The main change was an upgrade to the M130 engine with maximum power and maximum torque, which finally gave the W 113 adequate power. The performance improvement was achieved by increasing bore by , which stretched the limits of the M180 block, and required pairwise cylinder casts without cooling water passages. This mandated an oil-cooler, which was fitted vertically next to the radiator. Each engine was now bench-tested for two hours prior to being fitted, so their power specification was guaranteed at last.