It was also a very big seller and was easy to maintain. In 1934 BMW took to work on their new 845cc four-cylinder engine. It had a 80mm stroke and a 58mm bore. This gave it 22BHP and a 50mile per gallon (MPG) fuel usage. BMW abandoned the four cylinder concept till the early 1960's when if made a 1.8 litre four cylinder that was capable of 130BHP. In the late 1970's BMW produced a record amount of this engine. In the early 1980's BMW Produced a new 1.8 Litre Four cylinder with 24 valves and a dual overhead camshaft. They were capable of 140BHP. In the early 1990's BMW resized the valves in this model engine and it gained a few BHP.
The BMW six cylinder engines are the most widely produced and famous BMW motors. All BMW six cylinder engines are inline. The first BMW six cylinder was made in the early 1930's. It was 1173cc and had the same valve layout as the previous four cylinder engines. It had a thicker block to put more metal between cylinders and had wider main bearings than the early four cylinders. In April 1934 BMW announced the creation of a long stroke six cylinder. They had a power output of 34BHP. This same motor was made into a triple carbureted version that gave it 40BHP. In 1935 Germany removed the tax on large engines and the power in this early six cylinder was upped to 55BHP. The engine was again redesigned in 1940 with hemispherical combustion chambers and relocated valves. It had a max power of 80BHP. A new 3485cc six cylinder was developed in 1941 as a replacement for the older long stroke six. It shared several of the same design features but was not nearly the same motor. In the mid sixties BMW designed a new set of 6 cylinder engines. They were called the Junior sixes and the Senior sixes. The Junior sixes had a smaller block and a smaller stroke than the Senior sixes. One of the most famous of the Junior sixes was the 2.3 Litre which had an electronic fuel injection and 120BHP.