Although the forged-steel connecting rods are similar to those used in the spark-ignition engines, the pistons are of far more robust dimensions and are totally different in design, since they must be capable of attaining very high compression pressures and withstanding the loads of compression ignition. As on other Volkswagen engines, full-floating piston pins are secured by circlips. The connecting rods for the turbo diesel engine have greater piston pin clearances, however, and the piston skirts are notched for clearance with the piston-cooling oil jets.