Panhard et Levassor X46 1924 with 'Sans Soupapes' Landaulette. The 'Sans Soupapes' name is a reference to the valveless technology licensed from American Charles Yale Knight. Panhard used the Knight system until 1924 when it came up with its own version and from thereon fitted this to its entire model range until 1940.

Panhard Levassor X45 40/50 1924. Powered by 6,335cc Sleeve-Valve ('sans soupapes') 35 CV 8-cylinder engine. Panhard produced its own version of the Knight patent sleevle valve engine, which had the advantage of being very quiet in operation, but al;so very smoky as it burned the oil that lubricated the sleeves.

Panhard et Levassor X46 1924 with 'Sans Soupapes' (Sleeve Valves). Powered by a 3,180cc four-cylinder Knight double sleeve-valve engine. Panhard had licensed the Sleeve Valve technology from Knight.

Panhard et Levassor X46 1924. Coachwork is by Salmons & Son of Newport Pagnell (Tickford) and is an open drive Landaulet

Panhard Levassor X45 40/50 1924. Powered by 6,335cc Sleeve-Valve ('sans soupapes') 35 CV 8-cylinder engine.

Panhard Levassor X45 40/50 1924 - Interior. The coachwork is a replacement dual cowl skiff made by a British craftsman. The car had previously carried a number of different coachworks.

Panhard Levassor X45 40/50 1924. The coachwork is a replacement dual cowl skiff made by a British craftsman. The car had previously carried a number of different coachworks.