Mercedes also unveiled at the 1951 Frankfurt Motor show a larger 3.0-litre M186 ‘big six’ inline-6 to power its new flagship 300 (W186) Adenauer four-door saloon.

The W180 Ponton 220S Sedan, Coupe and Cabriolet of 1956-1959 benefited from the up-rated M180.924 which delivered 124 hp (92 kW; 126 PS).

In 1958 Bosch multi-point injection was added to the 2.2-litre six and the engine, now giving 113–134 bhp (84–100 kW; 115–136 PS), was redesignated M127.

The engine is rated, according to DIN 70020, 120 PS (88 kW) at 4800/min, and produces a maximum torque of 19.3 kp⋅m (189 N⋅m) at 3900/min, equivalent to a BMEP of 11.1 kp/cm2 (1.09 MPa).

Daimler-Benz achieved this BMEP by using, in addition to the manifold injection, resonance effect induction, giving the engine a volumetric efficiency greater than 100 per cent.

Connecting rods were slightly shortened, reflecting the 6 mm (0.24 in) longer stroke in a block of unchanged overall height.

The redesigned cylinder heads incorporated larger ports, and the valve diameters were increased by 2 mm (0.079 in).

The final incarnation of the M180 line of engines was the 2.5L M123, fitted with the notorious Solex four-barrel carburetor in the W123 chassis 250 produced between 1975 and 1985.