With such excellent books on M.G. history about, it would be utterly pointless trying to retell it all. If that is what you are after, then obtain 'M.G. by McComb', 'Magic of the Marque', 'McComb, Maintaining the Breed', all by F. Wilson McComb; 'Tuning and Maintenance of MG's' by Phillip H. Smith; 'The Magic of MG' , 'MG, Magic of the Marque' by Mike Allison; and 'MG The Untold Story' by David Knowles. Once you have absorbed these, you are an 'expert'. This book is a collection of information and stories I have collected over about 30 years, with obvious reference to MG history books. It is not a workshop manual, even though there are hints and tips from experience of working on them, on the XPAG, 'A', 'B' and 'C' series, and the V8, all of which I have owned and run for a number of years, (especially the XPAG and 'B'.) It is not a history book, even though the chapters and models are in order. It is an information book for an enthusiast by an enthusiast, who saw something somewhere about M.G. engines, and needs it all in one book. The political infighting and hard commercialism of production and profits does not interest me, so I have deliberately avoided it. Contained within these pages are information and my views, about the engines that M.G. used after the company had come under firm control of Morris Motors Ltd.
Other reference matter, some read a long time ago I might add, was 'M.G. Cars', by C.P. Davidson; ‘The Book of the Austin A40', by Ellison Hawks; 'Wolseley Cars' and 'Morris Engines', by D.V.W. Francis; 'BMC 'B' Series' by Lindsay Porter; 'Tuning the 'A' Series', by David Vizard; 'Post War Baby Austins, by Barry Sharratt; 'Morris Bullnose and Flatnose', by Peter J. Seymour; 'Y type Saloons and Tourers' by John Lawson; 'The Morris Story', by Brian Whittle, 'The Rover Story' and 'Triumph Spitfire' by Graham Robson; 'British Leyland', by Jeff Daniels; 'The Breakdown of Austin Rover', by Williams, Williams and Haslam; ''Metro', by Mark Steward; 'Lord Nuffield', by Peter Hull; 'The Private Motor Car', a collection of the Crompton–Lanchester Lectures to the IME in 1960; and many, many road tests found in the 'Brooklands Books' collection, from 'Autocar', 'Motor', 'the Light Car'; articles in the MGCC magazine 'Safety Fast'; articles in the MGOC magazine ' Enjoying MG'; articles in the MG Octagon CC magazine, 'Bulletin'; my own experiences since 1960, and items that I have forgotten from whence they came.
MG Cars Manuals PDF
There are lots of pretty M.G. books about, full of excellent photographs and text that gloss over important technical parts, or simply do not mention them. Others go too deep and lose the reader in a morass of figures and graphs. The simple aim of this book is to get round the difficulty of finding out that odd bit of information you know you saw somewhere. The mechanical components of an M.G. such as its engine, has to be looked at with the view that after 1935 M.G. used and developed Morris, and later, BMC/BL, then Rover, parts for their own use. Some enthusiasts either forget, or choose to ignore this.
The excellent engine drawings included are those of Motor, Autocar, Sphere, and Light Car magazine technical artists, and are shown as an 'art' of their times. This is not a historical epistle, nor is it a story of M.G., but if you like engines, and those of M.G. cars in particular, and their roots, read on.
M.G. Engines, Care of Morris. (1935 to 1955)
The internal combustion engine (ICE) has now been with us for some considerable time, and it must now be under the bonnets of millions upon millions of vehicles worldwide. The M.G. motor car comes into the picture in approximately 1923/24, evolved by Cecil Kimber, in the early days of the Automobile. The engines used before then were purchased from outside the main Morris Company, but as the Morris Empire grew and grew, so he began to buy up his suppliers. The company of Hotchkiss in Gosford Street, Coventry were purchased in 1923 to be renamed Morris Engines Branch. They supplied Morris with the engines for the later model of the Bull Nose (and M.G.) saloon cars. Hotchkiss et Cie had moved to the United Kingdom from France in WW1 to escape the Germans, to continue making armaments, and carried on using their original machine tools and equipment.
The machinery and tools had come over from France, and this included the thread cutting dies and taps used on their guns. These threads of an unusual French Metric size were used up until 1956 in the last 'X' series engine in the Wolseley 4/44, having been used in virtually all Morris and M.G. engines till then. These metric threads are not quite the same as those used today. The last M.G. to use such threads was the TF1500 in 1955. Such nuts and bolts have British BSW/BSF head sizes, so that the average British DIY owner or motor mechanics tool kit could still be used, but with these odd metric threads. From then on, starting with the M.G. 'Z' Magnette in 1953, Austin engines were used under the umbrella of the British Motor Corporation, or BMC for short. These BMC engines used American based Unified Fine (UNF) and course (UNC) threads, (ANF and ANC in the USA) in the 'A','B' and 'C' series M.G. used. Such nuts and bolt heads had to be used with spanners that are termed "A/F", indicating the distance Across the Flats, a common size for instance, being 1/2" AF. Later still, standardised ISO metric sizes took over with the 'A' Plus, 'O','R','S', and 'K' series engines of Austin/Rover.
Other items used with the Morris engine were made by outside contractors, and they too were taken over one by one, so that Osberton Radiators became Morris Radiators in 1922 as Morris was their only customer. Skinners Union who made SU carburettors for Morris were purchased in 1926. The next year the first M.G. factory was built at Cowley, and then M.G. moved to Abingdon in 1929.
The Hotchkiss 'side valve' (sv) and Morris/Wolseley 'overhead camshaft' (ohc) engines used by M.G. before WW2 are well documented. This book is about those used by M.G. from 1935/36 when M.G. became part of The Nuffield Organisation, from the little TA Midget right up to the latest Rover/M.G. MGF sports car.
Like all things, a car engine is a compromise. It would be nice to be able to use the best materials, and hand assembles the accurately machined components to the 'Blue Print'. A blue print is a 'working copy' of the drawing of the engine from the design office. They were blue because of the method of copying such large drawings in those days. In reality the manufacturer has to use metals that are cheap, hard wearing, will machine easily, and take up complicated cast shapes. The engine must be designed for an assembly line as well as a long life. As M.G. was originally a small part of a huge motor manufacturer, Morris, they were limited to using parts that were available from the huge corporate parts bin. As a mass produced component for millions of cars, an engine has to have tolerances, meaning that a cylinder bore will be between two sizes, the variation often between two–thousandths of an inch, (0.002"), and the piston being made to similar limitations. So a new engine piston could have up to 4 thou' "play" if assembly was not checked for quality. To limit this, pistons would be graded so the assembler could select a set that would not be so slack. Camshafts and crankshafts would be under similar tolerances, (i.e. a half to one thou' plus or minus) simply because machines did not exist that could turn out thousands of parts without tiny differences. Experienced assembly line workers, worth their weight in gold, at Morris Engines, could select the correct parts to fit together within the tolerances. Morris paid good wages and had a large staff of Quality Inspectors, and used the best materials. So unlike Rolls Royce, cars for the masses like Morris and M.G. are not perfect, but as close as possible within a price.
Company Policy.
Motor manufacturers are companies, and companies exist to make money, not cars. Often the management are not all enthusiasts, but businessmen and women, and a good idea in business is to use common base components. This keeps prices down, allows more choice within a range, and can keep quality up, because of mass–production. In M.G's case it meant they had access to massive investment that was not for only them, but all the other marques as well. Under BMC this meant they could use new engines first that on their own they could never have afforded to develop and produce. Under Nuffield it was a similar case. It is no good being a self–contained unit in a company if you cannot call on its larger resources or help. If the bits you use, like engines and other mechanics, are suitably modified to suit your needs, i.e. engines tuned for sports cars, but backed by long reliable service in more mundane cars, a car can still have dignity and quality. For instance
M.G. produced 524,862 MGB's, but no one noticed that BMC produced 900,000 Farina saloons; both have the 'B' series. Or that between 1953 and 1955 M.G. made 9,600 TF Midgets, but Wolseley made 30,000 4/44 saloons, both have late versions of the Morris 'XP' series engine. Or that M.G. made 150,496 'A' series engined Midgets, but in the Morris Minor there were 1,293,331 alone.
PRODUCTION.
The Beginnings of an Engine.
Any engine begins life as an idea, (often tempered by the need to re–use parts of the old one due to costs) then a drawing, then this is transferred into the three dimensional wooden 'pattern' that will be used to make the moulds it will be cast in. The Morris engine design office and pattern makers shop was at Coventry, as was the iron foundry. Later the Ward End premises of Wolseley would be involved in engines as well. The wooden mould will be given a number, often the items part number, taken from the design offices drawing number. This number will follow the item through to the spares book sometimes. For instance the XPAG TC/YA cylinder block is pattern number 24146, the MGB 1798cc five main bearing cylinder block is 12H3503, the same as the Marina 1800 and the Sherpa 1800 diesel. The 1800 Marina cylinder head is 12H2709, and the Midget 1098cc cylinder head 12G206. These numbers are cast onto the metal and easily seen and rough looking; do not mistake them for serial numbers, (the engines individual identity number) that are stamped in much later during production. The medium used for the engine block and cylinder head, is often grey cast iron, as this flows very easily and will make intricate castings, and if cooled slowly will form graphite flakes in the metal. Graphite assists easy machining and makes the casting hard wearing, and partially self–lubricating. Grey cast iron also has a very small shrinkage rate after casting, unlike aluminium. Cast iron cylinder heads cannot withstand lead–free petrol on the exhaust valve seats, unless they are modified by fitting hardened steel inserts. The Pattern Maker who cut and carved the wooden pattern, will have had to make an outer pattern, and one that is in fact the hollow innards of the engine, such as the water spaces, called a 'core'. These are in the 'negative' so to speak, as the casting is done in special sticky sand, hence the term 'sand–casting'. A negative sand mould is made of the engine block, or head, then a 'core' mould is made in sand and baked, then suspended inside the first, via 'core holes'. Once the iron is poured in under gravity, it solidifies around the sand shapes. It is then broken open and the cooled casting carefully cleaned of all sand, both externally and from the 'core', the waterways and ports, etc. The holes that once supported the core are then machined, and core–plugs fitted, thin discs of concaved steel sprung into place, in the machine shop after. Grey cast iron was used almost universally for car engines, until aluminium supplanted it in modern cars once costs dropped. A sand casting has a natural 'sandy' finish; you can almost make out the grains.
M.G. Engines from the TA Midget onwards
The pedigree of the Morris Engines Division included not only the background of Hotchkiss, but that of Wolseley, of Ward End, Coventry, whom Morris had purchased in 1927. He was after the Wolseley engines of advanced design, as well as wanting to outbid his competitor Herbert Austin. The overhead camshaft engines (ohc) of Wolseley had found their way into many M.G. cars including the tiny M–type Midget. However, these ohc engines based on Wolseley’s WW1 experience of building Hispano–Suiza aircraft engines under licence, had proved to be expensive to produce and complex to keep running. So most Morris cars were fitted with humble side valve (sv) engines, and the Wolseley using a cheap overhead valve (ohv) conversion of the same engines. For by 1935 Wolseley’s had become an up–market Morris, though after WW2 there was a short return to the ohc six cylinders for a while for big Wolseley cars. In 1938 Nuffield purchased Riley Motors, who had their own well designed four cylinder high–camshaft engine, but this engine never affected M.G. as Riley were left to run themselves for some time.
The PA/PB ohc Midgets were the last model to use that engine, the ohc Morris Minor reverting to a side valve back in 1932, and had been the source of many of the Midgets components. When the tiny ohc 'M'–based Midgets engine stopped production, in the upheaval of Leonard Lords thinning out of the numerous models M.G. and Morris/Wolseley were building in 1935, M.G. had to look into the Morris cupboard of engines for a successor to the nice ex–Wolseley units.. From the rather empty shelves they found the ohv conversion of the pedestrian Morris 10/4 Series 2 sv unit, (10hp four cylinder.) This was fitted to the Series 3 Morris 10/4 and Series 2 Wolseley Ten/40, (10hp rating with 40 brake–horse power, or bhp) in 1935, being termed a 'MPJW' in the Wolseley and a 'MPJM' in the Morris, and was of 1292cc, with a bore of 63.5mm and a 102mm stroke. This 102mm stroke can be traced back to the early Bull Nose Morris engines as well. The rather out of date 1910 RAC rules on Horse Power (hp) still had effect, and were used by the government for levying road tax tolls. This rule relied on only the bore of the engine for its formula, in this case giving these Nuffield four cylinder cars a rating of 10hp. After 1936 all the Morris firms were combined into The Nuffield Organisation, (Morris becoming Lord Nuffield in 1935) to get around super–tax problems, as one or two were the personal and private property of William Morris. There were other parts from the Morris Ten/Four series 3 that were to be used on the 'M'–type Midgets replacement, the 'TA', such as hydraulic brakes, gearbox, axles, etc.