The Editor writes of superchargers, twin o.h. camshafts, dry-sump lubrication, and all-independent suspension
No matter what his personal car, the enthusiast never fails to take kindly to the type of sports car which has something out of the ordinary under its bonnet. To specify just what is meant by an engine of “advanced design” is not easy, although it is reasonable to say that its ultimate form is represented by the twin o.h.c. supercharged power-unit. On the other hand, the 328 B.M.W. engine, for instance, would be held by most people to be an engine of advanced conception, although certain quite touring, outwardly uninspiring engines have been constructed with two overhead camshafts whereas, strictly, the B.M.W. is merely a push-rod unit. Perhaps the definition of what I have in mind is best met by an engine the construction and finish of which appeal to those who lift the bonnet which covers it, the design of which shows more inspiration than that of quantity production s.v. or push-rod o.h.v. units, and which endows the car into which it is fitted with performance equal, usually superior, to that possible with engines of lesser conception and allure. You know the sort of thing I have in mind and you are doubtless all turning over the names Bugatti, Alfa-Romeo and Maserati on the tips of your tongues.
For that very reason I have dug out some pictures of specialised British sports cars and asked that they form a double-spread in this issue – which is the nearest we of Motor Sport get to producing a Christmas number. I know that Bugatti, Alfa-Romeo and Maserati have produced very beautiful and well-tried examples of just the sort of twin o.h. camshaft, supercharged engines we have in mind. I know that the cars illustrated in our middle pages mostly did not last long and were in very limited production, which could quite well have been because there were snags of one sort or another – that the bugs were not properly gotten out, as our American allies would aptly express it. Nevertheless, I do not think we should scorn these cars. They pointed the way, they showed that Britain could produce engines that were real engineering jobs and not tin cases of apologetic machinery, and they serve to remind us that the continentals did not have things all their own way in this specialised field. Whether there will ever be a market for such cars again – cars which, of necessity, have to be largely hand-assembled and which need engineer-attention all their life – is another matter. Indeed, the limitations of the market probably did more than the bugs to kill those examples which were extra-short-lived. Against which, of course, the 2-litre Aston-Martin and the Alta lived successfully up to the outbreak of war.
Let me explain that this portrayal of British sports cars has been done in a sort of premature Christmas spirit and within the space limitations prevailing, otherwise I should have included certain other cars, such as the Q-type or K3 M.G.s, “Shelsley” Frazer-Nash, Rapier, Beverley-Barnes, etc. I feel obliged to refer in the text to the Triumph straight-eight because this is so typical of what I have in mind, although no photograph of it has come to hand.
The Triumph “Dolomite” straight-eight came along in time for the Show of 1934, and on the eve of the Exhibition the late Brian Twist proved on Brooklands that this startling car would exceed 104 m.p.h. I always recall Twist’s remark, after several times reaching 85 m.p.h. on the run to Brooklands, that “We were filled with fresh air and ready for anything” – it has a pleasant ring these days, when eyesight and health are severely stressed most of one’s time in the stuffiness of offices, and by the nerve-strain of transport in public inconveniences. The original “Dolomite” was certainly a motor-car, for it did a standing 1/4-mile in 17.8 sec., a flying 1/4-mile at 102.47 m.p.h., and lapped Brooklands at 98.23 m.p.h. It also got up the Test Hill in 8.4 sec., and pulled up from 30 m.p.h. in 24 ft. The straight-eight engine, of 60 by 88 mm. (1,990 c.c.) ran up to 5,500 r.p.m. and developed 140 b.h.p. It had twin o.h. camshafts driven from their middles by a gear-train, a la Alfa, and the crankshaft had ten plain bearings, the big-ends also being white-metal. The cylinder blocks, in two pairs of four cylinders each, heads and pistons were of R.-R. Hiduminium alloy, and crankcase, valve covers, etc., of electron. Nitrogen-hardened cast-iron liners were shrunk into the cylinder blocks. The valves were set at 90º and had three springs each, the plugs were masked, and each cylinder had its own exhaust oft-take. Pump cooling was used and lubrication was of dry-sump type, with a ribbed three-gallon electron tank between the dumbirons. The engine was supercharged at approximately 10 lb./sq. in. by a Roots blower set low down on the oft side of the crankcase and gear-driven. It drew from a twin-body Zenith carburetter, and there was choice of coil or magneto ignition. The compression ratio was around 6 1/2 to 1. In unit with the engine you had a Wilson pre-selector gearbox with the delightful ratios of 12.4, 7.4, 4.92 and 4.0 to 1. The gearbox had an electron casing, was lubricated by a double oil pump, and had needle-roller bearings. The chassis, measuring 8 ft. 8 in. by 4 ft. 6 in. between the contact points of its 19 in. by 5 1/4 in. Dunlop Forts, had 1/2-elliptic suspension damped by hydraulic shock-absorbers, dual at the rear, steering asking only 1 3/4 turns, lock to lock, and Lockheed brakes with 16 in. ribbed drums of electron with steel liners and R.-R. alloy shoes. There was a special means of adjusting the brake clearance by .025 in. at a time. That, then, was the Triumph “Dolomite,” to sell at £1,125 as a 2-seater. The chassis weight was given as 14 cwt., and the complete car as 18 cwt. The Triumph Company underwent a change of policy soon after its introduction, and very few were built, but it will be remembered that Tony Rolt ran one at Donington some years later, before he became one of our foremost E.R.A. drivers and, subsequently, a prisoner of war in Germany. Habershon and Parnell have two others, the former’s developed by High Speed Motors.
About the same time the 1 1/2-litre Squire came into being, at the factory at Maidenhead, where G.W.K. and Marendaz cars were once manufactured. The engine was basically an Anzani design, of 69 by 100 mm. (1,496 c.c.) It was supercharged at 10 lb./sq. in. by a David Brown or Marshall Roots blower driven from the crankshaft and drawing from an S.U. carburetter. The compression ratio was 6 1/2 to 1 and 100 b.h.p. was developed, the engine running up to 5,000 r.p.m. The steeply-inclined valves were operated by twin o.h. camshaft via tappets, the camshafts being gear-driven. The crankshaft ran in four white-metal bearings and the lubrication system incorporated a ribbed cooler and a two-gallon supplementary oil supply float-fed to the sump. Ignition was by coil and cooling was by twin pumps driven one from the forward end of each camshaft. 14 mm. masked plugs were used. The gearbox was again a Wilson pre-selector, and the chassis used 1/2-elliptic springs, hydraulically-damped, and Lockheed 16 in. brakes, and had automatic lubrication. The Squire was made in two chassis lengths, the short chassis costing £950 and the long 2-seater £1,250. The Squire would do 100 m.p.h., and when Motor Sport tried a long 4-seater with 15,000 miles to its credit, under difficult conditions at Brooklands in 1937, it clocked 93.75 m.p.h. over the flying 1/4-mile, screen up, while in 1935 we recorded 100 m.p.h. and 10-60 in 10 sec. with this model. Some 20 m.p.g. was attained, with acceleration of the 0-50 in 10 sec. order. The short chassis measured 8 ft. 6 in. by 4 ft. 6 in. and weighed about 15 cwt, and the long 4-seater weighed about 22 1/2 cwt. The gear ratios were 16.15, 9.5, 6.25 and 4.25 to 1, but certain cars apparently had a 3.8 to 1 axle ratio.
Production ceased fairly soon after the car’s introduction, and Adrian Squire was killed by enemy action early in the war. Those examples still in existence, however, show the Squire to have been an honest attempt to market a car of modern conception and high performance.
Next we have the Atalanta, built near Staines, and in production up to the outbreak of war. When announced, it comprised 1 1/2-litre and 2-litre versions with an entirely new o.h.c. engine, chiefly notable for having three valves per cylinder, while supercharged versions had a Centric or Arnott blower clutch-controlled by the driver, yet still contriving to suck from the carburetter, involving complex induction arrangements. These technicalities were, even so, overshadowed by the chassis features, for all wheels were sprung independently with coil springs, and there was a Cotal electric-charge epicyclic gearbox.
Eventually the makers put in V12 Lincoln “Zephyr” motors, but the brilliant suspension was retained. Miss Wilby introduced the Atalanta to competition motoring, and at least one of the earlier cars has been in use during the war, while Nixon is having a Talbot engine installed in such a chassis.
The 2-litre “Speed Model” Aston-Martin is the least specialised of the five cars I have chosen to include, having but a single o.h. camshaft operating only moderately-inclined valves, and scorning forced induction. Yet it is one of the most satisfactory and successful, and certainly does not lack performance, as “Two-Point-Six” reminded us in his article of last October, over which controversy still rages. Bertelli introduced the modern conception of 1 1/2-litre Aston-Martin in 1927, and the Feltham works turned these excellent cars out steadily almost up to 1939. But in 1936 the 2-litre made its debut, and just before the war it rather overshadowed the 1 1/2-litre. Normal versions were of more sober design, but the “Speed Model” retained the characteristic dry-sump lubrication system and had quite a high compression ratio, and two S.U. carburetters. A “plain” gearbox was used in this instance but with satisfyingly close ratios-4.4, 6.11, 8.33, and 11.38 to 1. When Motor Sport tried a private owner’s car in May, 1938, speeds of 75 in 3rd and approximately 100 m.p.h. in top, on the road (and not with the super-streamlined body) were easily attained, while the engine ran very cool and gave about 19 m.p.g. at ordinary speeds. The chassis cost £695, and ignition was by Scintilla “Vertex” magneto. Dick Seaman’s T.T. lappery with this car live in the memory to this day.
We conclude this survey with the Alta, Geoffrey Taylor’s famous child. The first 1,100 c.c. car was built by him as a hobby and so took the fancy of enthusiasts when they saw it perform in M.C.C. trials, that he went into limited-output production at the works at Tolworth, off the Kingston By-Pass. 1 1/2-litre and 2-litre cars followed, all with 4-cylinder twin-o.h.c. engines and E.N.V. pre-selector gearboxes in that wonderfully low chassis sprung on 1/2-elliptic front, and 1/4-elliptic rear, springs. Invariably the engines were supercharged with Taylor’s own Roots blower, and in this form the 1,074-c.c. car did something like 86 in 3rd and 105 in top on an axle ratio of 4.6 to 1, while it sold for £498, and gave 25 to 28 m.p.g. The 1 1/2-litre blown Alta was claimed to do 110 m.p.h. on a 4.1 to 1 axle ratio, and nearly 100 m.p.h. in 3rd, while the supercharged 2-litre car was capable of about 120 m.p.h. and cost £575. We have illustrated it in racing trim, which is perfectly permissible, for Geoffrey Taylor was one of the very few persons to offer genuine racing cars for sale “over the counter” in this country. How well they performed is nicely evidenced by his capture of the course record in the Brighton Speed Trials with a 2-litre car.
That, then, constitutes the cars in our centre-page picture gallery. The “Dolomite” Triumph, the Squire and the “Speed Model” Aston-Martin may not happen again; the Atalanta and Alta we shall hope to see on the post-war market. Whether such cars will be wanted in such specialised forms in sufficient numbers in this country after the war to justify them as a commercial proposition remains to be seen. The future will doubtless be bound up with better independent suspension, streamlined bodywork, and light-weight construction, enabling moderate-output engines to present economically a highly satisfactory performance. But there is every reason to suppose that specialised engines will continue to give a still better performance, all other factors being equal. Such engines will cost more, will need more expert servicing, and will make their presence evident, but I, for one, hope that we shall still number amongst us enthusiasts to whom this sort of thing will seem worth while. You can make a very sporting-looking car to-day and give it a foolproof and exciting performance by installing a large motor of quite straightforward design and construction, for example, a big Yank. But to my way of thinking that is only half a car, and does not savour of the real article until you have substituted something of the blown twin o.h.c., light alloy sort under its bonnet and rehashed the other vital parts of the chassis to suit. In its favour, one may say of the latter type of engine that you should be able to about halve the capacity and yet gain some 20 m.p.h., with other performance improvements in keeping, and for the same fuel consumption. As the better behaved amongst such engines no longer call for repeated plug-changes and a drop into 3rd below 25 m.p.h. or so, there is every hope that they will retain their place after the war. And so I present the centre-page spread to remind you that this country can produce this sort of engine, if she wants to.