OM 665 SS MM Castagna

Vehicle Overview

The OM 665 SS MM Castagna is a striking example of early 20th-century Italian automotive excellence. The OM 665 Superba was introduced in 1923, quickly gaining a reputation for its racing pedigree, which culminated in dominating victories, including the first three positions at the inaugural Mille Miglia in 1927. This model was a symbol of OM’s engineering prowess, blending performance with luxury, and its success on the racetrack established it as one of the brand’s most celebrated cars. In 1929, OM sought to further enhance its sports car offerings by introducing a supercharged version of the 665 model, powered by a Roots supercharger. This addition significantly improved performance, allowing the vehicle to compete against the best in the world. It wasn’t just about power—OM’s focus on precision engineering ensured that these supercharged models could deliver exceptional reliability as well. This specific car, is on display in the museum Nicolis, is a 665 SSMM model, an important variant of the 665 series. Notably, this version was modified by the English OM importer, who replaced the original side-valve cylinder heads with overhead-valve versions. These modifications were part of an effort to enhance the car’s performance, increasing its racing potential and making it more competitive on the international stage. The new heads were crafted from cast iron, and the design was optimized for performance with a flat combustion chamber and domed pistons to accommodate the low-positioned spark plugs. This change significantly improved the combustion process and increased the engine’s efficiency. The OM 665 SSMM’s unique cast-iron cylinder block included twelve 18mm spark plugs—six on each side—further enhancing its performance. The ignition system was carefully crafted to ensure optimal power output, with a magneto and coil ignition system for the road version. Racing versions of the car may have used a dual magneto system for added reliability and performance under the extreme conditions of racing. The light, well-shaped bodywork by Carrozzeria Castagna was one of the key factors in the car’s remarkable performance. Castagna’s expert craftsmanship ensured that the car was not only aerodynamic but also visually stunning. The result was a car capable of reaching speeds of 150 km/h, making it a formidable competitor both on the track and on the road. The OM 665 SS MM Castagna stands as a testament to the artistry and innovation of its time, blending advanced engineering with aesthetic beauty. The car represents a pivotal moment in OM’s history, embodying the brand’s commitment to performance and luxury, and solidifying its place in the annals of automotive history.