Engine Overhaul of Cummins QSB6.7 in Terex RT 665 Crane

Overhaul of the Cummins QSB6.7 Engine (160 kW) in the Terex RT 665 Rough Terrain Crane

The Terex RT 665 rough terrain crane is a versatile machine designed to operate in demanding off-road conditions, combining mobility with high lifting capacity. The machine is equipped with a Cummins QSB6.7 engine rated at 160 kW, known for its reliability and efficiency in off-highway applications. Our service department specializes in comprehensive overhauls and rebuilding of such power units, providing customers with confidence and operational safety.

The scope of work included engine diagnostics, disassembly, component inspection, regeneration of critical elements, reassembly, and engine dynamometer testing. The decision to carry out the overhaul was made due to a noticeable loss of compression and increased oil consumption, which are typical symptoms of worn cylinders and pistons.

Stages of Work

Engine Removal

The removal of the engine from the Terex RT 665 was carried out using a crane provided by the customer near Katowice. The process included disconnecting all hoses, auxiliary equipment, and components of the cooling and air intake systems. The engine was safely lifted, secured, and transported to our facility in Kojszówka for further inspection and repair. During disassembly, all mountings, fuel and hydraulic lines, and electrical connections were carefully checked to ensure safety and completeness of all components.

Component Inspection

In the workshop, we carried out a full inspection of the crank-piston assembly, including examination of pistons, rings, liners, and crankshaft bearings. We also measured crankshaft runout and assessed connecting rod wear. The cylinder head was tested for tightness and microcracks using a pressure test in a water bath. The fuel system, including the injection pump and injectors, was tested on a calibration bench, while the turbocharger and other auxiliary components were checked for play and wear.

Regeneration and Repair

The repair process included a complete rebuild of the Cummins QSB6.7 engine. In the crank-piston system, worn piston rings, liners, and bearings were replaced, restoring nominal operating parameters. The cylinder head underwent full regeneration – valve guides, valves, and seals were replaced, and all working surfaces were subjected to precise measurements and leak tests. The fuel system was calibrated and tested, while auxiliary components, including the turbocharger, alternator, and starter motor, were inspected and restored to full operational condition.

Engine Installation

Installation of the engine in the Terex RT 665 was carried out in accordance with the highest service standards. Each component was precisely positioned in the machine, with air and fuel lines installed ensuring full tightness. Hydraulic and electrical connections were checked for leaks and proper operation. The engine was started in the presence of the operator, followed by detailed functional tests and monitoring of operating parameters. Particular attention was paid to oil pressure, operating temperature, and turbocharger performance to ensure that the engine delivers full power while maintaining safe operating conditions.

Engine Dynamometer Test

After installation, the engine was tested on our engine dynamometer. The test included a multi-stage load procedure simulating real operating conditions of a rough terrain crane. The Cummins QSB6.7 engine operated for a minimum of 16 hours under light load, after which the load was gradually increased to the nominal level. Thanks to our dynamometer, we were able to precisely measure torque parameters, fuel pressure, and cooling system efficiency, providing the customer with full quality control and confidence in the reliability of the power unit.

Post-Overhaul Engine Operation

After completion of the overhaul and testing, the customer received a full operation and service instruction. We recommend the first filter replacement after 50 engine hours (mth) from initial start-up, followed by inspections every 250 mth or every 3 months, whichever comes first. Our mobile service team can reach customers in the Katowice area to carry out these inspections, checking the tightness of connections, auxiliary equipment operation, and monitoring for any leaks, ensuring long-term reliability of the crane.

Information About Machines Using This Engine

The Cummins QSB6.7 engine with an output of 160 kW is used in a wide range of off-highway machines, including rough terrain cranes, wheel loaders, and material handling excavators. Its reliability and performance make it a popular choice in machines requiring high power output in demanding terrain conditions.