M127

Developed in the mid-1950s from the M180 carburetor six, the M127 kept its 2.2 liters and added mechanical Bosch manifold injection, metered by a copy-milled three-dimensional cam the engineers called the Kartoffel — the potato — governing mixture on two parameters at once. Under Rudolf Uhlenhaut five specially modified 190 SLs were built to test it, and a production 220 SL was seriously on the cards before being abandoned. The engine went instead into the Ponton 220 SE and then the W111 fintail saloons, coupés and cabriolets: 115 PS at first, 120 PS from August 1959.

Its second act is the one that lasted. For the W113 of 1963 the bore went out 2 mm to 82 mm for 2,306 cc, the two-plunger pump gave way to a six-plunger unit, and compression rose to 9.3:1 — 150 PS, and the character of the 230 SL. Underneath it remained an old design, with a crankshaft on four main bearings, one chain-driven camshaft and two valves per cylinder. The 2.5-liter M129 displaced it in the saloons in 1965, and the Pagoda moved on to the 250 SL in 1966.