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In 1954 I joined the Mini-Motor assembly line. This line was on the north side of the main factory, running west to east. The production area was about 50 foot square whilst the assembly and test area was about 12 feet wide and about 100 feet long. Items like magnetos, sparking plugs, carburettors, ball races and piston rings were bought in but the rest of the parts were made on site.
Pistons were first machined on the inside of the skirt and the bottom edge was faced. Next, locating on to the machines by the inside skirt, the gudgeon pin hole was drilled, then reamed. Thirdly, the piston was mounted on a fixture in a lathe and was held by a draw bar through the gudgeon pin hole; thus enabling the outside, the ring grooves and the crown to be turned to size, using paraffin as the coolant. Pin holes were drilled and pins fitted to stop the two rings turning in their grooves.
Another interesting job was the manufacture of the crankshaft assembly. This was made up of four main parts: the magneto side crankshaft, the driving side crankshaft, the crank pin and the con rod. The two crankshafts were pressed onto the crank pin with the roller bearings and con rod in position. The next operation was to grind the places where the main ball races went on the assembly to the correct diameter and the correct distance between the faces, thus maintaining a fairly tight tolerance. The crankcase halves were machined in the normal way; so too the cylinders, which were bored and honed. All cylinders were bored and honed at Trojans and there was a small section that did nothing else.
Moving on to the assembly line itself, studs were inserted using a hand stud insertion tool and the engines were assembled in much the same way.
There was a test rig against the north wall of the building that contained positions for twelve engines. An engine was put in the fixture and turned by electric motor. After a 20 minute running-in period, the sparking plug was fitted, petrol/oil mixture was turned on to the carburettor and the electric motor was used to start the engine. The exhaust was connected to an extraction pipe. After a successful running period the engine was removed from the test bed, cleaned and the fuel tank bolted on or, if it was an industrial unit, the frame of whatever the customer had ordered was fitted. The completed unit was then passed to Stores ready for dispatch.
On February 28th, 1954 I joined REME to do my National Service, but I kept in touch with Trojans.
[This article was first published in the August 1992 newsletter of the Trojan Owners Club and I am grateful to the TOC for allowing me to reproduce it here.]hr />
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