Mercedes-Benz M188 engine

The Mercedes-Benz M188 is a 3.0 litre single overhead camshaft inline-six, the 1952 variant of the M186 big six that was fitted only to the W188 300 S coupe, cabriolet and roadster. It added a third downdraft Solex carburettor to the M186 and raised compression to 7.8:1, which lifted output to 150 hp at 5,000 rpm, up substantially from the 110 hp of the M186. It stayed in the 300 S through 1955, when the M199 was introduced for the successor 300 Sc. The M186 family shares many design features with the smaller M180 shown at the same Frankfurt Motor Show in April 1951, including a staggered valve arrangement and rockers run from a single overhead camshaft on a duplex chain, but the two are of completely different design with little interchangeability of parts.