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The Technical Specifications for a Cummins QSB 4.5 Liter Diesel Engine

by Justin Cupler

Cummins offers engines for all types of vehicles. The Cummins QSB 4.5 diesel engine, which Cummins classifies as an agricultural engine, has a design most useful in heavy machinery. Cummins produced many different versions of the QSB 4.5 and each one has its own rating, giving it a wide array of possible uses. The QSB 4.5 has three tiers: Tier 2, Tier 3 and Tier 4. Though structurally the same, the output ratings do change from tier to tier.


This engine has four cylinders in a straight line and is known as an inline four-cylinder (I-4). The QSB 4.5 has a bore of 4.02 inches and a stroke of 5.39 inches. The Cummins QSB 4.5 engine has a total displacement of 275 cubic inches, or 4.5 liters. It uses a single turbocharger to add to its power.


The Tier 2 produces 110 horsepower and 305 pound-feet of torque. The Tier 3 engine produces 110 to160 horsepower, depending on options selected, and 460 pound-feet of torque. The fourth Tier version of the Cummins QSB 4.5 produces 110 to160 horsepower and 347 to 460 pound-feet of torque.


These engines have specific capacities for both oil and engine coolant. The QSB 4.5 can hold up to 9 quarts of engine coolant and 11.6 quarts of engine oil.


Being designed to be used in multiple applications, sizing of the QSB 4.5 becomes important. It has a length of 32.2 inches, width of 28.1 inches, 34.5 inch height and a weight of 818 lbs., with all fluids filled.

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