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Cummins QSB and ISB 4.5 L Engine Program

Cummins QSB and ISB 4.5 L Engines for Sale:

The QSB and ISB 4.5 L engine from Cummins is the cousin of the famed 4BT (3.9 L) engine. Although, very similar these two engines differ in a few different ways. The 4.5 L Cummins engine comes as a QSB or ISB varieties. “QSB” stands for off-road applications where as an “ISB” engine is usually on-road.

Cummins QSB 4.5 L Engine Surplus UnitCummins ISB / QSB 4.5 L engines can be either front or rear gear train. Most vehicle applications (mostly Dodge) contain front gear train engines. Many industrial applications like skid steers, tractors, wood chippers, excavators and the like have rear gear train setups. However, you have to be careful as many industrial applications will have front gear train setups as well. There is no hard and fast rule with the 4.5 L engines.

Other misconceptions between the 4BT 3.9 L and 4.5 L are that the engine blocks and cylinder heads are the same which is untrue. The 4.5 L engines come in many different varieties all with different block sizes and part number supersessions throughout the years.

Many customers claim they have an old mechanical 4.5 L when in fact they are mistaken. All QSB 4.5 and ISB 4.5 engines are electronically controlled. The fuel systems all use the High Pressure Common Rail Fuel System (HPCR). Usually you’ll see VP44 Fuel Pumps in those units from manufacturers such as Bosch, Lucas, or Stanadyne.

We build custom solutions for the 4.5 L engines vs. having surplus stock engines. The configurations are such that having a “one size fits all” solution isn't practical for most customers. If you have a QSB 4.5 L engine that has a rod though the block or dropped a valve and needs to be replaced, we have the ability to custom manufacturer one back to your original engine serial number and CPL.

QSB 4.5 L Case Dozer

Cummins QSB 4.5 L in a Case Dozer

The 4.5 L Replacement Engine Process:

1) You provide us with the ESN and CPL
2) You give us as much information to the application as possible
3) You provide us with multiple pictures around the engine to determine how it is dressed
4) Engines are custom manufactured and run tested
5) Engines are shipped with other build cycles

We often see 3rd party packagers with 3.9 and 4.5 engines from Cummins but with no specific engine serial number present. This is common with Case, International Harvester, New Holland, KCB and Komatsu equipment. Cummins had partnerships with those companies to install their engines in other companies’ equipment. These 3rd parties rebranded the engines using their own ESNs. When this happens, we are unable to look up information on a Case or Komatsu engine.

CASE 4.5 L Engine Dataplate

CASE/Cummins 4.5 L Engine Dataplate

If this happens, we recommend calling your OEM to determine overall fit (fuel pump, oil pan sump, turbocharger location and flywheel housing size). It is also very important to know the block dimensions and how it is dressed.

Typical sizes of the QSB 4.5 L engines are 32.2” x 28.1” x 34.5” with a dry weight of 750 lbs and 817 with oil/fluids. Note each unit is different and measurements are approximate estimates based upon Tier II engine data. Tier III and IV engines are larger due to bigger blocks, and ancillary emissions equipment.

In cases where the ESN cannot be obtained, we have the ability to manufacturer QSB engines back to a few common engine serial numbers. Ultimately, it is up to you the customer to determine fit of an engine into your application.

Common Front Gear Train QSB 4.5 ESNs we build to are:
ESN: 30689695 CPL: 8401
ESN: 720111544
ESN: 46376515

QSB and ISB 4.5 L Long Blocks for Sale:

ISB 4.5 Long Block


• Block
• Cylinder Head
• Camshaft and Lifters
• Crankshaft
• Connecting Rods
• Rocker Assemblies
• Gaskets, Rings, Seals, Bearings
• Timed Front Gear Group
• Oil Pan and Pickup Tube
• Standard 12 Months Parts Replacement Warranty
• 1 and 2 Year Parts/Labor Extended Warranties also Available

Note: Long blocks with sometimes come with the front cover and gear housing already configured to your specific fuel pump. Other times, you will have to reuse your old gear housing and front cover off of the old engine.

QSB and ISB 4.5 L Extended Long Block Engines for Sale:

Our replacement extended long block 4.5 L ISB or QSB engines are built back to your ESN and CPL. Extended long blocks are roughly a 75% finished assembly built with 90% OEM parts and 10% when available. That being said variations might existing between each engine. A general guide is that replacements will include the fuel system, turbocharger (N/A if naturally aspirated) and oil pan. Usually customers will reuse starters, alternators, flywheels, flywheel housings (SAE #1, #2 or #3) as they are least likely to be damaged during an engine failure. Engines do not come with wiring harnesses, power steering or vacuum pumps, motor mounts, or transmission adapter plates. Note we also have the ability to build QSB 4.5 L Power Units with the muffler, radiator, control panel if needed. ECM’s are programmed before they are shipped if the customer has the ECM code number and/or part number. Each configuration is different but most QSB or ISB 4.5 L Extended Long Block Engines Come With:

• Block
• Cylinder Head
• Camshaft and Lifters
• Crankshaft
• Connecting Rods
• Rocker Assemblies
• Gaskets, Liners, Rings, Seals, Wrist Pins, Bearings
• Injectors
• Oil Cooler
• Oil Filters
• Intake and Exhaust Manifolds
• Housings (Front and Rear)
• Brackets and Pullys
• Fuel Injector Pump
• ECM (Programmed if Customer Has ECM Code)
• Turbo
• Oil Pan and Pickup Tube
• Standard 12 Months Parts Replacement Warranty
• 1 and 2 Year Parts/Labor Extended Warranties also Available

Cummins 4.5 L Specs

Engine Data

Configuration Inline 4 Cylinder
Displacement 4.5 L, 275 cubic inches
Bore x Stroke 4.02" x 4.39"
Cylinder Head Cast Iron
Engine Block Cast Iron
Emissions Rating Tier II-IV
Compression Ratio 17.2:1
Injection Direct Injection, High Pressure Common Rail
Aspiration Holset Turbocharged, Intercooled
Valve Train OHV, 2 valves per cylinder
Weight 817 lbs. Dry
Cooling Capacity 11.6 quarts oil, 9 quarts of coolant
Governor Speed Varies with application
Horsepower 110 -170 HP @ 2500 rpm
Torque 360 -459 lb-ft @ 1500 rpm
Give us a call today at 844-340-4114 for immediate sales and support for the Cummins 4.5L , Cummins 6BT 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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