Les Vingt-Quatre Heures Du Mans
Le Mans, June 11th/12th Dramatic endings are nothing new in motor racing, even if they…
A SINGLE CYLINDER SIZAIRE = NAUDIN
CAR-BREAKERS’ dumps have long exercised over me a sort of horrible fascination. There is something melancholy but arresting about the sight of a relic, once a proud ship of the road, now a mechanical carcase. The bonnet does not fit, the hood is in tatters, someone has parked a lorry engine with a broken crankcase in the back seat, but that little hornpush, which cost the owner so much ingenuity to fit, is still half attached to the steering-wheel. One glances hurriedly at one’s own car, the object of so much affectionate solicitude, and shudders. I had approached this particular scrapheap with no particular ideas of rescue work. I had glanced at one or two derelict sports cars with melancholy interest, and casually inspected the serried rows of magnetos, of every age and type, arranged on shelves in a shed. And then
I saw it . .
” What’s that ? ” I said.
” Ah ! That’s a rare old ‘un,” replied the owner of the dump. ” We used to have that stuck up on a stage by the gate as a sort of house-sign.”
I repressed a shudder, and began a more methodical inspection. Before very long some money had changed hands, four tyres and tubes which would still hold air had been transferred from other derelicts, and my ” new ” car was attached to the Bugatti.
We had forty miles to go, and the driver of the Bug saw no reason to be influenced by special circumstances. His foot became glued to the floor in its usual position, and he remained sublimely indifferent to my agonies on the other end of the tow-rope. The steering of my acquisition had not been lubricated for some time, and it required both hands on the wheel to alter course The foot-brake did not work, and the hand-brake did little more than emit squeals. I shall not forget that tow for some time but at length we reached home and the new car was safely stowed in the stables. I had rescued from the scrap-heap nothing less than a 1908 Sizaire et Naudin. ” What’s that? ” ask the
moderns, impervious to my air of inaportanee. ” Well,” say 1, ” the ancestor of the Sizaire Freres.” Still a blank loo.
” Well, the ancestor of the Sizaire-Berwick.” ” Oh I know, the car that tried to look like a Rolls-Royce.” Poor brothers Sizaire, after all your ingenuity, you are only remembered in one of your less distinguished moments ! Early Days I. think that Georges and Maurice Sizaire, with their partner, Naudin, began
building motor-cars in about x9o5. In that year ” l’Auto ” instituted its afterwards so famous race for the Coup des Voiturettes, but some lunatic strewed the course with nails, and the resultant confusion was such that the A.C.F. declared the race null and void. The next year, however, the race was held at Rambouillet, and was won by an almost unknown entrant, Georges Sizaire, on a Sizaire et Naudin car. (This same race, incidentally, marked the first recorded appearance of a car built by a then equally unknown young man named Louis Delage.) The winning Sizaire-Naudin had a single-cylinder engine of 120 X 120 mm. bore and stroke (1,364 c.c.), giving 18 h.p. at 2,000 r.p.m., or 13.2 h.p. per litre. The next year the rules limited the bore of single-cylinder engines to too mm., with the result that the Sizaires built theirs with a stroke of 150 mm., giving a capacity of 1,178 C.C. At the same time the compression was raised from 4.2 :1 to 4.5 :1, the crankshaft speed was put up from 2,000 r.p.m. to 2,400 r.p.m., and thus the piston speed from to metres per second to 12 metres per second, with the result that the power of the smaller engine was increased to 22 h.p., or t8.6 h.p. per litre.
In 1908 the rules remained the same, but the Sizaires despairing for the moment of increasing crankshaft speed beyond the formidable figure of 2,400 r.p.m. contented themselves with putting the stroke of their engine up to 250 mm., making the capacity 1,963 c.c., and the piston speed 20 metres per second. At the same time the compression ratio was raised to 5 3, and the power developed was 42 h.p., or 21.4 h.p. per litre. The next year Sizaire-Naudin did not compete in the race, which was won by a Lion-Peugeot with an engine of the same
dimensions and approximately the same performance as the 1908 Sizaire. Peugeot, therefore, may be said to have taken up the thread of voiturette development where Sizaire laid it down. From that date onwards till the War the house of Peugeot was busy developing the volumetrically efficient engine, until in 1914 it produced a 21-litre engine developing 8o h.p., or 32 h.p. per litre. In other words, the history of the early Sizaire-Naudin racers is the beginning of the history of the modern highefficiency (volumetrically) engine. Now, perhaps, when you say you have never heard of the Sizaire-Naudin, you will pardon my impatience.
A Single Cylinder 1,500 c.c.
But to return to the car which I had acquired. This was not one of the racers, but a spo:Is model derived from them and possessing all the same main mechanical features, which are interesting enough. The engine of this model, which was known as the 12 h.p., is, of course, a single-cylinder with a bore and stroke of 120 x 130 mm., giving a capacity of 1,470 c.c. (Just ponder for a moment over a 11-litre single!) The bore, incidentally, is the same as that of the Sizaires’ 1906 racer, the stroke a concession to the development which was forced upon them by the limited bore rules.
The piston is, of course, of cast iron, and the big end of the connecting rod is eccentrically mounted between two large flywheels forming the crankshaft. The side exhaust valve is arranged in a pocket at the front of the cylinder, with the overhead inlet valve mounted directly above it and operated by a push-rod and rocker. The carburetter, a Longuemare, is of vertical type and consists of a float chamber and box-shaped jet with four holes, one in each face. Above the jet is a bell-shaped cover, which works as a kind of choke and which can be let down flush with the platform round the bottom of the jet by way of a strangler. There is no throttle, nor indeed any control of the carburetter whatsoever once the strangler has been opened. Though historically out of place, it may be well to say here that in the course of our efforts to get the engine to run properly, we
found that the mixture was much too rich. Now in the induction pipe, between the carburetter and the inlet valve, there is a valve which can be opened by suction against a light spring. It is quite easy to watch this valve working as it is in a cage with large air ports. It was fairly obvious that the only method of curing over-rich mixture was to make this valve open more readily, and indeed it appeared from observation that it was not working to any purpose unless the strangler was closed or the engine speed was high. We therefore spent a morning experimenting by snipping lengths off the spring, reassembling the air valve gear, starting the engine and smelling the exhaust, until its odour was reasonably pleasing.
But without a throttle, how is the engine speed controlled? There is, of course, a spark advance, but for reasons to be explained later this invariably finds itself at full advance or full retard. No, there is far greater cunning in it than that.
Ingenious Throttle Control The of the inlet
The push-rod of the overhead inlet valve is actuated by a sliding profiled cam. One end of this cam is so shaped that it does not allow the inlet valve to close fully, and thus gives a half compression device for starting. Slid along a little, the cam allows the valve to seat, but only gives it a moderate lift, further sliding increases
the lift progressively, and this sliding cam, which is operated by a lever working on a quadrant on the steering wheel, gives, in the words of a contemporary writer, ” a very delicate control of the engine.” The latter rejoices in dual ignition. A make-and-break on the front end of the
two-to-one shaft outside the crankcase controls the flow of current from a 6-volt battery via a buzzer coil. Still further forward on the two-to-one shaft is mounted an exposed gear-wheel which meshes with another on the magneto. The latter, although made by Robert Bosch, is definitely suffering from anno domini, and contributes little to the ignition. The two sparking plugs are screwed horizontallv into the valve pocket, the cylinder-head itself being reserved for a compression tap. Both the petrol and oil tanks are built into the scuttle, the latter feeding through a drip-feed to the crank-case, where the rest is clone by splash. The cooling water circulates on the thermosyphon principle through an ungilled tube radiator with an enormous header tank.
So much for the hearty single-cylinder 1,500 c.c. engine. At the back of it there is a third exposed fly-wheel, and in this is a plate clutch, kept in engagement by a large extension coil spring. Behind that one looks in vain for a conventional gearbox. The fact is, the Messrs. Sizaire and Nauclin had devised a method of direct drive on all three forward speeds. The gear lever, which works on a notched quadrant in the then not unusual way, is mounted on the end of a shaft running across the car, and rotating with it a rack which is mounted on it. This rack engages with a pinion, which thus rotates a jointed shaft running longitudinally to the car, and of which the other end disappears within the differential housing. Here I must admit that I have never taken the back-axle assembly to pieces. Its mechanism works, and there
is something in letting well alone. In consequence, however, I am not quite sure of the exact method employed, but somehow movement of the gear lever imparts both longitudinal and lateral movement to the propellor-shaft. The latter has on its after end three pinions, which mesh in turn with the crown wheel as the propellor shaft is moved longitudinally. As these pinions are, of course, of different sizes to give the different ratios, the necessity for lateral as well as longitudinal movement of the propellor shaft is fairly clear. Not content with containing this mechanism, the back-axle housing also accommodates a differential gear and a brake, operated by a pedal. Just to make the driving problem more difficult, by the way, the brake pedal is placed on the left and the clutch on the right. Just consider trying to change down in moments of stress!
But we have not yet exhausted the mechanical interest of the Sizaire. The frame is of ash, reinforced with flitch plates, and is suspended from the back-axle by quarter-elliptic springs. (A massive tube from the change-speed-differential case to a cross-member of the chassis looks after the torque.) But in front, the cat rejoices in nothing less modern than independent wheel suspension, or ” knee” action ” as it is called transatlantically. The frame terminates in a transverse steel beam, which is rigidly attached at its centre to the centre of a transverse leaf spring. At either end the beam terminates in a guide, which has sliding in it a pillar. The upper ends of these pillars are attached to the ends of the spring, and on the lower ends of the pillars are mounted the short road wheel axles. The beam is thus merely a distance-piece, and each front wheel is free to move up and down independently against the resistance of the transverse spring.
The ” Kent Messenger’s ” Veteran Cars Run last year was for machines built in 1908 or earlier. The Sizaire was therefore eligible, and I determined that it must appear in the event. I must admit that I regarded it as something of a mechanical terror. ” What’s it like? ” inquired the bold individual who had consented to accompany me on the run, ” Well,” I replied, ” the engine usually won’t start ; when it does, as often as not, it runs backwards, with terrifying results. It also kicks ; a mule is nothing to it. If by any chance it does start to run the right way, you know all about it, the spasms of vibration imparted to the car are so shattering.” ” What’s the steering like,” he asked, ” with the independent front springing? ” ” Pretty independent ! ” I don’t think such harsh things about my Sizaire (familiarily known as ” Julius “) now. One gets used to most things. I must admit that however much ingenuity is applied to starting the car, it requires two people to do it. One must use the half-compression, and to have the ignition timed anywhere but at full retard is suicide. As soon as the engine fires, however, someone from the driving seat has got to move the lever so that the inlet valve closes, and gets a good lift, and simultaneously give the spark full advance. The latter operation is effected, by the way, with the aid of a substantial lever, rather like a slender gear lever, just inside the body, to the right of the driver. If the man at the controls acts quickly enough, the engine, once having fired,
starts to thump away merrily enough, and the man at the handle has only to open the strangler and run for his seat.
In any case we eventually got started on the day before the Run, and set off from London for Maidstone. I must admit that the character of the car, and inexperience of it, did not add to the joys of threading one’s way through the London traffic—and the way out to Maidstone is hardly a joyride at the best of times. At last, however, we were on the Sidcup by-pass and had a chance to open out. The inlet valve was given a good lift, the old cylinder thumped away merrily, but the speed of the car was most disappointing. It was soon obvious that Julius was suffering badly from clutch slip.
However, next morning found us with the clutch adjustment taken up, as ready as we could be, and all set in our appointed place in the car park outside Messrs. Rootes’ garage in Maidstone. The first car was scheduled to start at 10.30 a.m., and Julius, who was the youngest of the party, last of all, some quarter of an hour later. Good advice on the part of those who had witnessed vagaries of starting on previous occasions finally persuaded me to set about getting the machinery in motion for the second time that morning, as soon as the first car had left. Of course Julius started at the first pull-up, and who would have dared to stop the engine again after that? So there we were with the engine ticking over on an excessively rich mixture for a quarter of an hour before we ourselves took the road. Little wonder that the car was running a bit sluggishly as we made our way out of Maidstone. A few miles out she began to pick up. Now at some earlier epoch a previous owner had seen fit to drill a hole, about a quarter of an inch in diameter, in the radiator cap. The Sizaire’s added speed was quick to cause a rush of blood to the head, or less figuratively speaking, a rush of water to the header tank, and a scalding flood issuing from the above-mentioned hole in the cap found its mark in the faces of the driver and mechanician. Our subsequent stop was rather hurried, and matters were remedied by plugging the hole with
a branch picked from a roadside tree and a rag. Climbing back into our seats we continued our way, hitting the thirties comfortably, to Ashford where we were soon lost in the intricacies of the town. From this dilemma we were rescued by the timely arrival of an A.A. scout and continued on our way to Tenderden, and the lunch stop. Julius in spite of his hasty preparation,
was proving less of a mechanical terror than I had at first thought. Steering, brakes and engine control were none too bad on the open road, and at a cruising speed in the thirties on top, the vibrations were only pleasantly exhilarating. At Tenterden the cars were the cynosure of an admiring crowd. An i8cs7 Hurtu, according to the programme, had been found with a tree growing through it. An onlooker, noticing our plug to the radiator
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cap, which was admittedly some six inches long, was heard to remark : “I suppose this is the one the tree grew through.”
To cover our confusion we retired to lunch, and an hour or so later, feeling at peace with the world returned to face the second half of the journey. The time to depart approached, Julius’ engine started like a lamb, we climbed into our seats— and the engine died on us. A second time we started it, and the same thing happened, a third, a fourth. By this time the rest of the competitors had long ago disappeared down the road to Cranbrook. We both plumped unreservedly for fuel shortage. The carburetter was reduced to its component parts, the fuel lines taken
down and blown through, quantities of petrol were spilt. We had to confess we could find no obstruction. Disconsolately we attached the ignition. The battery was well up, the coil gave a spark, a change of plug proved no remedy. At this moment salvation arrived in the form of a genius who called for a hammer, with this he dealt the butt end of the external spring on the coil a hearty blow, thus increasing its tension, and presto ! the engine started up, ran heartily, and we were away. Southborough, and the finish of the trial, had to be reached by half past five, and after all these delays we had little time to spare. The road was winding and hilly, and Julius soon began to miss again. Nevertheless we banged along for all we
were worth. Tunbridge Wells at last, and as we thumped along the last bit of road to Southborough, we could not have urged the car on more vehemently if we had been finishing a Grand Prix at 200 m.p.h. And then the final control, and the realisation that we had got in with just five minutes to spare.
The rest of the competitors had already gone off to tea, and after we ourselves had imbibed refreshment, we set off homewards. Not a miss has that engine given from that moment to this. I am glad, Julius, that I do not depend on your services to catch a train every morning. But for the real thrill of motoring you leave half the modern sports cars cold
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