs at which negatively affects power to the oil pump, water pump, variable timing system and valve spring pressures. In cold climates the engine can be difficult to start. However this can be remediated with  block heaters or oil immersion heaters. Overall, you’re not going to have a whole lot of issues with this classic diesel engine.

Cummins 855 Specs

Engine Data

Engine Type Four Stroke, Six Cylinder, Inline
Displacement 856 ci (14.0 L)
Bore 5.50 in
Stroke 5.98 in
Compression Ratio 10:1
Max Horsepower 605 HP @ 1800 RPM
Max Torque Ratio 1,118 ft-lbs @1800 RPM
Governed Speed 1800 RPM
Cylinders 6 Inline
Cylinder Head Material Cast Iron
Engine Block Material Cast Iron, Removable Liners
Camshaft Drive Gear Driven
Crankshaft Forged Steel
Fuel System PT Self Adjusting System, Direct Injection
Starting System 24 Volt, negative ground
Emission Abatement Early Versions N/A, Later Tier II, Tier III
Turbo Holset or Aftermarket
Oil System Wet Sump
Oil System Capacity 38.6
Cooling Capacity 45.0 L
Cooling System Water-Cooled
Control System Mechanical
Dry Weight 1,410 lbs.


Give us a call today at 844-340-4114 for immediate sales and support for our Cummins Big Cam Engines for sale, Cummins 4BT, Cummins 6BT, 6CT, ISC, 855, QSB 4.5 L or CAT 3306. If you have any questions check out our FAQ Page. We are always ready to help or just listen to your crazy off-roading adventures!

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Cummins 855 Engines Gallery

855 Big Cam Long Block 1
855 Big Cam Long Block 2
NT855 1
NT855 2
NT855 Engine Assy  1
NT855 Engine Assy  2
NT855 Engine Assy  3
NT855 Engine Assy  4

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