W ID I,’ C I* A 11 C liii CAUS?

Report of Problem No. 15.

WELL, last month’s picture proved to be the most difficult puzzles of the whole series. It is not to be wondered at, for few people can possibly have seen the actual car in the photograph. If you had happened to be at Le Mans in ;921 you would have seen it winning the French Grand Prix in the hands of the late Jimmy Murphy. Yes, it was none other than the famous Duesenberg. Out of the many entries received only three were correct, and the first of these to be opened on the 15th of last month was that submitted by : Mr. J. Keeling, Barn House,

Sutton Coldfield.

to whom we have sent our cheque for one guinea.

The remaining solutions were shared by the following makers :—Alfa-Romeo, Rolland-Pilain, Cummins Special, Sunbeam, Fiat, Delage, Frontenac, Panhard et Levasseur, Peugeot, Bugatti, Bentley, Lorraine and Miller. We are indebted to Mr. Robert A. Waddy, who sent us the photograph, and who was intimately connected with the tuning of the car, for the following interesting details. Mr. Waddy writes :— The Duesenberg was approximately 3-litres in engine size. It had a single overhead camshaft, above which was mounted the rocker shaft operating the three valves (two exhaust and one intake per cylinder) of the eight cylinders. The rockers had rollers running in contact with the cam, and had no means of adjustment for clearance except by bending the fingers of the rocker itself with a special tool provided by the Factory, a method I have never heard of before or since. The rockers were made of some very special steel, and seemed to put up with this treatment in definitely. They never bent in practice, in spite of two very heavy valve springs. The exhaust rockers were hollow and oil from the hollow rocker shaft passed down the

hollow rocker fingers in a flood, whence it flowed down a vertical duct between No.

4 and No. 5 cylinders to the dry sump, after which it was returned to the five gallon oil tank under the passenger’s seat. ” The valves were in a roof-top cylinder head of about I JO degrees, witb the alumin ium alloy piston-top not square with the wall, but at an angle slightly facing the exhaust side. The connecting rods were tubular, very beautifully made. A six throw crankshaft was used. It was mounted in three mains, ball-bearings be

ing used each end and an enormous bronze bush seven inches in diameter, shaped like a wheel with spokes, the shaft bearing in the hub, in the centre. ” Other details were four Miller carburetters; Defeo coil ignition with two breaker arms, very conveniently situated between the two middle carburetters ; a 3-speed gearbox with control ball change, giving 4, 5 and 8 to t, with 13/52 ring geared and pinion. Alternative back-axle ratios could he used up to 15/52. The

peak was 3,500 r.p.m., with 3,600 as maximum safe revs. The four-wheel bralfes were hydraulic, operated by a piston and cylinder surrounded by the reserve tank. When through leakage or other causes the fluid in circulation got low, the top of the piston went below a port in its cylinder and fluid was drawn in on top of it. As it ascended this fluid passed through the piston by a valve similar to the inlet valve in an old Gnome rotary engine, and thus into circulation. The fluid we used was

glycerine and water. It is possible to discern this apparatus underneath the car below the steering wheel. The piston was stationary, only the cylinder and container being moved up and down by the brake pedal. ” The car, after winning the French Grand Prix, went back to America, and Murphy raced it for the rest of 1921 with great success. In 1922 it had a Miller motor substituted for the one in the photograph and won the Indianapolis 500 as the Murphy Special. In 1923 the original

motor was put back, and the car was sold to the man in the photograph who sliced it in two and cut out 12 inches of length. It is possible on the original photograph to see where the chassis is welded, immediately in front of the forward back-spring hanger. The car was then raced on the dirt tracks of New York State and Pennsylvania with a fair measure of success, though by this time the block and head had warped, and it seemed very difficult to get a gasket to abstain from blowing, there not being sufficient metal left for a re-face.

” The car was extraordinarily free from plug trouble, and would burble indefinitely without oiling up and without getting hot. With no fan it took nearly half an hour’s burbling to get the engine and oil hot enough to open out or test anything—so much so that we made an electric oil heater to put in through the oil-filler cap to warm up the oil in the garage before even starting the engine, as we found it very difficult to persuade the Miller carburetters to idle without being unduly rich, which used to soot the plugs but not oil them.

” It had eight Hartford shock-absorbers fitted, the springs being very heavily corded as well. Murphy had a theory of using slackened off shockers and retaining the cording, but the cording was so much trouble to look after that we later scrapped it and relied on the shockers alone.”

Rules for Problem No. 16.

x. Write your name and address and solution in block letters on a plain sheet of paper.

2. Send it in a sealed envelope, marked “Competition,” to “Motor Sport I) (1929), Ltd., 39, Victoria Street, London, S.W.x.

3Entries must reach this office not later than August x5th, and a prize of one guinea will be awarded to the sender of the first correct solution opened on that day.

4. More than one coupon may be included in one envelope.

5. No letter must be sent with the coupon.

6. Employees of “Motor Sport” (1929), Ltd., are not eligible to compete.

7. The Editor’s decision in all matters relating to the Competition is final.

Send Us Your Picture Puzzle!

A prize of half-a-guinea is offered every month for the photograph used in this competition. The picture on this page was submitted by Mrs. P. C. Oxenden, 8, Brelade, Jersey, C.I. to whom we have sent a cheque for that amount.

If you have a photograph in your collection which you think would puzzle readers, let us have a look at it. It may be worth half-a-guinea ! A modern sports car taken from an unusual angle, an old sports car, little-known, or an old type of racing car, they all offer scope for different puzzles.

Incidentally, photographs submitted must be actual photographic prints, not cuttings from newspapers, from which it is impossible to make printing blocks.