Lorraine-Dietrich B3-6 (15 CV) History

Introduced in 1922 as the third variant in Marius Barbarou's post-war six-cylinder range (following the 1919 A1-6 and B2-6), the B3-6 shared its 3,445 cc six-cylinder engine — overhead valves, hemispherical combustion chambers, aluminium pistons, four-bearing crankshaft — with its siblings but could be specified on either a short or long wheelbase. All variants fell within the 15 CV fiscal horsepower bracket.

Racing versions of the B3-6 dominated Le Mans in consecutive years. In 1925 the Lorraine-Dietrichs ended Bentley's early dominance, winning outright with a sister car finishing third. In 1926 Bloch and Rossignol led a historic 1-2-3 sweep at an average of 106 km/h — the first time any marque had won Le Mans twice and the first clean podium sweep in the race's history. The factory promptly listed a short-wheelbase Sport variant in its catalogue under the name 'Le Mans', featuring dual ignition, twin Zenith carburettors, an oil cooler, servo-assisted brakes, and a stone guard.

Road-going B3-6 tourers and cabriolets continued in production until 1932. A surviving 1933-dated Bonhams auction example (chassis 125674) demonstrates that the engine designation remained in use on bespoke coachbuilt bodies into the early 1930s, though factory volume had wound down significantly after the 15 CV's commercial peak in the mid-1920s.