Reconstruction of the Liebherr D9508 A7 Engine in the LTM 1300-6.2 Crane

Engine Overhaul of Liebherr D9508 A7 in Mobile Crane LTM 1300-6.2

Introduction

In our company WIBAKO, we had the opportunity to carry out a comprehensive overhaul of the Liebherr D9508 A7 engine with a power of 450 kW, installed in the powerful mobile crane Liebherr LTM 1300-6.2. This machine, known for its impressive load capacity and precision work in the field, came to our service due to a noticeable drop in power and increased oil consumption. The owner also reported difficulties with starting in low temperatures, indicating a compression problem in the cylinders.

The LTM 1300-6.2 model is a mobile crane with a maximum lifting capacity of 300 tons, equipped with a 6x8x10 drive. Its heart is a powerful, 8-cylinder V8 engine Liebherr D9508 A7, also used in other heavy Liebherr machines. As part of the service, we performed a complete disassembly, regeneration, test on the dynamometer, and reassembly of the engine in the machine.

Engine Disassembly

We started the process by disassembling the engine from the crane frame. The operation was carried out with the help of a crane provided by the client. Our mechanics secured the hydraulic lines, fuel connections, air intake, and cooling system. Each component was labeled and prepared for reassembly, which significantly shortened the time for later assembling the power unit. After removing the accessories, the engine was transported to our headquarters in Kojszówka.

Verification of Components

During the verification, the assumption of cylinder and piston wear was confirmed. Compression pressure measurements and leak tests clearly indicated a leak in several cylinders. The disassembly of the engine also allowed for a thorough examination of the crankshaft, cylinder heads, and fuel system. The turbocharger, fuel pump, and injectors were also subjected to verification.

Regeneration and Repair

Crankshaft-Piston System

All cylinder liners were replaced with new ones, and the pistons with rings were matched according to the manufacturer's recommendations. The crankshaft was ground and regenerated, and the connecting rods were geometrically inspected. New main and connecting rod bearings were installed.

Engine Head

The heads underwent complete regeneration – machining, replacement of valve guides and valves, followed by a leak test in a water bath. After successful tests, the heads were mounted on the engine with new gaskets and bolts according to the tightening torques recommended by Liebherr.

Fuel System and Accessories

The fuel pump was checked on the test bench and calibrated. The injectors were ultrasonically cleaned and their tips were replaced. The turbocharger was regenerated – axial play, balancing, and system tightness were checked. The alternator and starter were also tested and serviced.

Engine Assembly

After the regeneration, the engine was assembled in workshop conditions while maintaining full cleanliness of the assembly. Each component – from fuel lines to the cooling system – was thoroughly checked and installed with new seals. Before mounting in the crane, an oil pressure test and a leak test of all connections were performed.

The engine was then returned to the LTM 1300-6.2 crane, where our team precisely positioned the power unit. During assembly, the air piping, cooling lines, and mounting elements were replaced. The machine was started in the presence of the operator, monitoring temperature, oil pressure, and operating parameters. After successful tests, a handover protocol was signed.

Engine Test on the Dynamometer

All engines after overhaul at WIBAKO undergo testing on our dynamometer. The D9508 A7 unit was tested for 18 hours – first under light load, and then under full nominal load. We monitored oil pressure, coolant and exhaust temperatures, cylinder uniformity, and fuel consumption. The dynamometer allows us to simulate real operating conditions and eliminate any irregularities before installation in the machine.

The test confirmed the correct operation of all systems and stability of parameters under full load. As a result, the client received a fully functional engine ready for further operation without the risk of failure.

Engine Maintenance After Overhaul

After the overhaul, we recommend the first oil and filter change after 50 operating hours, followed by regular inspections every 250 operating hours or every 3 months. Our mobile service WIBAKO performs inspections at the client's site, ensuring the continued reliability of the machine.

Machines Featuring the Liebherr D9508 A7 Engine

The Liebherr D9508 A7 engine is found not only in the LTM 1300-6.2 cranes but also in other Liebherr machines such as the LTM 1250-5.1, LTM 1350-6.1, and LTM 1400. It is a unit valued for its high work culture, torque, and durability in harsh operating conditions.

Summary

The overhaul of the Liebherr D9508 A7 engine in the LTM 1300-6.2 crane was carried out comprehensively – from diagnostics, through regeneration, to testing on the dynamometer and installation in the machine. Thanks to our experience and technical background, the engine was restored to full efficiency. The client gained reliability, operational certainty, and a quality guarantee confirmed by dynamometer tests from WIBAKO.

We invite you to contact us – we offer overhauls, repairs, and servicing of Liebherr engines and other brands for construction machines throughout Poland and abroad.