HTN 57 – Pre-war National Engine continues to provide power at Hoekfontein Farm

Founded by Henry M. Bickerton, the National Gas Engine Company Limited was established in 1890, with the production of gas engines to an improved Otto design it’s prime objective. Henry Bickerton was no stranger to the world of the i/c engine, having previously been involved with Mirrlees-Bickerton & Day, builders of the Mirrless diesel engine.
Thos early engines were well received, to the extent that within a short period engines were being produced in a wide range of sizes from 2hp to 160hp. It should be noted that power ratings were quoted for operation on good quality coal gas.

Under normal circumstances, The National Gas Engine Company would supply engines fitted with twin flywheels and centrifugal governors. There were, however exceptions to this rule. The small F-Type (1hp) and J-Type engines (2hp) were fitted with a single flywheel, while at the other end of the scale, the ZC model (160hp) cam out with a single large flywheel and out-rigger bearing.

Where an engine was supplied for generating purposes, single or twin extra-heavy flywheels would be fitted. In such instances the prefix letter “E” would appear after the model letter i.e. LE, ME etc. The model “F” engine differed from the general specification in that it was fitted with an enclosed crankcase, allowing an oil bath lubrication system to be used.
During this early period, engines were equipped with continuous hot tube ignition, with the tubes made of porcelain. Engines of 34hp and upward could be supplied with self-starters at an extra cost. In keeping with other manufactures, The National Gas Engine Company introduced a line of oil engines in the late 1890’s and by mid 1904 these were being offered in sizes from 2 to 30bhp.

By 1905 a range of heavy-duty engines were being produced in single and twin cylinder forms. The twin-cylinder models, built up to 250bhp, were designed with a side-by-side layout, whereby should one of the cylinders become inoperative for any reason, the piston and conrod, etc. could be removed and the engine put back into service while repairs were effected.

This was something not possible to twin-cylinder engines built on a vis-à-vis (horizontally, opposed) layout.

While The National Gas Engine Company found production moving towards the larger industrial type engines, they did not forget the needs of the small power-user, for in 1906, the “K” Type range of horizontal petrol engines was introduced.
Offered in five sizes from 2 to 9 bhp, these engines were equipped with electric ignition in the form of a low-tension magneto and igniter. On later models a high-tension Hills Magneto and spark plug were fitted.

A further change occurred around the mid 1920’s when the popular Wico EK type magneto was introduced in place of the Hills magneto.
For industrial applications a range of tandem gas engines were made available, and by 1912, these had appeared in sizes from 300 to 1, 500bhp. To meet customer requirements, The National Gas Engine Company were prepared to set up their larger engines to operate on town gas, producer gas, blast furnace gas or Coke oven gas, the choice of fuel being dictated by availability and cost.

In late 1912, the company were reported as building 270 engines per month in the 1 to 1, 500bhp power range. Of these smaller models had overhung cylinders, while the larger models employed a girder-bed with cylinder support. Engines up to 185bhp could be had in single-cylinder form, while the larger models were offered in multi-cylinder forms, either horizontal or vertical.

During the 1912/19 periods, the majority of crankshafts used by The National Gas Engine Company were purchased from Mitchell Shackleton & Co. and the letters “MS & Co.” plus two digits, indicating the year of manufacture were stamped on the side web.
One of the more unusual engines built by The National Gas Engine Company was a vertical open-crank petrol/paraffin model. Very little has come to light regarding production of this engine and few are believed to have been built.

Around 1929, a small, horizontal, enclosed-crank petrol/paraffin engine was introduced. Developing 2 1/4 to 2 2/4 bhp at speeds of 800/1000rpm, it was offered with either hopper or tank cooling. The ignition was by Wico EK trip magneto or Wico rotary magneto, which was located, somewhat vulnerably, at the rear of the crankcase. The fuel tank, located over the crank actually formed part of the crankcase. A gas version was also offered in which the fuel tank was replaced by a simple cover plate. An unusual feature of this model was that the interior surfaces were painted an orangey-red colour.
Also appearing around 1930 was the model “V” vertical engine. Available in tank or hopper cooled forms; the “V” engine was of typical National robustness. The valves were of a vertical opposed layout, which was not uncommon at that period. However, on the hopper cooled model, the push rod to operate the inlet valve passed through a tube in the water hopper.

In 1932, the company title change to National Gas & Oil Engine Co, and a year later the model LB horizontal heavy oil engine was introduced with the smaller power user in mind. Rated at 10 – 11bhp, the LB featured a fully enclosed crankshaft and was of the cold-starting type. The general-purpose industrial model came with twin-flywheels, while the electrical model (LBE) was fitted with a single heavy flywheel.

Around 1935, the small vertical BS, DS & ID range of engines were introduced. One special feature of these engines was their renewable cast iron cylinder liners.
In 1938 a National dual fuel engine was developed, whereby it could be operated on oil or gas (after starting on oil), with the changeover being instant. It must be said that prior to 1938, while it was possible to have an engine capable of operating on either fuels, the changeover was no easy task, with the service of a fitter being required to make the necessary adjustments etc. In most instances, this involved several days’ work.
Around 1945, the DSH and DSSH vertical diesel models were brought out to replace the older BS, DS & ID engines. While both models employed the same bore and stroke measurements of 4 1/2 & 6in the difference in power outputs was achieved by simply increasing the operating speed. The DSH gave 7hp at 800rpm and the DSSH 9 1/2hp at 1, 100rpm. The DSH engine featured splash lubrication, while the DSSH engine used force-feed lubrication.

In 1949 the Brush Group took part control of The National Gas & Oil Engine Co, a situation that continued till 1961 when they took over completely. From that date, the company started trading as Mirrless National Ltd.
In 1977 Mirrless-National were in turn taken over by The Hawker Siddeley Group, resulting in a name change to Mirrless-Blackstone (Stockport) Ltd.
In 1992 they were still trading under this name, building large diesel engines for ships, locomotives and power stations.