QSK78 (Tier 4 Final/Stage IV)

Certification Tier 4 Final / Stage IV


Mining Engines


Whether you are mining copper in the Andes or oil sand in Alberta, the Cummins QSK78 Tier 4 Final engine provides the optimal combination of productivity and performance in the world's largest class of haul trucks. Its 3500-horsepower (2610 kW) V18 configuration incorporates improved features from our QSK 78 Tier 2 engine, including advanced combustion technology, simplified serviceability of the thermostat and cooling circuit, double oil filter and lube oil life resulting from cleaner combustion and added improvements, as well as a 10 % increase in fuel burn to overhaul.

With more than 1 million hours in operation, we have utilized our innovative technology expertise to optimize the engine and HHP Tier 4Systems; thus, lowering your total operating costs, and increasing the reliability and durability on our Tier 4 Final engine Series. In addition, in comparison to the QSK78 Tier 2 engine, we have increased the QSK78 Tier 4 Final engine’s reliability by increasing the robustness of the gear train, connecting rod, and cylinder head.

Every QSK78 Tier 4 Final engine is covered by Cummins base warranty, one of the most comprehensive and simplest plans in the industry.

  • One-Piece Cast-Iron Block - designed to absorb dynamic internal forces. Wide cylinder spacing allows for multiple full-life overhauls.
  • Heavy-Duty Front Gear Train - A modification of the proven QSK60 design that has low gear loading and high fatigue strength for dependable service.
  • Forged High-Strength Tensile Steel Crankshaft - Combined with dual viscous dampers reduces gear train wear. Tungsten counterweights provide vibration damping for long engine and equipment life.
  • Quantum System Electronics - High-speed Electronic Control Module (ECM) is isolated from detrimental vibration loading. A field-proven, fully-sealed wiring harness with fail-safe connectors integrates the ECM with the engine sensors for optimized engine performance, monitoring and protection. Quantum system technology is ideal for tough mining applications that demand continuous uptime carrying hundreds of tons capacity.
  • Fuel system – The Cummins Modular Common Rail Fuel System (MCRS) gives a 10% increase in fuel burn to overhaul and larger injector accumulator volume, for reduced PM and improved fuel economy. The leakless injector has increased fueling precision and timing control, for reduced parasitic losses, reduced fuel heating and improved fuel economy. The fuel pump has an improved tappet design and fuel cooling of pumping elements, which contribute to longer component life. In addition, the MCRS fuel system on this engine has been designed to provide constant high-injection pressure regardless of engine speed, for improved brake thermal efficiency and engine responsiveness with higher productivity’ while also delivering lower noise and vibration for increased operator comfort meeting noise regulations.
  • Two-stage Holset® Turbocharging from Cummins Turbo Technologies - Delivers full power and exceptional fuel efficiency at up to an industry-leading 12,000 ft. (3,658 meters) altitude without derate.
  • Wiring - Safely enclosed inside a foam-filled extruded aluminum channel and is completely sealed from the external environment to prevent chafing and corrosion damage. DIN-style connections have a locking feature that protects against pin-fretting damage.
  • Prelub™ System - Distributes oil to rifles and friction surfaces and builds oil pressure before cranking can occur, reducing engine wear and greatly extending life-to-rebuild.
  • ELIMINATOR™ - Self-cleaning filtration system comes standard and combines full-flow and bypass filters with an oil-pressure-powered centrifuge. Stainless steel filter screens trap particles as small as 20 microns; centrifuge removes particles as small as 2 microns.
  • Cylinder Head- Optimally designed for improved coolant flow load distribution and stiffness. In addition, the material used on our Genuine Cummins cylinder head reduces corrosion and gasket fretting, while also improving its hardness and durability and longevity.
  • Connecting Rod- Parented from the QSK60 and QSK95 engines, both ends of the connecting rod have been modified and improved to provide the smoothest, most durable surface. As part of the geometrical optimization on the big end of this part, meticulous engineering was applied on the increase of the bore stiffness as well as on the inclusion of enhanced bolts. The small end of the rod displays an increased bush width, revised oil groove geometry and an offset oil hole.
  • LT and HT Thermostat- Thermostats have been precisely designed to ensure better serviceability access. Additionally, the LT circuit joint has been removed from V-cavity, hence simplifying the HT and LT coolant line routing.

To access our complete brochure library, click here.
Redirecting to

The information you are looking for is on

We are launching that site for you now.

Thank you.