The 'rocker shaft support bolt' for the Citroen 11CV is a critical engine component that securely fastens the rocker shaft to the cylinder head. This bolt provides the necessary stability and prevents loose connections that might cause engine issues during operation. It is essential for the smooth functioning of the engine valves and contributes to the overall performance and longevity of the car. These parts are specifically designed to fit the classic Citroën 11CV, a vehicle renowned for its style and elegance in the early 20th century.