NEW LEYLAND EXPORT RANGE
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ALL new products from that worldfamous concern, Leyland Motors, Ltd., are of interest, and particularly so in the present instance, when they comprise a complete range of new chassis designed especially for export, although it is hoped to have a modified version equally suitable for home use when economic circumstances permit.
During the • war the entire Leyland capacity was engaged in Tank manufacture—for three years no wheeled vehicles were made. The company was thus able to bring out improved designs and to reorientate both its manufacturing and selling policy if it so desired.
The general policy had been to build for home users and adapt models to meet overseas needs. Seldom were vehicles designed basically for export, but the post-war policy was to concentrate on the overseas market far more than before and build separate vehicles for this.
Fine Post-War Range Early in 1945 came the military Hippo, with 7.4-litre engine. Then it prepared to make its first post-war passenger chassis, and designs were in hand for a range of heavy-duty. lorries for home and super heavy-duty for overseas. All Leyland overseas branch managers were recalled to discuss the new designs, and whilst expressing approval, they pressed for a mediumcapacity type. The reasons being certain limitations on axle weights and a distin,t line of demarcation between the stout vehicles of 12 tons gross and lightei types largely based upon car practice, a gap more marked overseas than here. Thirdly, there is a demand fc,r a reliable oil engine on a vehicle which would meet this need. To cover these points the Comet was designed.
Before the recent war, the Lynx was available with either petrol or oil engine, and, suitably modified, it had won much succes:. abroad, but it A28. was felt that a mlre robust model was wanted—the Lynx, with everything a little bigger. Thus the Comet has an oil engine of 75 b.h.p. at 2,000 r.p.m., a large, single dry plate clutch, five speeds instead of four, and a hypoid axle to give pinion strength with worm silence, space being afforded to provide a second ratio at choice.
The reliability of Leyland oil engines led to the scaling down of the famous 600 type, and the result is a directinjection, six-cylindered unit with a compression ratio of 16 to 1, a bore of 3.8 ins. (96.5 mm.) and a stroke of 4.5 ins. (114.3 mm.), giving a capacity of 306 cubic ins. (5 litres), a maximum torque of 220 lb./ft. (30.4 k.g.m.) at 1,100 r.p.m., and a minimum fuel consumption under full load of 0.385 pt. (185 grms.) per b.h.p./hour. Cylinder block and crankcase are an integral iron casting with dry-type, sliding-fit liners and cast-iron head. Stellited valve seats are frozen in. Polishing of the alloy-steel connecting rods assists crack detection. The bigends have indium-coated, copper-lead. steel-backed thin-shell bearings, and the nitrided alloy-steel crankshaft has seven of this type. It carries a torsional vibration damper, externally, at the front. The aluminium-alloy pistons, with toroidal combustion chambers, have five rings.
Valves are of silicon-chromium steel, faced with Stellite, The stems being chromium flashed. They are operated by push rods and rockers, and a decompressor acts on those for the exhaust. Helical-toothed gears attend to the timing, the camshaft and auxiliaries being driven from the front end. A gear-type pump supplies oil mainly through drilled passages, and a springloaded relief valve is accessible from the left-hand rear. The oil capacity is 3,4 gallons (16 litres). A C.A.V. fuel pump operates with Leyland multi-hole injectors, which are clamped at one point to avoid distortion. A vacuum governor keeps the idling speed at about 350 r.p.m., and the maximum to 2,000.
The oil fuel passes through a large filter before it reaches the engine, and then through a Leyland edgewise filter
located in the inlet adapter of each injector, fuel leak-off returning to the main tank. The inlet manifold has an effective air cleaner. Water circulation is by centrifugal pump with self-adjusting carbon gland, the water being directed on to the injector and exhaustvalve housings. A thermostat bypasses the radiator until the water outlet temperature reaches 185 degrees F.
The radiator has 31 Still tubes, each removable. The unit is carried in rubber bushes on the engine front bearer.
To assist cooling, the clutch facings are slotted radially; radial holes are drilled in the flywheel and the cover has louvres_ Adjustment for clutch wear is effected by -reversing three pressure pads engaging with the withdrawal levers.
The bell housing is bolted to the crankcase, and to it is secured the gearbox, which gives five forward ratios and a reverse, all the pinions having helical teeth. First and second gears slide on helical splines, whilst the others are in constant mesh. An additional gear can be fitted to drive a power take-off. This is standard on tipping models. The gear ratios are: direct, 1.55, 2.49, 4.21, 7.12 and reverse 7.45 to 1. The drive is by a two-piece propeller shaft with Hardy Spicer needle-roller joints, except for the tipping model, which has a single shaft.
Unusual strength is found in the back axle, with its hypoid gearing and provision for a second ratio if required. The main casing is of cast steel with forged-steel tubes spigoted to it and secured by large flanges and studs.
The differential has four bevel pinions, and . the wheel hubs are mounted on taper-roller bearings. •
Brake facings are protected from oil leakage by large collectors. The axle ratio is 6.1 to .1, with alternative ratios of 5 3-7 to 1 and 61. 1... _Suspension is by semi-elliptics, 3 ins. (76 mm.) wide, the leaves being shot., peened on the tension side and edges.
The brakes are Girling-Bendix with two leading shoes, operated by Lockheed hydraulic and Clayton Dewandre servo. Each front brake has an hydraulic cylinder, but the rear brakes have only one cylinder—on the axle, with pull rods to the wheels. Mechanical linkage is provided for the hand brake.
Steering is by Mantes cam and double-roller gear and spring-spoked wheel.
The electrical system is C.A.V. 24-volt with axial starter. For the tipping model a three-way Bromilow and Edwards gear and 5 cubic-yard body (3.823 cubic m.) can be supplied.
The following • particulars of the freight, dump and tractor models, which can have right or left-hand drive, are given in that order; gross rating export, 20,700 lb. (9,389 kg.), 20,700 lb., 34,700 lb. (15,740 kg.); chassis and cab, 6,720 lb. (3,048 kg.), 6,620 lb (3,093 kg.), 6,520 lb. (2,958 kg.); wheelbase, 170 ins. (4,318 mm.), 125 ins. (3,175 mm.), 110 ins. (2,794 mm.); frame length behind cab, 176 ins. (4,470 mm.), 119 ins. (3,023 mm), 104 ins. (2,642 mm.); turning circle, 60 ft. (18.288 m.), 45 ft. (13.716-m.), 40 ft. (12.192 m.); tyro size, 9.00 by 20. Weights apply only
to oil-engined chassis. With petrol engine and 12-volt equipment, each will be reduced by 168 lb.
The passenger chassis is designed for single-deck bodies seating 32-35. Its wheelbase is 210 ins. (5,334 mm.). In this case the engine-gearbox unit is mounted by the Leyland link system, and the axle ratio is 5 3-7 to I, with an alternative of 6i• to 1. Tyre sizes can be 8.25 by 20 or 9.00 by 20.