in a side-valve cylinder head. The camshaft was driven by bevel gears on a vertical shaft at the front of the engine, as on the 3 Litre engine. The Bentley's tanks - radiator, oil and petrol - had quick release filler caps that opened with one stroke of a lever. This saved time during pit stops. This 4½ was equipped with a canvas top stretched over a lightweight Weymann body. The hood structure was very light but with high wind resistance (24 Hours Le Mans rules between 1924 and 1928 dictated a certain number of laps for which the hood had to be closed). The steering wheel measured about in diameter and was wrapped with solid braided rope for improved grip. Brakes were conventional, consisting of drum brakes finned for improved cooling and operated by rod. Semi-elliptic leaf springs were used at front and rear. Blower Bentley The essential difference between the Bentley 4½ Litre and the Blower was the addition of a Roots-type supercharger to the Blower engine by engineer Amherst Villiers, who had also produced the supercharger. W. O. Bentley, as chief engineer of the company he had founded, refused to allow the engine to be modified to incorporate the supercharger. As a result, the supercharger was placed at the end of the crankshaft, in front of the radiator. This gave the Blower Bentley an easily recognisable appearance and also increased the car's understeer due to the additional weight at the front. A guard protected the two carburetters located at the compressor intake. Similar protection was used, both in the 4½ Litre and the Blower, for the fuel tank at the rear, because a flying stone punctured the 3 Litre of Frank Clement and John Duff during the first 24 Hours of Le Mans, which contributed to their defeat. The crankshaft, pistons and lubrication system were special to the Blower engine. It produced at 3,500 rpm for the touring model and at 4,200 rpm for the racing version, which was more power than the Bentley 6½ Litre developed. In 2019–2020, Bentley scanned all 630 components that made up the Blower so that they could digitally re-create it and create 12 new models. In December 2020, Bentley Blower Car Zero, the first example of the Blower Continuation Series was presented. The car was built in Crewe according to the historic specifications and based on the production processes of that