SPORTING CARS ON ROAD AND TRACK. THE 20/70 H P. CROSSLEY.
By RICHARD TWELVETREES.
RECOLLECTING the wonderful performances set up by Mr. Leon Cushman with his very fast Crossley at Brooklands, I was only too glad of the opportunity of submitting a similar chassis fitted with a standard four-seater body to a test for the purpose of contributing an article to this series.
Since its introduction the 20/70 Crossley has been regarded as one of the finest examples of its class and the model, whilst ranking in the Sports category as far as performance is concerned, is particularly interesting from the viewpoint of the owner who delights in fast touring, as its speed is combined with a degree of comfort that would be difficult to surpass.
Immediately a car is catalogued as a Sports Model, one is apt to conjure up pictures of elaborate tuning operations and the need of frequent adjustment as a part of the price one has to pay for sheer speed, but whilst it has a guaranteed Brooklands speed of 75 miles per hour, the standard Crossley Sports possesses all the gentle manners of those designed to give a comparatively low maximum speed.
Simple and Straightforward Design.
• As far as details of design are concerned, the chassis reveals none of the complications one expects to find on a car of high performance. Externally, the engine has all the appearance of a touring car power unit, and on lifting the bonnet one might well be surprised that so simple looking an engine should be able to give so high an output. The latter point is just one of the most interesting features of the car, which in many ways is one of the most astonishing vehicles I have handled. It looks for all the world as if the designers had set out to evolve a specially substantial touring model, only to find the machinery had become inoculated with speed. I should think the tester who took the first chassis out of the
Gorton factory had the surprise of his life when he put his foot right down for the acceleration test.
To-day, after having driven the 20/70 Crossley for over 500 miles, I am still bewildered to know where all the power and ” pep ” comes from. If the engine were fitted with four valves per cylinder, actuated by an overhead camshaft and fed by two or three carburettors, with magnetos in duplicate, one could understand its liveliness, but none of these complications exist. On the contrary, the engine seems quite content with its side valves, single carburettor and other perfectly normal features.
The four-cylinder engine measures 90 mm. bore by 150 mm. stroke and has a cubic capacity of 3,705 c.c. It is quite obvious that a great deal of attention has been paid to the refinements of engine balance and the aluminium alloy pistons are designed to eliminate slap at all engine speeds. The lightness of the reciprocating parts, as well as the perfect balance of the rotating components, accounting to a large degree for the extraordinary flexibility and power of the engine.
Another secret of the efficiency appears to lie in the shape of the special tulip valves, in conjunction with the careful design of the ports, and I can only assume that special care has been paid to polishing the latter to give an absolutely unrestricted passage for the gases. The valve timing is rather interesting and though the modifications from strict standard practice are very slight, they appear to be admirably suited to the design of the engine. Apart from these details, which are not anything out of the ordinary, there seems to be nothing which accounts for the remarkable performance of the engine. Four speeds are provided by the side controlled gear box, which is a separate unit carried on a sub-frame,
and the ratios are as follows :—First gear, 12.5 to 1; second gear, 7.93 to 1; third gear, 5.17 to 1; fourth gear (direct), 3.33 to 1 and reverse 10.36 to 1.
The high top gear probably accounts for the deceptive running of the car, for when travelling at fifty miles an hour, the engine appears to be idling in a most unconcerned fashion.
The 27/70 Crossley in Traffic. On taking over the car from Messrs. ‘Crossley Motors, Ltd., .Service Depot in Westminster, I was prepared to spend a quarter of an hour in becoming Acquainted with the controls, especially as the time coi.n.cided with the
rush” hour traffic. There must be some little tricks, I thought, with an engine possessing so much power. But no ! It seemed to behave in quite a sedate manner and took the car along on top gear without the least exertion.
I could not help contrasting its demeanour with that of the Bugatti, which I took from the same Depot, for whereas the latter bustles one into a particular style of driving, the Crossley exerts an entirely different kind of personality—for nothing will persuade me that cars have not personalities of their own. It took some little time to get a really clean change of gear and the box differs from some in that the silent change can only be obtained if the conditions are quite
correct. One cannot flick the gear lever about from gate to gate irrespective of engine and car speeds, which is not altogether a disadvantage, and if the change is a wee bit on the heavy side, one can forgive the designers as they certainly provide a set of gears of such generous proportions as to promise everlasting wear.
By adjustment of the clutch stop, however, one can procure an easy change to suit individual requirements, and as an example Mr. Cushman’s car is so regulated as to render” snap” changes quite simple. Should the driver happen to like driving almost continuously on top gear, the Crossley engine offers no objection and will trickle round without a murmur, and
even though the top gear is so high one might well suppose that the bonnet concealed an eight-cylinder engine, instead of a modest four.
By using the gears in the approved fashion, however, one finds that the engine will rev, up with marvellous rapidity and the car gets into its stride the instant the accelerator is touched.
If ever a car possessed a dual personality that car is the 20/70 Crossley, for it can be all things to all men. For the person who wants to amble about the country, up and down hills on top gear, it is as attractive as to the sporting driver, whose gear lever is seldom still and whose foot is never far away from the floorboard.