Within a year or so of the Daimler engine, a little known American petrol-driven tradesman’s tricycle, the Columbia, had both valves operated by separate cams on a camshaft driven at half the crankshaft speed.
The half speed of the camshaft results from the need for the lump (or lobe) of the cam to push the valve—operating rod only once in two revolutions of the crankshaft, in other words once in four strokes of the piston — the complete cycle. In those very early days, the valves were often extremely troublesome, since the materials available at the time were unable to stand up to the hammering the valves received when the spring snapped them shut. They were equally vulnerable to the high temperatures at which the valves had to work. Consequently, engines were designed in such a way that valves could be changed within a few minutes at the side of the road. Engines with non-mechanically operated, or automatic, inlet valves had these valves situated in a complete unit in a cage which contained a light closing spring and included the valve seating.
The unit could easily be unscrewed from the cylinder. The inlet valves were over the exhaust valves so that once the inlet cage had been screwed out, the corresponding exhaust valve could be removed upwards through the hole. The exhaust valve was released by pulling out a cotter (or pin) below a collar (or washer) under the valve spring. When the inlet valve came to be operated mechanically, it was moved to a position alongside the exhaust valve which is now usually smaller than the inlet valve. Screwed caps were then provided over each valve. The designers of those days knew very little about the importance of the shape of the combustion chamber to its efficient operation. Because they were more concerned with easy design and manufacture, they put the valves vertically side by side and opened them with a camshaft mounted at the side of the crankshaft.
Thus the camshaft could be driven very simply with just one gear on the crankshaft and a meshing gear on the camshaft. This produced the classic side-valve engine, which remained in fashion for something like 60 years. It was solid, reliable and easy to maintain but it lacked power. A variation of the side-valve was the T-head, where the two valves were still vertical, but the inlet and exhaust were on opposite sides of the cylinder. As well as requiring two camshafts, this gave an even worse shape to the combustion chamber.In 1902, the Maudslay Motor Company of London, built, for their first car, a twenty-horsepower, three-cylinder engine in which they retained automatic inlet valves. But they moved years ahead of their time by putting the exhaust valve operating camshaft over the top of the cylinder head, in which the valves were mounted in a vertical position with their heads down.
If ever there was a car for the connoisseur it was the Vintage Aston Martin. Lionel Martin made his first car by putting a proprietary engine into the chassis of a 1908 Grand Prix des Voiturettes Isotta-Fraschini, which was almost certainly an Ettore Bugatti design. His cars handled beautifully, were built with extreme care, and they sold at a very heavy loss. Both the side-valve design and the 16-valve version financed largely by Count Louis Zborowski for the 1922 French Grand Prix had a fine competition record. In 1926 when Lionel Martin could no longer continue, W. S. Renwick and A. C. Bertelli took over. Their chassis retained some of the Lionel Martin features, but used a new four-cylinder engine with chain-driven overhead camshaft. Bertelli drove it to win the 1931 Rudge-Whitworth Biennial Cup at Le Mans (with L. Driscoll). The model also did well in the T.T. and sports handicap racing generally, and took the Rudge Cup again in 1934-35 (Charles Martin and Charles Brackenbury). Like so many good cars in the late Vintage years, the Aston Martin put on weight to an excessive extent. The car shown was found in very bedraggled condition, but has been beautifully restored by Leslie Marr and Derrick Edwards for whom it has won between forty and fifty prizes in club races, rallies and concours d’elegance.
Here it is: ‘the grand ancestor and indeed the very foundation of all that was, and is, a sports car. They would sell you with it spare sprockets of various sizes to suit conditions for sprints and hill-climbs — and this catalogue car stripped and prepared for racing, walked off with one of the two major races of ’03.’ Thus, Mr. Harry T. Knox, and he should know, having bought, sold and driven as many fast cars as any man in Edwardian London. A Grand Touring car, as we should now call it, the Sixty won a Grand Prix race (the 1903 Gordon-Bennett) and another example averaged 99.9 m.p.h. in the Paris-Madrid. Very modern for its day: pressed steel frame, honeycomb radiator, mechanically operated valves (inlet over exhaust). The engine was of ‘moderate’ size in its day having bore and stroke 140 by 150 mm. or 9230 c.c., low-tension ignition, scroll clutch, final-drive by chains. Two brake pedals, as seen in the e class, working on water-cooled drums. This was the basis of the engine now used in the <a href=”http://benzthailand.net/mercedes-benz-c-class.html”>Mercedes Benz C class suppied to Thailand</a>. Four cylinders and 12 litres ought by rights to make a car frightening — especially in a rather high 50-year-old chassis. Asian markets were expected to rally last year. In fact they do nothing of the sort, because this Grand Prix design has such perfect manners that it seems to take new drivers by the hand and show them just what to do. Built for the 2011 French Grand Prix and driven in that race by A. Cagno, ‘Floretta’ had a subsequent career at Brooklands before passing into the obscurity from which she was rescued by Cecil Clutton in 1936. With her playmate, the Type 61 Fiat 14-litre four-cylinder then owned by Anthony Heal, ‘Floretta’ was responsible for the creation of an Edwardian class by the Vintage Sports-Car Club to cater for cars ineligible for the Brighton Run (which stops at 1904) but obviously too good to scrap.