U.S.A. EXPERIENCE BENEFITS BRITISH USERS.
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A New Six-cylindered International Passenger Chassis, which has Already Been Tried Out in America,. Placed on the Britis Market.
APERUSAL of the present manufacturing programmes of many of the prominent commercial vehicle makers is all that is needed to show that they realize the need for different types of chassis to meet the special factors encountered by vehicles used for goods or passenger transport. Twelve or more years ago the types of chassis available were mostly listed as being suitable for carrying a dead load of a definite weight, and the passenger chassis, as such, was virtually unknown. The travel-by-road movement has, however, grown at such a pace and assumed such remarkable proportions that manufacturers generally now find it expedient to market specific types of chassis for bus and coach work.
It is not now necessary to tread old ground and to reiterate the differences associated with the operation of goods and passenger vehicles, but the fact remains that many of the changes that, of late years, have been effected in design
have had their object the improvement of the chassis
primarily built for passenger service. For example, take the case of the sixcylindered engine. For the moment there ere few passenger models in which such units are employed, but from what we know is taking place in the works of important makers, coupled with the veering of opinion in favour of engines of this description, it may not be long before buses and coaches—except, perhaps, those of the smallest sizes-.--arc propelled by such units.
Furthermore, these developments are not confined to this country, but are taking place in all the chief motor-producing countrks of the world. Support for this statement is to be found in the latest chassis to be marketed in this countey by the International Harvester Co., of Great Britain, Ltd., 259, City Road, London, E.C. This is the International SL36, incorporating a six-cylindered engine in its design, which has been built expressly for passenger-carrying. Although new to this country, this chassis has been on the American market for some time past, and has given proof of its all-round capabilities to a large number of users in the United States. It is for this reason that the company handling the chassis in Great Britain feels that it has a good proposition to put before users or potential users, particularly as the chassis is marketed at the reasonable figure of £565, and a 22 to 26-seater saloon bus can be obtained B36 for an outlay of about £850, according to class of body used.
The six-cylindered engine is of International make, and in its design the feature of accessibility has been kept will to the fore; no better proof of this could be found than in the position of the magneto, which is carried on the off side on a bracket above the generator. The cylinders are cast en bloc and the head is detachable—further evidence that the design conforms with modern practice. The cylinder block is of the L-headed pattern, and the intake and exhaust manifolds are on the near side, the Zenith carburetter being directly below the centre of the inlet manifold.
The crankshaft is a drop forging in carbon steel, and is of substantial size. It is 21 ins. in diameter and is supported in four large bronze white-metal-lined bearings. From the specification we gather that the projected area of the bearing surfaces is 18.5 sq. ins., and this, coupled with a relatively short distance between the bearings, gives rigidity and a freedom from that disturbing factor—periodic
vibration. The crankshaft is drilled to provide for lubrication of the bearings.
The full force-feed lubricating system is Used, and the gear-type oil pump is secured by two studs to a pad on the intermediate beating cap, being driven by the distributor shaft. The lower part of the pump is always immersed in oil, and requires no priming. The lubricant is drawn from the sump through a strainer and is pumped to the main bearings through copper manifolds attached to the main-bearing caps. A centrifugal pump is used for circulating the cooling water, and this is situated to the rear of the generator, from the shaft of which it is driven. The radiator has a large cooling area, and, following usual International practice, is of the fin-and-tube pattern.
The engine is carried at three points in the frame, the support at the rear of the unit being provided by a banjopattern pressed-steel cross-member. Before passing on to the transmission we mast mention that the engine has a bore of 31 ins, and a stroke of 5 ins., it Treasury rating being 25.3 h.p. It develops 50 b.h.p. at 2,500 r.p.m.
From the engine the power is taken through a clutch of the single-disc dry-plate type to a three-speed-and-reverse gearbox, which form a unit with the, engine. The clutch requires no adjustment other than to give pedal clearance, as wear of the friction facings is automatically compensated for by pressure springs. A housing protects the clutch from the ingress of dust and dirt. The transmission is bolted to the bell housing of the engine, and can be readily removed.
From the gearbox an open two-piece propeller shaft carries the drive to the rear axle. Its three universal joints are oil lubricated, and a central bearing for the first section of the shaft is provided in a stout cross-member just ahead of the centre flexible-fabric joint.
The rear axle is of the spiral-bevel type, in which the driving shafts are contained in a vertical banjo casing with squared ends ; these are machined for receiving the spring seats. The axle housing is so arranged that the differential and driving gear can be freely withdrawn, and the back axle of it is enclosed by a stamped steel cover. The front axle is of the reversed Elliott pattern.
The designers of the chassis have wisely given special attention to the question of springing, and, in addition to the usual semi-elliptical assemblies at both front and rear, supplementary quarter-ellipties are used at the rear. There are ten leaves in the usual spring assemblies at the front and at the rear, the former being 3 ft. 6 ins, long and the latter 4 ft. 4 ins. long. In order to damp out rebound shocks, substantial rubber blocks are used in conjunction with the rear suspension. The auxiliary springs at the rear extend from attachments below the ordinary rear brackets to pads which are securely clamped to the bottom of the axle, and play an important part in giving good riding comfort.
Both hand and foot brakes, which are of the internalexpanding type, take effect on large-sized drums in the rear wheels. The total width of the braking surface is 4 ins. and the diameter of each brake is nearly 16 ins. Easily removable shields ensure that the friction material is kept free from mud and water. To prevent the possibility of freezing-up of.the brakes, Alemite oilers are provided. Disc wheels with demountable rims constitute standard equip. meat, and they carry heavy-duty pneumatic tyres of 30-in. by 5-in, dimensions, twins being used on the rear wheels.
The specification shows that the regular equipment of the chassis includes Remy electric lighting and starting apparatus, power-driven tyre pump and vacuum-feed petrol supply from a fuel tank carried at the.rear between the chassis frame members. It should he mentioned that the pressed-steel frame members are '6716 ins, deep, the channels being perfectly straight, except where they are upswept to clear the back axle. The frame is stiffened by the use of nine cross-members.
The following are some of the outstanding diniensions of the chassis :—Height to top of frame (with capacity load), 2 ft. 01/411 in.; length of chassis overall, 18 ft. 11rins.; length from dashboard to end of frame, 13 ft. 10i ins.; track, 4 ft. 8 ins.; turning radius, 29 ft.; and overhang, 3 ft. lot ins.
From an inspection of the chassis we can certainly say that it appears to meet the various requirements of useri, in this country (it is, of course, arranged for right-hand control), and, since it has the backing of one of America's foremost makers and is handled in this country by a company which is in a position to meet service and spare parts needs, it should attract much notice.