The Fast 20-Seater; What Guys are Doing

An article from 'The Commercial Motor', 30th October 1928. Courtesy of Brendan Kinsella.

The New OND Model Guy is a Robust Product at a Moderate Price

Much attention has been given during recent years to the development of the large capacity coach and bus capable of travelling at much higher average speeds than were formerly possible, and it seems that the smaller passenger vehicles have been somewhat neglected. For this reason the latest product from the Wolverhampton works of Guy Motors, Limited, should, receive a warm welcome from those users and potential users of vehicles of moderate capacity.

Even a cursory inspection of the new OND model Guy chassis will reveal the fact that it is no ordinary semi - converted goods model, but one designed expressly for the purpose which it is called upon to serve, including as it does, an extremely powerful and live engine, a frame dropped at the dash and arched over the rear axle, Dewandre-operated front-wheel brakes, and a most complete equipment.

A 20-seater bus in which the new Guy chassis is used.

Road tests, with this model, fully laden; have revealed a surprising turn of speed. The vehicle speed at 1,000 rpm. of the engine is 18.8 mph. and the engine is easily capable of 8,000 rpm.; actually 49 mph. has been obtained with ease. Gear changing is finger-light, the steering easy and affording an excellent lock; furthermore, long, fairly stiff gradients can be climbed on top gear and on the lower speeds little more than a faint hum can be heard.

The following are the main dimensions, etc.: Engine four cylinders, 90 mm. bore and 130 mm. stroke, rated at 20 hp.; gear ratios, top, direct, third, 1.7 to 1, second, 2.61 to 1, first, 5.27 to 1, reverse 8.23 to 1; axle ratio, 5.4 to 1; wheelbase, 12 ft. 3 ins: track, 4 ft. 9½ ins.; overall length, 18 ft. 10 ins.; dash to end of frame, 14 ft. 8 ins:; frame height under load 2 ft.; ground clearance under front axle, 12½ ins. under rear axle, 7¾ ins.; turning circle, approximately 50 ft.; chassis weight approximately 35 cwt.

The frame is built up with side members 6 ins. deep with 2¼ ins. flanges, the material being ¼ ins. thick. There is a deep, dropped cross-member at the front to carry the forward pinion support of the engine-gearbox unit, and both tubular and channel-section cross members elsewhere, two being bolted right through to the pressed-steel rear spring brackets. The suspension is by long semi-elliptic springs with bushed eyes. Tecalemit-Zerk lubricating nipples are utilized throughout the chassis.

The forward end of the engine in the new Guy, showing one of the rocker-operated valves, and the camshaft oil lead containing the relief valve.

In the power unit the four cylinders are cast en bloc with the upper half of the crankcase and the head carries the valves and rocker gear, which is operated by push-rods from the camshaft in the crankcase.

The rockers carry ball-ended adjustable pins working in oil cushioned cups on the push rods.

Cast iron pistons, each with three ordinary and one scraper ring, are utilised.

The gudgeon pins are dowelled into the pistons and held by wide spring steel bands. White metal-lined shells are fitted into duralumin connecting rods.

There are three main bearings for the extremely robust crankshaft. Quietness is assisted by the use of helical timing gears and a skew-gear for the cross-shaft, which drives a Lucas magneto at the near side and a centrifugal-type water pump at the other. There is a breather on the timing case and the dynamo can be flange-fitted at either side.

Circulation of the engine oil is effected by a submerged pinion-type pump driven from the camshaft. The oil enters a readily accessible external filler chamber from which one lead takes it to the main bearings and thence through the drilled crankshaft to the big ends, whilst a second lead takes it to a relief valve chamber bolted to the cylinder head, and from this to the hollow shaft carrying the rocker arms. Distribution of the mixture from the triple-diffuser Zenith carburettor is effected within the cylinders, but the exhaust manifold is external. A hot-spot is embodied in the arrangement.

The cooling water is circulated around a gilled-tube, cast-aluminium radiator of pleasing design through which air is drawn by a large cast-aluminium fan mounted on ball-bell rings on an eccentric spindle and driven by an endless rubberised-fabric belt. The bhp. developed is 23 at 1,000 rpm., 34 at 1,500 rpm., and 38 at 2,000 rpm.

Twelve compression springs are utilised for the single-plate clutch of the semi-steel flywheel, which is totally enclosed in the engine-gearbox unit but can be examined through an inspection hole provided with a steel cover.

Engine accessibility as exemplified in the Guy. Note air cleaner.

Four forward speeds are given by the gearbox, which has short, stiff shafts and wide-toothed pinions carried in a one-piece casting, in the cover of which is mounted the selector mechanism. A particularly interesting feature is that either central change or right-hand gear control can be provided. In the latter case, the lever is mounted on a cast aluminium extension of the gearbox cover. At the off-side of the gearbox is a plate which can be detached to permit a power take-off from the layshaft, whilst at the rear of the box on the third motion shaft is the positive gear drive for the speedometer.

A semi-plan view of the new OND Guy passenger chassis.

Behind the gearbox is a two-piece tubular propeller shaft with three ply Hardy flexible fabric joints at the forward end and a Spicer all-metal joint with a plunger at the rear end, a centre bearing being provided.

A horizontal banjo forged casing of exceptional strength is used for the rear axle, which is driven by an underneath worm. All the wheels are carried on taper-roller bearings.

The front axle is of the reversed Elliott pattern with the truck rod at the front. This rod has ball and socket joints, whilst the drag-link is provided with spring loaded ball joints.

Duplex brake shoes are provided for the rear wheel drums, one set of shoes being controlled by the hand lever, whilst the other set is coupled up with the front brakes and operated through the Dewandre servo. Spherical bushes on the two cross-shafts prevent any risk of binding through frame flexion. The brake drums are deep-flanged forgings with, dust covers for the shoes and the hand brake is not compensated, so simplifying the gear.

Brake adjustments are made by turnbuckles and sprung snap-over wing-nuts at the extreme ends. At the near side of the frame is mounted a 16-gallon petrol tank from which the carburettor is supplied by an Autovac.

It is obvious that close attention has been given to that vitally important point, accessibility. Inspection covers are provided for the timing gear, Bendix pinion of the starter, big-ends, etc., whilst the three-point mounted engine-gearbox unit can easily be removed from the front.

Although the chassis we illustrate is arranged for the normal driving position the company is quite prepared to provide a chassis with forward control, and to facilitate this, the engine is so designed that all its auxiliaries are accessible from the near side, although the dynamo can be mounted at the other side if desired.

The tyres provided as standard are 30 inch by 5 inch twins at the rear, all on steel-disc wheels, a spare wheel and tyre being included. As an alternative, 33 inch by 5 inch tyres can be provided at an extra cost.

The rear spring brackets are light but strong.

The chassis is designed to carry a net load of 27 cwt., and the gross load, inclusive of body, must not exceed 2 tons 5 cwt. With 12 volt, five lamp lighting set, starter, speedometer, air cleaner, electric horn and Dewandre servo, the chassis price is £445.

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