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of Hazel Grove, Stockport, Cheshire (now Greater Manchester). Telephone: Great Moor 2615. Telegraphic Address: "Economy, 'Phone, Hazel Grove"
See Mirrlees for history -
1840 The origins of the Mirrlees Company date back to 1840, when three Glasgow brothers, Peter, William and Andrew McOnie, set up a firm to manufacture cane sugar processing machinery, under the title of P. and W. McOnie. When J. B. Mirrlees became a partner on the resignation of William (later Sir William McOnie, Lord Provost of Glasgow) the firm became McOnie and Mirrlees.
1889 As the partners either retired or died so the name of the company changed until in 1889 it had become Mirrlees, Watson and Yaryan Co.
1897 A committee was established to study Dr Diesel's 20 BHP engine, as a result of which an agreement was signed whereby the patentee granted an exclusive licence for the manufacture and sale of the diesel engine in Great Britain. The company produced its first engine 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, it was later put into regular service on the company's premises. It is now to be seen in the Anson Engine Museum. 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.
1898 The firm was again reconstructed as Mirrlees, Watson and Co, with Charles Day as manager. It was he who developed engine manufacturing. They supplied the first diesel engine to be installed in a naval ship.
1908 The diesel engine business of the company at Glasgow increased so rapidly that a decision was taken to manufacture diesel engines in a new facility. Charles Day, later Chairman of the Company, went to Cheshire to set up the new factory at a small village called Hazel Grove, on the outskirts of Stockport. With the financial assistance of Henry Neild Bickerton of the National Gas Engine Co, they formed Mirrlees, Bickerton and Day. The factory opened during October 1908 for the manufacture of diesel engines ranging in power from 50 BHP to 750 BHP.
1911 Electrical Exhibition. Diesel oil engine 4-cylinder and 1,600 bhp for driving dynamos on warships. 
1911 Salt works at Weston Point, Cheshire. 
1912 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.
1912 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.
1912 With the increased load demand at Power Stations, Mirrlees next designed a larger engine during the latter part of 1912, which in its 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.
WWI 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.
1914 Engineers. Specialities: sugar machinery, condensing plant, fresh water distilling and evaporating plants. Employees 1,000. 
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.
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.
1925 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.
1925 February 19th. Founding shareholder in Austin Electric Co
1926 In March this year the shareholders of Mirrlees, Bickerton and Day was held in Manchester, in order to sanction a scheme for the company's amalgamation with the already closely allied firm of Mirrlees Watson Co of Glasgow. The two companies were amalgamated.
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.
1927 Air-blast diesel engine and dynamo by Mirrlees, Bickerton and Day of Hazel Grove for Mid-Kent Snodland Pumping Station. Exhibit at Manchester's Museum of Science and Industry
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.
c.1930 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.
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.
1933 Mirrlees, Bickerton and Day was recorded as incorporating Mirrlees Watson Co. Directors were Charles Day, Chairman and MD, Cherles Ker, Henry Cooper Bickerton, William Allinson Dexter, Herbert Thomas Day, and David McHardy Semple..
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.
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.
1937 Listed Exhibitor. Motor Driven Self-priming Marine Centrifugal Pump in operation. Mirrlees-Simplex Circulator Pump for central heating systems. Centrifugal Pumps, for all purposes. Single Stage Split-Casing Pump. Small Motor Driven Pumps. Radial Flow Steam Turbine. Automatic Stokers for Boilers, Central Heating and Industrial Furnaces. Mirrlees "Imo" Rotary Pumps, for oil pressure up to 3,000 pounds. (Stand No. B.420) 
WW2 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.
1944 Producing the Mirrlees-Ricardo diesel engine for marine use
1944 Associated British Engineering, owners of a large shareholding in the Brush Group, acquired for cash the goodwill and assets of the diesel engine business of Mirrlees, Bickerton and Day. A new company was formed to continue the business under the old name. Mirrlees' Glasgow factory was to remain as part of the Mirrlees Co and would continue to operate as Mirrlees Watson Co, manufacturer of sugar machinery.
1945 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.
1947 The assets of two wholly-owned subsidiaries of Associated British Engineering, Mirrlees, Bickerton and Day and J. and H. McLaren, were transferred to Brush in exchange for shares (transaction completed in 1949).
1947 While 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 after-coolers. 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.
1950 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 inter-coolers. 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 inter-cooled 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, in as much 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.
1960 Advert. Imo fuel oil service pumps. Subsidiary of the Mirrlees Watson Co
1960 Advert. Underfeed stokers. Specialists in solid fuel firing. Mirrlees Watson Co of London, Glasgow and Stockport
1961 Diesel engineers, manufacturing diesel oil engines, diesel electric generating sets and diesel locomotives and marine engines. 1,850 employees. 
1961 Engineers and ironfounders. Manufacturers of sugar and pumping machinery and steam condensing plant. 1,200 employees. 
1966 The 1,000th 'K' engine was built, destined for an Australian dredger.
1966 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.
1968 Diesel engine that runs on natural gas. 'Most powerful British dual-fuel engine'. 
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.
The first British diesel engine Mirrlees No 1 now resides at the Anson Engine Museum