Introduction

The Liebherr LTM 1040/1 mobile crane is a proven design in the mobile crane segment, valued for its versatility and reliability in construction and industrial work. In this case, our service received a unit equipped with a Liebherr D926 TI diesel engine with a power output of 230 kW. Engines of this series are known for their durability and high operational culture; however, intensive use means that after a certain mileage, they require a thorough overhaul. The unit was delivered to our service in Kojszówka from the vicinity of Katowice, where we performed the engine disassembly with the help of a crane provided by the client. The reason for sending the engine for repair was issues with cylinder and piston wear, which manifested as a drop in compression, increased smoking, and excessive oil consumption.

Preliminary diagnostics were carried out on-site in the machine, where we checked the compression pressure and performed an endoscopy of the cylinders. The results confirmed the need for disassembly and a full verification of the engine in our workshop. Below we present the stages of the service work performed.

Engine Disassembly

The disassembly process began with disconnecting the cooling system, air intake, and electrical installation. All hoses, clamps, and accessory components were secured to avoid damage. The client provided a crane, which made it possible to safely remove the power unit from the crane frame. After securing it, the engine was transported to our headquarters in Kojszówka, where it underwent detailed verification.

Verification of Components

The Liebherr D926 TI engine was disassembled into its basic components. According to the preliminary diagnosis, we found significant wear on the cylinders, pistons, and rings, which caused a drop in sealing and compression. Additionally, we checked:

  • crankshaft – measurements of the journals were taken and oil channels were checked,
  • connecting rods – measurements of twisting and visual inspection were conducted,
  • cylinder head – subjected to a leak test in a water bath using compressed air,
  • turbocharger – axial and radial play were examined,
  • fuel injection pump – sent to an external facility for testing on a test bench.

Regeneration and Repair

Crankshaft-Piston System

Worn pistons were replaced with new ones, and the cylinders were machined and sleeved. The crankshaft was ground and mounted on new bearings. All components were assembled while maintaining factory tolerances.

Engine Head

The head underwent complete regeneration: machining, replacement of valve guides, and valves. The leak test confirmed the absence of micro-cracks and the possibility of further operation.

Fuel System

The fuel injection pump was regenerated at a specialized facility, while the injectors were calibrated and tested on a test bench. This restored the correct fuel atomization and uniform operation of the unit.

Accessories

The turbocharger, starter, and alternator were also regenerated. All components were checked for performance and sealing to avoid operational issues in the future.

Engine Installation

Installing the engine in the LTM 1040/1 mobile crane is a process that requires precision and experience. The unit was installed in the vehicle frame, and then the cooling system, air intake, exhaust, fuel, and electrical systems were connected. All connections were checked for sealing and proper operation. We also replaced the complete set of filters and rubber hoses in the cooling and intake systems to ensure reliability for many years.

After installation, we conducted preliminary tests of the machine's operation together with the crane operator. We checked for leaks, stability of operation at various RPMs, and response to load. After a positive result, an acceptance protocol for the installation was signed.

Engine Test on the Dynamometer

One of our greatest assets is our own engine dynamometer, where we test all units after repair. The Liebherr D926 TI engine was started and subjected to testing for a minimum of 16 hours under light load, and then repeatedly loaded to nominal values. This allowed us to check its operating parameters, including oil pressure, temperature, fuel consumption, and effective power.

The dynamometer allows us to simulate real working conditions of the machine, eliminating the risk of unforeseen failures after installation. This gives the client assurance that they receive an engine that is fully tested and ready for further intensive operation. Such tests guarantee quality and safety – few service companies in Poland have such advanced technical facilities.

Engine Maintenance After Repair

Every engine after repair is covered by a warranty. We recommend changing filters and checking connections after the first 50 operating hours. Our mobile service visits the client to conduct this inspection. Subsequent checks should be performed every 250 operating hours, but no less frequently than once every three months.

Application of the Liebherr D926 TI Engine

The Liebherr D926 TI engine with a power output of 230 kW is used not only in Liebherr LTM series mobile cranes but also in other construction and handling machines from this manufacturer. Due to its design and high power, it is widely used in equipment requiring high reliability and long service life.

Summary

The overhaul of the Liebherr D926 TI engine in the LTM 1040/1 mobile crane was a complete success. Thanks to the comprehensive regeneration of the crankshaft-piston system, head, fuel system, and accessories, as well as tests on the dynamometer, the client received a fully operational unit ready for work. Our experience, professional approach, and technical facilities allow us to offer Liebherr diesel engine service at the highest level.

We invite you to contact WIBAKO for repairs and service of engines and construction machines. We offer both stationary and mobile service, and our engine dynamometer guarantees reliability after every repair.