Repair of Liebherr D9508 A7 Engine in LTM 1450-8.1 Crane

Engine overhaul Liebherr D9508 A7 in Liebherr LTM 1450-8.1 mobile crane

Introduction

At our headquarters in Kojszówka, we carried out a comprehensive overhaul of the Liebherr D9508 A7 engine with a power of 505 kW, installed in the powerful Liebherr LTM 1450-8.1 mobile crane. This impressive all-terrain crane combines immense power with mobility, allowing it to operate in challenging terrain and construction sites. The client approached us after noticing a drop in power and uneven operation of the engine. Liebherr is known for its precision engineering and durability, but even these constructions require servicing after many thousands of operating hours.

The Liebherr D9508 A7 engine is an eight-cylinder unit in a V configuration, designed for use in heavy machinery, including mobile cranes and specialized machines. It is characterized by high torque and a robust fuel system. In this article, we present a detailed account of the repair work that restored the full functionality of this engine.

Cause of the overhaul and preliminary diagnostics

The reason for the repair turned out to be worn crankshaft bearings and connecting rods, which manifested as metallic knocking sounds and a drop in oil pressure. Our mobile service team arrived at the crane's work site near Katowice, where preliminary oil pressure measurements, filter analysis, and an oil sample for laboratory testing were conducted. The presence of metal particles in the oil filter confirmed initial suspicions of bearing wear. After performing an endoscopic inspection and pressure measurements, the necessity of disassembling the engine was confirmed.

Engine disassembly from the Liebherr LTM 1450-8.1 crane

The engine disassembly was carried out using a crane provided by the client. Our technicians removed the engine accessories, hydraulic hoses, cooling system, and air intake piping. All components were secured and labeled to facilitate the reassembly process after the overhaul was completed. After disconnecting the engine unit, the engine was transported to our workshop in Kojszówka, where a detailed technical verification began.

Verification and diagnosis in the workshop

The verification confirmed significant wear of the crank-piston system. The bearings were worn, and the crankshaft showed signs of overheating. Additionally, play was diagnosed in the cylinder liners and minor leaks in the head assembly. The cylinder head underwent a leak test in a water bath using compressed air – with no cracks detected. The crankshaft was sent for measurements and regeneration, while the connecting rods were checked for straightness and weight.

Regeneration and repair

Crank-piston system

As part of the repair, all main and connecting rod bearings, cylinder liners, pistons, and rings were replaced. The crankshaft was ground and regenerated according to Liebherr's factory tolerances. The connecting rods underwent a full inspection and replacement of fastening bolts.

Engine head

The head was planed, guides and valves were replaced, and the valve seats were lapped. The entire assembly underwent a leak test and valve pressure check.

Fuel system and accessories

The injection pump was regenerated at an external facility, and the injectors were tested on a test bench. The turbocharger was checked for axial and radial play, while the alternator and starter underwent servicing.

Test on the engine dynamometer

After assembling the Liebherr D9508 A7 engine, it underwent several hours of testing on our modern engine dynamometer. The tests began with a 16-hour work cycle at 25% load, during which the coolant temperature, oil pressure, RPM stability, and fuel consumption were monitored. After a positive assessment of the preliminary results, the engine was gradually loaded up to 100% of its rated power. Our dynamometer allows for the simulation of real working conditions, ensuring that every engine leaving our facility is fully verified. Final measurements confirmed the achievement of full power of 505 kW and stable operation across the entire RPM range.

Engine installation in the crane

After successfully passing the dynamometer tests, the engine was prepared for installation in the Liebherr LTM 1450-8.1 crane. Our mobile team performed the installation at the machine's work site near Katowice. The installation included carefully inserting the engine unit into the machine frame, replacing the air and coolant piping, and connecting hydraulic and electrical lines. After completing the installation, leak tests of the connections and startup were conducted in the presence of the crane operator. Following a series of operational tests, a handover protocol was signed, confirming the proper operation of the engine.

Engine maintenance after the overhaul

Every engine after an overhaul at WIBAKO is covered by a warranty and full service support. We recommend performing the first inspection after 50 operating hours – including filter replacement, leak checks, and analysis of operating parameters. Subsequent inspections should occur every 250 operating hours or at least every three months. Our mobile service team carries out these inspections directly at the client's location, minimizing machine downtime.

Application of the Liebherr D9508 A7 engine

The Liebherr D9508 A7 engine is used not only in mobile cranes but also in crawler cranes, technological dumpers, and large Liebherr loading machines. Due to its high power and reliability, it is often used in machines with high lifting capacity, where a combination of power and precision is required.

Summary

The overhaul of the Liebherr D9508 A7 engine in the Liebherr LTM 1450-8.1 mobile crane was carried out comprehensively – from diagnostics to dynamometer tests. Thanks to the precision of our specialists and modern technical facilities, the engine regained full functionality and readiness for years of operation. The client received a warranty, documentation from the dynamometer tests, and service recommendations, ensuring the safety and reliability of the crane's operation in all conditions.

We invite you to contact WIBAKO for Liebherr engine overhauls and comprehensive construction machinery service. Our experience and technological background allow for effective engine repairs for brands such as Liebherr, Cummins, Deutz, Volvo, Perkins, and Scania.