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Replacement Cummins 6CT Engines for Sale

Replacement Cummins 6CT Engines For Sale

These hard-working engines go by a number of different names, but whether you call it the Cummins 6CT, the 8.3L Cummins, or (for the later, electronically controlled version) the Cummins ISC, you’re talking about the same thing: a powerful workhorse that can be used in a variety of applications. Whether you need an 8.3L 6CT Cummins to power a bus, an excavator, a crane, or something else entirely, these 8.3L engines are a sound option with a reputation for durability.

At Big Bear Engine Company, we’re proud to offer two different replacement options for your Cummins 6CT 8.3L: Standard Long Blocks and more complete Extended Long Blocks.

Our 6CT 8.3L Component Build Program Entails:
6CT 215hp

  • 8.3L component build assemblies
  • Built with OEM and aftermarket parts
  • Extended Long Block Power Ratings: 215 hp, 240 hp, 260 hp, or 300 hp
  • Standard Long Blocks (1/2 to 3/4 assemblies)
  • Standard 12-month parts replacement warranty
  • 1- or 2-Year Parts/Labor Extended Warranties Available
  • All Extended Long Blocks are run-tested before shipping
  • No core charge
  • Same day shipping
  • Financing available

Big Bear Cummins 6CT Long Block

If you've recently replaced or have adequately working parts from an existing engine on your Cummins 6CT and don’t want to spend the money on a completely new assembly, our Standard Long Block option is ideal for your situation. Our Standard Long Block will replace the worn-out internal parts of the engine (such as the cylinder head, crankshaft, and connecting rods, among other things) without requiring you to purchase parts you don’t need. You’ll be left with a high-quality solution that was extremely cost-effective to put together.

As a guide, a standard long block assembly is about 50 percent to 75 percent of a complete build. Think of the "guts of the engine," but nothing in the way of dressing it out.

6CT Long Block Castings Include:6CT 215hp

  • Block
  • Cylinder Head
  • Camshaft
  • Camshaft Gear
  • Followers and Lifters
  • Pistons
  • Piston Rings
  • Gaskets
  • Bearings
  • Plugs and Bolts
  • Push rods
  • Connecting Rods
  • Front Cover
  • Timed Front Gear Train Group
  • Crankshaft
  • Oil Pump
  • Oil Cooler
  • Freeze Plugs and Block Plugs
  • Front Rear and Main Seal
  • Valve Cover
  • Oil Pickup Tube
  • Front Sump Oil Pan
  • 1 or 2 Thermostat Block Applications
  • Outright Pricing (No Core Charge)
  • Long Block Does not include Fuel Lines, Fuel Pump, Turbo, Injectors
  • Standard 12 Months Parts Replacement Warranty
  • 1 or 2 Year Parts/Labor Extended Warranties Available

6CT Extended Long Blocks

For those looking for an alternative to their current engine, or that want something new, our 6CT complete engines are the answer.

Our Extended Long Block option comes with a complete fuel system, turbo, and exhaust manifold installed, nearly everything you need to re-power your piece of equipment. When you choose a Big Bear Extended Long Block, you can trust that all of the parts are brand new and have been tested for quality to rule out any risk of failure. On top of that, all of our Extended Long Blocks are test-run prior to shipping. This ensures that each 6CT is 100-percent ready to go when it shows up at your door.

As a general guide a component build 6CT assembly is roughly 90 percent brand new OEM parts and 10 percent aftermarket components, when available. These units are perfect for the customer looking to replace an existing 6CT Cummins assembly but that also needs a new turbo or oil pump, etc...  In most cases, an extended long block is about 75 perecnt built out and is best used in conjunction with an existing 6CT 8.3L unit.

Extended Long Blocks Include:

  • AERA Association MemberBlock
  • Cylinder Head
  • Camshaft and Lifters
  • Connecting Rods
  • Pistons and Rings
  • Gaskets and Bearings
  • Plugs and Bolts
  • Push rods
  • Rocker Assemblies
  • Injectors
  • Inline Fuel Pump
  • Connecting Rods
  • Crankshaft
  • Turbocharger
  • Aftercooler (215 hp, 240 hp is Jackwater Aftercooled ‘JWAC’, 260 hp, 300 hp Air-to-Air Intercooler Setup)
  • Vibration Damper
  • Water Pump
  • Oil Pump
  • Oil Cooler
  • Accessory Drive Pulley
  • Air Cross Over Tube
  • Accessory Drives
  • Inlet and Outlet Connection
  • Throttle Lever
  • Oil Pan and Pickup Tube
  • 1 or 2 Thermostat and Block Applications
  • No Core Charge
  • 12 Month Parts Replacement Warranty
  • 1 or 2 Year Parts/Labor Extended Warranty Available


Note: Extended Long Block do not include a starter, alternator, flywheel, ring gear, flywheel housing, radiator, hoses or additional air cross over tubes, throttle linkage, air charge cooler (260, 300 hp) , thermostat housing, water outlet connection, fan support, alternator mount, belt tensioner and bracket, air compressor, shut down solenoid


  • 6CTA – 215 hp (Industrial Rating built to CPL 722)
  • 6CTA – 240 hp (Automotive or Industrial “Non-Road” Rating, built to CPL 8765)
  • 6CTAA – 260 hp (Automotive Rating built to CPL 303)
  • 6CTAA – 300 hp (Automotive Rating built to CPL 333)

Note: Cummins 6CT assemblies are versatile in their governed rated application meaning an automotive spec can be used in an industrial application and vice versa. We have seen all assemblies used and swapped in a variety of applications. We will work with you to determine the best fit based on your application but ultimately it is up to you to determine the best use of the assembly required to meet your needs.

Cummins 6CT Engine Applications

Cummins first began producing these engines in the late 1980', and there is a reason they're still so popular today. As you might imagine, there are a wide range of industrial and automotive applications for Cummins 6CT engines, but here are some of the most popular:

  • Construction — The fuel efficiency and compact size of Cummins 6CT engines makes them a cost-effective and low-maintenance solution for construction applications. The replaceable cylinder liner design contributes to long-term durability and convenient in-field serviceability (when necessary), and the cold start capabilities also make these engines desirable for construction crews who need to work regardless of the weather conditions.
  • Buses — Many of the same factors that make Cummins 6CT engines appealing for construction also make them ideal for busses of all types. Because buses are responsible for transporting so many passengers, it’s crucial that they use a reliable engine.
  • Trucks — Cummins 6CT and later version electronic ISC engines are popular for medium-duty trucks of all sorts as they are powerful enough to complete a fair amount of hauling, but are also reliable enough to get the job done without incident.
  • Industrial - The 6CT has been used in a multitude of applications from material handling, forestry, mining, rail, cranes, pumps, stationary power, marine, you name it and we’ve probably got a build for it!

Cummins 6CT engines have an incredibly wide range of applications, and it’s no wonder why these power plants have become so popular in so many different industries.

Cummins 6CT Spec

Engine Data

ConfigurationInline-six Cylinder, Four-stroke
Displacement8.3L (504.5 ci)
Bore x Stroke4.49 inches x 5.32 inches
Cylinder HeadCast Iron
Engine BlockCast Iron
Firing Order1-5-3-6-2-4
Compression Ratio17.5 : 1
InjectionDirect Injection, Mechanical Injection Pump
AspirationTurbocharged, wastegate controlled
Valve TrainOHV, 2 valves per cylinder (ISC/QSC have a 4-valve design)
Weight1,512 lbs dry, depending on model
Oil Capacity20 quarts
Governor SpeedVaries with application
Horsepower215 hp to 300 hp, Extended Long Blocks
Torque660 lb-ft to 1200 lb-ft, depending on model


Give us a call today at 844-340-4114 for immediate sales and support for the 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 6CT Engines Gallery

Cummins 6CT
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Cummins 6CT Long Block 1
6CT 260HP Extended Long Block D
Cummins 6CT Engine

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