1930 PLANS
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of an American Corporation with World wide Interests
Four G.M.C. Models for Loads from 35 cwt. to Four Tons and Two Chevrolet Six-cylinder Chassis will be Available Henceforth,
-CIROlf the British headquarters of .12 General Motors, Ltd., at Hendon, London, N.W.9, we learn that the 1930 range of G.M.C. commercial chassis comprises four six-cylinder models, the smallest being suitable for an 18seater passenger body or a useful load of 35 cwt. of goods, and the largest being intended for service as a 30seater passenger coach or bus or a 4ton goods vehicle. In addition, the company is marketing. the 12-cwt. and 30. cwt. Chevrolet chassis, the latter being suitable for service as a 14-seater passenger vehicle.
The smallest of the G.M.C. range, namely, the T19B model, has a sidevalve engine of 341 ins. bore and 3/ ins, stroke, which develops its maximum of 58 b.h.p. at 3,000 r.p.m. The two intermediate models, i.e., the T30 and the T42, both have the Buick standard engine, which also has a bore of 3/5-6 ins. but a longer stroke of 4a ins. This engine is of the overhead-valve type and develops 72 b.h.p. at 2,500 r.p.m.
The biggest, or TOO chassis, is equipped with the Buick Master overhead-valve engine, the bore of which is 3a ins, and the stroke 5 ins. This power unit develops no less than 89 b.h.p. at the moderate speed of 2,500 r.p.m. Both the Chevrolet models have the well-known Chevrolet sixcylindered overhead-valve engine, with 3-& ins, bore and St ins, stroke, the smaller chassis differing from the larger in that it has a three-speed gearbox instead of a four-speed gearbox, a shorter wheelbase, a lighter frame and suspension and smaller tyres.
Turning to the senior range, innovations for the forthcoming year are noticeable in all models. The T19B chassis now has twin rear-wheel equipment and, taking the place of the T20 model 30-cwt. chassis, it easily carries a 35-cwt. load. The petrol tank is now mounted under the driver's seat, the petrol feed being by an A.C. diaphragm-type fuel pump, which is driven by an eccentric on the camshaft. This affords a positive supply varying with the speed of the engine, and a by-pass arrangement prevents overcharging of the carburetter. The pump has.-a visible-type fuel filter.
The crankcase of this engine is a single casting in iron, the head being detachable in two parts. The crankshaft has three bearings, the front being 14 in. and the rear 21-16 ins, in diameter. Pressure lubrication to main and connecting-rod bearings is effected by a geared pump. A centrifugal pump is interposed in the water system. .
The Delco Remy six-volt batteryignition, lighting, generator and starting set is standardized. The singleplate, dry clutch and four-speed gearbox are mounted as a unit with the engine, the whole being three-point suspended in the frame. The 'rear axle has a spiral-bevel,drive, the .axle shafts being of the semi-floating pattern.
Rendix three-shoe; self-energizing brakes are fitted on all wheels. The wheelbase of this model is 12 ft. 1i in., and the overall length 17 ft. 411 ins.
The latest type Buick standard engine, as fitted to the T30 and T42 models, has a fuel pump of the kind described above and incorporates, as a new feature, forced ventilation of the crankcase. This engine has an exhaustjacketed induction pipe, the temperature of which is controllable from the dashboard. Another good feature is that the oil filter is mounted externally and is easily detachable. The T:() model has a slightly longer wheelbase than previously, the length now being 13 ft. 8 ins., whilst the overall length is 20 ft. 8i ins. The T42 model, which is suitable for three-ton loads and can be employed as a 24seater bus or a 20-seater long-distance coach, also has in its latest form a longer, frame, the wheelbase now being 14 ft. 7 ins, and the overall length just under 22 ft. ,
The T60, or Developer model G.M.C. chassis, is an entirely new four-tonner, so far as this country is concerned. It is the only one of the range which has an overhead-worm-driven rear axle, the torque of which is borne by two stout radius rods spring-bracketed on the main frame member. The standard gear ratios on this machine are respectively 44.8, 27.6, 12.9 and 7.3 to 1, the reverse ratio being 47.2 to 1.
The transmission line comprises two tubular propeller shafts with three universal joints. In order adequately to cope with a, 4-ton load silico-manganese steel is used in the manufacture of the semi-elliptic springs. The leaves are 3 ins, wide, the front springs being 3 ft. 4 ins, and the rear springs 4 ft. 6 ins. long. On this model, also, Bendix three-shoe internal brakes are fitted on all wheels, these being operated by the pedal, whilst a transmission brake is actuated by the hand lever. Standard tyre equipment is 34-in. by 7-in, pneumatics with twin tyres on the rear wheels.
To give some idea of the prices of the various models, the T30 chassis, equipped with a 20-seater bus body, costs £870. The T60 model costs £825, the T42 £625, the T30 £545, and the T19B £375 in chasst form. It should be noted that Jill the G.M.C. models have straight pressed-steel frames, Chevrolet chassis have up-swept frames.