BMW M5 In Depth - Part 2

Press Release

(BMW M5 In Depth - Part 1)

The BMW M5 engine production: Engine construction at its best

The highlights:

• Highly flexible production line with a wide range of products at the BMW Plant in Munich,
• Qualified staff and flexible processes,
• Quality assurance by means of data transfer,
• The highest quality standards.

The 507 bhp high-performance powerplant featured in the new BMW M5 perfectly reflects the manufacturing excellence of the BMW specialists. The production of the most powerful production car engine in the company's history is a complex process which requires premium quality.

Core components from the production network.

The cylinder heads and the crankcase for the new V10 engine are produced at the light alloy foundry at BMW's Landshut plant, which also produces parts and components for the BMW Formula 1 engines.

Due to the heavy strain on the high-revving aggregate, demands on the surface quality and the manufacturing tolerances are extremely high in mechanical processing at the BMW plant in Munich. For example, components are processed at an accuracy of up to 1∕1000 millimetres. By comparison: a human hair is 0.05 millimetres in diameter (50∕1000).

Flexible assembly.

Final assembly, a highly flexible process, is performed in a two-shift pattern in the so-called special-purpose engine department of the Munich plant, where, in addition to the V10 engine, they also produce the six-cylinder aggregate for the M3, the V8 diesel and the twelve-cylinder for the BMW 7 model series.

This diversity calls for a great deal of flexibility, profound product knowledge and excellent skills. This is why the staff responsible for BMW engine construction are all well-trained and experienced.

As this engine is not a high-volume product, full automation of the assembly processes only makes sense to a certain limited extent. This is why operations carried out manually and automated assembly processes are combined to complement each other perfectly.

An ergonomic work environment, devices for pivoting and swivelling the engine as well as for handling heavy loads ensure optimum working conditions and constitute the basis for supreme product quality.

As part of quality control, both the water chamber and the depressurised oil chamber of every single engine are checked for leakages, followed by hot run testing on the engine test bed.

Quality assurance via data transfer.

The engines are mounted to special devices and to driverless system carriers that house a data unit which stores the most important production data. During the course of the assembly process, the data unit records crucial, quality-related data, such as the tightening torques or valve play and stores this data in a database. The data carriers also ensure that the right program, intended for the engine under construction, is activated at the automated assembly stations. At the assembly stations fitted with integrated tools, data communication ensures that the personnel use the right tools with the correct tightening torques.

Core components such as cylinder heads or connecting rods are provided with a code, which enables the staff to keep track of each component from the very moment it reaches the factory to mechanical processing through to its installation in the engine.

At work stations where complexity is particularly high, the monitors display which of the colour-coded crankshaft bearing shells has to be inserted.

Skilful craftsmanship: an absolute must.

Particularly when it comes to the pre-assembly of the valve train and the crankshaft drive, experience, meticulousness and skilful craftsmanship are a must. The work on the kinematics of the VANOS variable camshaft control and the synchronisation of the ten individual throttle butterflies is also very demanding and requires considerable dexterity by the assembly staff.

The two-piece crankcase renders it necessary to use a special sealing technique. A sealant is injected fully automatically into the sealing surface via a circumferential groove. As soon as the sealant comes out at the other end, it is hardened at that particular point by means of UV light. The sealant in the interior hardens as the assembly process continues.

Sophisticated logistics.

The supply of parts and components demands the highest of logistics standards as each of the four engine types with its numerous variants is made of about 400 different parts and components. The associates are an integral part of this complex process as they must use different parts and tools, depending on the type of engine manufactured.

The specialist engines are made to order, meaning that the customer-specific assembly does not start before the receipt of an order from one of the vehicle plants. Depending on the specifications, it takes up to 24 hours for an engine to pass through all stages of the assembly process.