Brief History and Development Of Mirrlees Blackstone

Research & Development

Curent Range


In 1840 an engineering partnership was founded in Glasgow to manufacture cane sugar machinery. This business was founded by three brothers, Peter, William and Andrew McOnie and the original title of the firm was P & W McOnie. Mr William, later Sir William McOnie, at one time Lord Provost of Glasgow, retired from the firm in 1848 and Mr J.B. Mirrlees became a partner. the new title of the firm then became McOnie and Mirrlees.

When Peter McOnie died in 1851, Mr Mirrlees appointed William Tait as manager and the firm continued as McOnie and Mirrlees until 1858 when Mr Tait became a partner. The name of the firm then changed to Mirrlees and Tait. Under this title and direction the house remained for ten years, when, on the failing health of Mr Tait, Mr Watson, later Sir W Renny Watson, was taken into partnership and the title of the firm became, in 1868, Tait and Watson. Mr Tait died in 1870 but the title of the firm remained unchanged until 1882.

During this period the firm acquired from David McColley Weston of Boston, USA, sole rights for his inventions in the United Kingdom and the principal cane sugar countries of the world. these inventions increased development in the firm to such an extent that in 1883 the partners, with Mr John Laidlaw as Managing Director, built a new works and formed a new company Watson, Laidlaw & Company.

In 1885 Mr R. A. Robertson and Mr J.C. Hudson, who had been for some time in the management of the business, were admitted as partners and the title of the firm changed to Mirrlees, Watson & Company. Mr Hudson retired in 1888 and Mr W. J. Mirrlees, eldest son of Mr J.B. Mirrlees, became a member of the firm.

The patent rights of Mr Home T. Yaryan in the evaporating apparatus which bears his name, were acquired in 1887, and the intimate association of the firm with the Yaryan Company resulted in the reconstruction of the company as Mirrlees, Watson, Yaryan & Company Limited in 1889.
Picture of 1897 Air Blast Single
Seven years later, on the motion of Mr R.A. Robertson, three members of the Board of the Mirrlees, Watson & Yaryan Company Limited, formed a committee to make investigations into the practical possibilities of a new internal combustion engine patented by Dr Rudolf Diesel. During March 1897 the committee visited Germany and, after studying Dr Diesel's 20 BHP engine, an agreement was signed whereby the patentee granted an exclusive licence for the manufacture and sale of the diesel engine in Great Britain. Following this agreement, the first engine was completed in November 1897. This was the third diesel engine in the world and after exhaustive tests by Professor Watkinson of the Royal Technical College, Glasgow, was later put into regular service on the company's premises. It is now to be seen in The Science Museum at South Kensington, London. This engine is a single cylinder, four cycle, air injection unit, 300 mm bore by 460 mm stroke, developing 20 BHP at 200 r.p.m., the engines being built up to six cylinders in size and many hundreds of this type were supplied as the range extended. Before this type of engine was superseded, it was sold in a modified form as an airless injection engine.

Various difficulties arose following the commencement of building diesel engines and these proved a heavier demand on the financial resources of the company than the directors were prepared to maintain. So it was that in 1899 the Dieselmotoren Company of Augsburg bought back the exclusive licence in exchange for a non-exclusive licence and a considerable sum of money. Also in that year the Company was again reconstructed and became the Mirrlees Watson Compnay Limited. In 1900 mr Charles Day became manager and under his direction rapid progress was made with diesel engine manufacture.

160HP Marine Around the year 1903, the success of the 50 BHP per cylinder type engine led to a demand for a lighter engine with higher speeds and the Admiralty ordered two engines, each of 160 BHP at 400 r.p.m. for installation in the battleship HMS Dreadnought. this battleship was the first British vessel to have diesel engines installed on board. The type fitted developed 40 BHP per cylinder and were of the enclosed type with forced lubrication, with a bore of 11.5 inches and a stroke of 12 inches. this diesel installation was the forerunner of many more units installed on His Majesty's Ships for auxiliary purposes.

120 HP Marine Engine
During 1906, the Admiralty specification required lightweight diesel engines for the propulsion of pinnaces and Mirrlees designed a four cylinder unit of 120 BHP at 400 r.p.m. These engines had bed plates of aluminium and columns of manganese bronze. The piston diameter was 9 and three quarter inches with a stroke of 12 inches.

It was shortly after this that the diesel engine business of the Company at Glasgow increased so rapidly that a decision was reached to manufacture diesel engines at Hazel Grove, near Stockport in Cheshire, and to this end Mr. Charles Day, then Chairman of the Company, came to Cheshire and with the financial assistance of Mr H.N. Bickerton of the National Gas & Oil Engine Company Limited formed Mirrlees, Bickerton & Day Limited and the construction work work culminated in the factory being opened during October, 1908, for the manufacture of diesel engines ranging in power from 50 BHP to 750 BHP. 1912 also saw the first installation of electric propulsion for marine purposes. This consisted of two 300 BHP Mirrlees engines driving DC generators, in turn coupled to propulsion motors driving through a shaft to the propeller. During 1912 also, Mirrlees designed a 16 inch by 19 inch enclosed type engine developing 80 BHP per cylinder at 250 r.p.m. many engines of this type were sold during the years 1912 - 1927 and the design was modified to provide a unit having a bore of 17 and a quarter and a stroke of 24 inches, giving 120 BHP per cylinder at 250 r.p.m.

Broken Hill Australia With the increased load demand at Power Stations, Mirrlees next designed a larger engine during the latter part of 1912, which in it's production form was a cross head type unit having a bore of 21.5 inches and a stroke of 24 inches giving 166 BHP per cylinder at 215 r.p.m. This engine was fitted with water cooled pistons and the engines were installed in many large diesel generating stations. many multi-engine contracts were obtained for this engine, both at home and abroad.

During the war years, 1914- 1918, the factory at Hazel grove, in addition to producing their standard range of diesel engines, also developed a special type of oil engine for installation in the 'tank' which was first used in 1916 and revolutionised ideas in warfare. the blockade of the United Kingdom made it necessary to conserve as much imported fuel oil as possible and to this end experiments were carried out using home produced tar oil as fuel. This oil could not be used by itself owing to low burning characteristics, so Mirrlees developed pilot injection equipment, whereby a small quantity of high grade fuel oil was introduced just before the main injection of tar oil, thus enabling the engine to run on a fuel mixture including some 95% tar oil.

In 1915, attention was called to the need for automatic control of the injection air pressures according to the load on the engine and Mirrlees took out a patent on electrical and mechanical control equipment. the electrical patent covered the automatic control of the air compressor throttle in phase with the load on the main generator. This additional equipment proved extremely popular in service, particularly in multi-engine stations. A further important introduction was that of the floating gudgeon pin, a feature now in almost universal use. Previous to the Mirrlees innovation it was custom to lock the pin securely to the piston. this was, on research, however, found contributory to piston seizure and distortion and with the introduction of the floating pin, permitting axial and rotational freedom, such troubles were obviated.

The problem of accurate lining up of the crankshaft was solved by Mirrlees engineers, who developed one of the first alignment indicators.

During the year 1924 Mirrlees developed a small semi-diesel engine to meet the demand for a light-weight model. this was the "Simplex" engine, having a bore of 12 inches and a stroke of 13 inches, to give 40 BHP per cylinder at 325 r.p.m. Originally this engine was a hot bulb type with external heating lamp, but was latterly converted to a high compression ignition engine. The engine was of the cross head type and a number were supplied for generating station use and flour mill machinery.

Arrangements were made during 1925 to build under licence two-cycle engines of the "Nobel" type. This engine developed 300 BHP per cylinder at 150 r.p.m. with a bore of 22 inch diameter and a stroke of 30 inches. the pistons were oil cooled, and the engines were fitted with rocker arm operated compressors, later changed to compressor drive from the end of the engine crankshaft. Several engines of this type were sent to South Africa for railway workshops and generating stations.

60hp per cylinder In 1926 attention was paid to the development of other enclosed types, incorporating forced lubrication and two models were designed, one having a bore of 12.5 inches and a stroke of 19 inches, developing 60 BHP per cylinder at 300 r.p.m. and the other having a bore of 13 and three quarter inches and a stroke of 19 inches, developing 75 BHP per cylinder at 375 r.p.m. these engines were extremely popular and many sets were supplied as marine auxiliaries for generating  DC current and for power generation on tugs, tin dredgers etc.

Whilst the general development of engines was progressing, Mirrlees were also paying attention to increasing revolution speeds and problems of critical speed. investigations were undertaken on torsional vibration in the factory laboratory. In 1918 the firm's technicians were studying the problems involved long before the advent of the now well known oscillograph. To this day, details of the driven machinery are carefully studied for each engine prior to dispatch.

Around the year 1930, it became obvious that diesel engine design was progressing from the air or blast injection type to the airless or solid injection version and Mirrlees devoted themselves to the problem of the airless injection engine. For several years, both types were produced side by side, but ultimately progress was such that the air injection type engine was superseded.

Ricardo Sleeve Valve During this same period the 'Ricardo' sleeve valve engine attracted attention and Mirrlees designed two engines embodying this patent form of valve gear, one type having a bore of 5.5 inches and a stroke of 6.5 inches, developing 20 BHP per cylinder at 900 r.p.m., and the other with a bore of 17 inches and stroke of 21.5 inches, developing 50 BHP per cylinder at 200 r.p.m. the lower powered unit incorporated a special flange and spigot housing on the flywheel end. this housing was bolted to a similar casting on the electrical machinery simplifying the lining up of  the set, which could then be transported as a complete unit. these units embodied the three point contact, having two bolting faces, one either side of the engine and a central plate under the generator. A similar model without the 'Ricardo' sleeve valves,  was developed during this period. This had a bore of 8.25 inches and a stroke of 12 inches and was designed to develop 20 BHP per cylinder at 600 r.p.m.

UD 8 In 1934 Mirrlees designed a new engine, having a bore of 8.25 inches and a stroke of 12 inches developing 60 BHP per cylinder at 900 r.p.m. this engine embodied the 'Ricardo' comet head combustion chamber. Later, the bore and stroke of this engine were modified to 8.25 x 13.75 and also embodied a Ricardo Comet head combustion chamber which was later converted to an open combustion chamber with the 4 valve cylinder head. this latter unit became the well known Mirrlees 'TL' engine and was made in sizes from three to eight cylinder in line and twelve cylinders vee form, the engine being available in both normally aspirated and turbocharged forms.

H Series An engine of the  larger type, known as the 'HP', having a bore of 13.75 inches and stroke 21 inches was also developed during this period., made in five to eight cylinders in-line sizes, either normally aspirated or turbocharged. In the latter case, the eight cylinder unit has a BSS 12 hour rating of 1,320 BHP at 375 r.p.m.

With the advent of the Second World War, Mirrlees again concentrated on defence production. Over four hundred engines of varying powers were produced during the war years. Some of these engines provided power for radar, radio-location, airfield and various lighting systems for the Air Ministry. War Department requirements were met with engines for ordnance factories, WD stores and mobile generating sets for emergency use at home and overseas. Maintaining the close association which existed with the Admiralty between the wars, Mirrlees supplied many engines for the propulsion of minesweepers, towing vessels and landing craft, as well as auxiliary generating sets for shipboard use. In addition, generating sets were supplied for many naval bases and fleet air arm stations.

Immediately after the war, in 1945, Mirrlees, Bickerton & Day Limited joined the Brush group. After a period of settling in, extensive reorganization began to take place. Over the years the area of the plant had increased to nearly eight acres and of that some 400,000 square feet area was covered. At the end of 1946 machine tools began to be replaced until almost 90% of machine tools and equipment had been renewed.

J Series During 1947, whilst the demand for the 'TL' and the 'HP' range of engines was at it's height, development was taking place of two new types of engine, embodying all of the proven features of previous Mirrlees designs. these were the 'J' and 'K' ranges. Of these new engines the 'J' range with a bore of 9.75 by 10.5 stroke, was made in 3,4,5,6 and 8 cylinders in-line and 8, 12 and 16 cylinders Vee form covering a range of 135 to 2,480 BHP at 600 to 1000 r.p.m. The 'J' engines had a wide duty range since powers and speeds available made these engines eminently suitable for fitting to shunting and main line locomotives, oil field applications, and mobile and semi-mobile power packs in addition to marine and industrial units. A six cylinder in-line version of this engine was first produced during the summer of 1949 and on test completed some 1,650 hours trial running, reaching a maximum of 1,150 BHP at 900 r.p.m., a brake mean effective pressure of 215 lbs/sq inch. This latter power was obtained using a pressure charger fitted with aftercoolers. During the entire period of trial runs on this engine, it was found to function perfectly and no measurable wear had taken place when the engine was stripped down after these tests, to be re-assembled for installation in the factory power house.

Parallel to the development of the 'J' range was that of the larger, more powerful 'K' range in 1950. Development and tests occupied a period of two years and culminated in a range of engines built in 3,4,5,6,7 and 8 cylinder in-line and 12 an 16 cylinder Vee forms. These were available naturally aspirated, pressure charged or pressure charged with intercoolers. The power range covered being 183 to 4128 BHP at speeds from 200 to 450 r.p.m.

The 'K' type engine was totally enclosed, four stroke cycle with open type combustion chamber and direct fuel injection, and of extremely strong construction. Bore and stroke of both the in-line and Vee form engines is 15 inches by 18 inches. Pressure charged and intercooled engines operate in service at brake mean effective pressures 150 lbs/sq inch. Operating at this rating followed extensive test work at ratings exceeding 200 lbs/sq inch BMEP when running at 428 r.p.m.

Right from the start of production, both the 'J' and 'K' ranges of engines proved extremely popular. By the beginning of 1955 more than 650 'J' engines had been produced. The first production 'K' type engines were built in 1951 and over 1,000 engines were produced during the following 15 years.

In addition to the development of new types of engines, Mirrlees developed a new means of producing them. New inasmuch as it was the first time that the principle had been applied to the production of heavy oil engines. The technique of Flow Production made Mirrlees unique at this time and this, coupled with new tooling and plant layout and new engine ranges, made Mirrlees one of the most up-to-date heavy diesel manufacturing plants in the world.

In 1957, the brush Group was acquired by Hawker Siddeley and Mirrlees National was created in 1961 when Mirrlees Bickerton & Day Limited amalgamated with the National Gas & Oil Engine Company Limited.

It was in 1966 when the 1,000th 'K' engine was built, destined for an Australian dredger.

In 1966 came the introduction of the 'K Major', which in 1968 was awarded the Council Of Industrial Design Award, the first internal combustion engine to receive the coveted award.

On 1st June 1969, Mirrlees National Limited and Blackstone & Company Limited, another Hawker Siddeley diesel company, were merged and the Company now traded under the name of Mirrlees Blackstone Limited.

During 1979, the first production engines of the MB275 type were built with a 275 mm bore. It was also in this year that the K Major was uprated to a 400 mm bore engine with a nominal output of 750 BHP per cylinder.

A continuous programme of capital investment and modernisation has enabled production, erection and engine test facilities to remain amongst the most advanced in the world. Numerically controlled machines were first introduced in 1964 with the intention of increasing the flexibility of the shop floor by using machines that were capable of conducting a greater variety of functions. this decreased the number of machines and greatly improved the level of productivity. In the 1960's there were more than 200 machine tools on the shop floor, and by the end of 1987 the figure had been progressively reduced to 148. this was made possible by the introduction of  NC, CNC, ONC and FMS machines.

Production facilities now include two twin-bed Coburg plano millers, one Scharmann horizontal machining centre and an FMS unit capable of the entire machining of cylinder heads. These were introduced as part of the continuing modernisation programme.

the Scharmann and the Waldrich Coburgs are used for the machining of major components on all engines produced at Stockport. This includes bedplates, crankcases, camshaft bores and crankshaft bores. The introduction of these machines has greatly increased machining accuracy on major components, and has also substantially improved productivity. This is due to more simple setting up, less handling, and greater cutting rates.

For many years, engine testing had been done by the side of erection in Bay 10 and later in Bay 14. In 1976 four new test cells were built at the end of Bay 14, and a new 150 ton crane was installed. This enabled the engines to be erected in specially designed engine build stations, and then the complete engine could be lifted into an acoustic test cell. This meant that the test cell could be prepared in advance for an engine, which greatly reduced the time required for the comprehensive testing of every engine prior to dispatch. The capability of lifting the engine in one piece, means that after works test and inspection, the engine can be loaded onto a lorry for immediate dispatch.

In 1984, OMAC ( On-line Manufacture and Control) was introduced into the Company and is used for the monitoring of production and material control. It may be used as a 'window' on the factory for monitoring stock levels, rate of usage of stock, parts and material requirements, and the position of parts in their production run. It is run on a real time basis, and so the information is up to date.

In 1985 design was linked with Production Engineering via CAD/CAM, a Computer Aided Design, Computer Aided Manufacturing system, which greatly improved the production and modification of engineering drawings and production procedures.

In november 1991, the parent company Hawker Siddeley was acquired by the British Tyre and Rubber Company (BTR).

It was then decided that the production of the 'E' engine should be transferred to the Stockport factory, and this led to the company reverting back to the name of Mirrlees Blackstone Limited.

The Foundry, 'E' type Service and Spares Departments, however, remained in operation at the Stamford site.

By mid 1993 the layout of the Stockport factory had been revised to accommodate the arrival of various machine tools from Stamford, and also to adopt the latest cellular manufacturing techniques. The following Islands were therefore created within the factory for production of each group of associated major engine components.

Island C
- Bedplates, Columns etc.
Island W
- Connecting Rods
Island Q
- Prismatic Parts
Island G
- Pipework
Island R
- Valve Cages
Island X
- Cylinder Liners
Island V
- Levers, Gears, brackets etc
Island Y
- Turned Components
Island Z
- Cams, Pistons and Cylinder Heads

During the early 1990's environmental considerations were of higher importance and therefore reflected in customer requirements. Sewage gas was reclaimed for k Major power generation in the City of New York and a t Magden Water Treatment Works, London.

The de-regulation of the Electricity Supply Industry led to numerous market opportunities often employing combined heat and power (CHP) principles. An example of these technologies being the project at Manchester Airport where 2 x KVP12 Majors used natural gas in their cogenerator plant.

A site at Brogborough, Bedfordshire used land fill gas to power 1 x KVP16 producing 6.9 MW which was sold to the Eastern Electricity Board.