Construction The engine was of conventional construction with a one-piece crankcase and cylinder block in cast iron with the crankcase extending down to the lowest level of the main bearing caps; with a cylinder head, also usually in cast iron, and a sump made from pressed steel for rear-wheel drive vehicles. Early engines used a three-bearing crankshaft, but later engines used five bearings. On all except the rare twin overhead camshaft variant, the camshaft — which was chain driven and mounted low in the block — operated the overhead valves via pushrods and rocker arms. The two inlet ports in the non-crossflow cylinder head were shared between cylinders 1 + 2 and 3 + 4 and the three exhaust ports between cylinder 1, 2 + 3 and 4. Valve clearance was adjustable by screws and locknuts on the rocker arms. Another unconventional characteristic of the engine is that the bore spacing is not constant between all four bores. The distance from cylinder 1 to 2 is 3.4375"; 2 to 3 =3.875" ;and 3 to 4 =3.4375". The B series shares many design features (such as the heart-shaped combustion chambers and siamese inlet ports designed by Harry Weslake), as well as its basic layout and general appearance, with the smaller BMC A-series engine. However another difference was its block's full-depth skirt which provided excellent bottom-end strength. This made the engine highly durable and suitable for developing into diesel versions in later years. Engine types litre engines The version was the first version of the engine. The bore and the stroke was . The maximum power output was at 4300 rpm. After the formation of British Motor Corporation (BMC) the new B Series engine was used in the following vehicles: 1954–56 Morris Cowley 1954–56 Austin A40 Cambridge 1954–55 Nash Metropolitan 1200 (used unique "2G" engine prefix) Massey-Harris Combine Harvester litre engines The version was first used in 1953 in the MG Magnette ZA in twin carburettor version and in 1954 in the Morris Oxford series II and Austin Cambridge. In 1957, it was used in the original MGA. Output in twin carburettor form was and with a single carburettor. Bore and stroke was . There was also a diesel version of this engine size. Power output was at 4,000 rpm and torque at 1,900 rpm. The 1.5–litre diesel engines were made in India by Hindustan Motors for many decades until the production