Beginning in the middle of the 2010s, there has been a growing trend towards the utilisation of steel pistons in passenger car engines. Many leading car manufacturers now use the innovation. Ultimately, increasing pressures and high temperatures mean that modern engines have to meet tougher requirements than ever before. These requirements can be met more reliably by a smaller and lighter steel piston. In response to this development, Motorservice now offers aftermarket steel pistons for the Mercedes-Benz OM 642.855, OM 642.873, OM 654.920 and OM 656.929 engines - spare parts in OEM quality.
Advantages of steel pistons
The constantly increasing use of steel pistons can be attributed to a number of advantages over aluminium pistons: With steel pistons, combustion pressures of well over 200 bar and peak temperatures of over 400 °C are possible. This enables a greater power density to be achieved, allowing further downsizing of the engines. In addition, the thermal expansion of steel is significantly less than that of aluminium: A steel piston is closer to the optimum shape even when cold. This means that the necessary clearance for movement can be made significantly smaller and the interacting sliding parts can be coordinated better with one another to reduce friction. The surface coatings developed by Kolbenschmidt especially for steel pistons amplify this effect, bringing further improvements in even running and cold running properties of the steel pistons.
Smaller, lighter, more efficient
The smaller clearance and the narrower gap dimensions also reduce oil consumption and blow-by gases. Operational safety is also increased, both in the cold start phase and at maximum load in the higher temperature range. The higher strength and temperature resistance of steel allow very thin-walled designs. This enables steel pistons that are lighter than aluminium pistons to be constructed. The compression height of the piston and its total length can be reduced. The new designs can bring savings of around 30 percent compared to aluminium. The larger piston pin diameter than with aluminium enables higher force transmission to be achieved. Ultimately, the use of steel pistons allows a smaller, lighter and more efficient design of the entire engine.
As a sales organisation for Rheinmetall Automotive's aftermarket activities, Motorservice acquires a large proportion of its range internally from within the group, including the subsidiaries Kolbenschmidt and Pierburg. The internationally active spare parts specialist also has the know-how of a large international automotive supplier. Customers therefore benefit from products in OE quality.