Renovation of the Liebherr D9406 TI-E A3 Engine in the LR 1400/2 Crawler Crane

Introduction

A lattice crawler crane Liebherr LR 1400/2 equipped with a diesel engine Liebherr D9406 TI-E A3 has arrived at our service. This machine is used for large construction investments, including the assembly of steel structures and work on industrial facilities. The manufacturer Liebherr is one of the largest suppliers of lifting equipment in the world, and its power units are characterized by durability and power adapted to demanding conditions.

The Liebherr D9406 TI-E A3 engine, a six-cylinder turbocharged diesel, is known for its high reliability; however, after many thousands of operating hours, a major overhaul became necessary. The reason for the repair was burnt valves and starting problems. During the initial diagnostics, the operator reported a loss of power and uneven operation, which was confirmed by our cylinder leak tests and compression measurements.

Engine Disassembly

We performed the engine disassembly at the construction site near Katowice. The client provided us with a service crane, allowing us to safely remove the power unit from the crane frame. Our mechanics disconnected all fuel, cooling, and electrical lines, as well as auxiliary components such as the turbocharger and alternator. An important step was securing the cooling system and air intake to prevent contamination of the components during transport. After proper preparation, the engine was loaded and transported to our headquarters in Kojszówka.

Verification of Components

On-site in the workshop, we began a detailed verification of the engine. The diagnosis regarding the damaged valves was confirmed – some of them were burnt, and the seats required machining. We also checked the crank-piston system: the crankshaft showed no excessive wear, but the bearings and piston rings needed replacement. The cylinder head underwent a pressure test, during which we checked the tightness of the water channels. The fuel injection pump was also verified on the test bench, along with the turbocharger and starter. All results were recorded in the verification protocol.

Regeneration and Repair

Crank-Piston System

We replaced the cylinder liners, pistons, and rings. The main and connecting rod bearings were replaced with new ones. The crankshaft underwent measurements and grinding to nominal size. We checked the connecting rods for twisting and bending, and then selected a weight-matched set.

Engine Head

The head was planed, and we replaced the valve guides and valves. The leak test confirmed proper sealing. As a result, the head is fully prepared for further operation.

Fuel System

The fuel injection pump was sent to an authorized facility, where it underwent regeneration and calibration. The injectors were replaced with regenerated ones with factory parameters. The supply pump was also replaced with a new one.

Auxiliary Equipment

The turbocharger underwent regeneration with the replacement of bearings and seals. The alternator and starter were tested and serviced. All hoses and rubber connections were replaced with new ones to avoid issues during further operation.

Engine Assembly

After the repair was completed, we proceeded with the assembly. The engine was mounted in the crane frame following all manufacturer standards. We installed new air and cooling lines, checked the tightness of the entire system. We replaced the filters and oil, and then conducted a trial start. In the presence of the operator, we performed load tests to check the engine's cooperation with the other components of the machine. After several hours of testing, we signed the assembly acceptance protocol.

Engine Test on the Dynamometer

WIBAKO, as one of the few companies in Poland, has its own engine dynamometer. The Liebherr D9406 TI-E A3 engine was tested in full operating range before assembly. For 16 hours, it operated under partial load, allowing us to check oil pressure, coolant temperature, and cylinder uniformity. The next stage involved multiple tests under loads close to nominal to confirm the power and torque of the unit. These tests allow us to avoid situations where the client would have to stop the machine after assembly due to oversights. Thanks to the dynamometer, we are confident that every repaired engine leaves our facility 100% functional and ready for work.

Engine Maintenance After Overhaul

Every engine after an overhaul receives a warranty. We recommend the first filter change and connection check after 50 operating hours. Our mobile service arrives at the machine's work site and performs a full inspection. Subsequent inspections are scheduled every 250 operating hours, but no less than once every three months. Such maintenance allows extending the unit's lifespan and ensuring trouble-free operation.

Machines with Liebherr D9406 TI-E A3 Engine

The Liebherr D9406 TI-E A3 engine is used not only in Liebherr LR 1400/2 lattice crawler cranes but also in other Liebherr construction machines, including some models of mobile cranes and specialized equipment used on large industrial construction sites.

Summary

The overhaul of the Liebherr D9406 TI-E A3 engine in the Liebherr LR 1400/2 lattice crawler crane was a complete success. Thanks to professional verification, regeneration, and dynamometer tests, the client received a machine ready for intensive work. The use of new parts, attention to detail during assembly, and the support of WIBAKO's mobile service guarantee trouble-free operation and extended engine lifespan.