The B series

 The B series engine as fitted to most MGBs is a utilitarian workhorse of an engine. Archaic in design, inefficient in execution and a heavy lump of iron. It is also a wonderfully designed and manufactured piece of automotive brilliance. As John Thornley once said, "Austin never made a good car and never made a bad motor". MG had used a long succession of engines from Morris, Wolseley and Hotchkiss before the BMC merger when they were forced to start using Austin engines due to a consolidation of parts across the entire range. Austin engines were chosen not only because they were good engines, but because BMC was ruled by Austin people with very little love for anything Morris and especially MG.

The B series engine can be traced back to the 1930's when Austin released their Austin 10. The basis of their new engine would foreshadow Austin engine designs for many years to come but it was the need for a new 6-cylinder overhead valve truck engine in 1939 that influenced the A and B series 4-cylinder engines immediately post war. Austin had always designed engines based more on reliability than performance and this conservative attitude would dictate Austin engines well into the future. The basic design features like a strong heavy crank and crankcase, pressed steel sump, internal oil galleries and long stroke with cam buried deep in the block would carry over to the post war series A and B engines. Luckily for us the very talented Harry Weslake had started consulting for Austin back in the early 30's and had worked out a very decent head design considering the immense limitations put on him for the B series by the time it arrived.

With the formation of BMC (British Motor Corporation) in late 1951 came with it the need to integrate and design cheap, reliable and mass producible products, and engines were lightly considered from all the divisions of the BMC stable. The idea of the A, B and C series engines was initiated in Dec 1951 and much of the design credit must go to a brilliant man named Eric Bareham. By 1954 when the B series was introduced it was quickly powering most of the mid-sized saloons in the BMC range with the very similar but smaller A series powering nearly everything under it. I won't go into possibly boring and tedious details about design, engineering and manufacturing but suffice to say that even though Austin designed great, if not very conservative engines for the day, their foundry and machining processes were second to none in the entire world. British foundries led the world in metallurgy and practice until the 1970's and Austin/BMC engines are very, very well-made items indeed.

The B series is not a high-performance engine. It's not as beautiful as a Jaguar XK engine or as fascinating as a Coventry Climax but it is an honest, hardworking collection of mechanical prowess. It is a long stroke, slow revving, heavy block of cast iron but it is also simple, robust, reliable, easy to work on and will take an absolute hammering far beyond its original design criteria. Its cons are also its pros. Knowing and understanding this should instill much confidence in the average MGB owner because, you don't really have to worry about these engines. Even 60 years later they will just keep going with the minimum maintenance and a little bit of love. There are B series engines out there that have covered well over half a million miles and still give very little complaint. This is all very comforting news to an MGB owner because, well, it means you can jump in an MGB any time and just go.