AN ENTIRELY NI LIGHT TONNER.
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The New Morris which is Designed Primar Within the &lb Tax Category. A Soun Sell at a Competitive Price, and to Fall mstructed but Light Modern Chassis.
TN designing and produeing a new Light Tonner _I–chassisMorris Commercial Cars, Ltd., of Soho, Birmingham, has had in front of it certain definite ideals. The designer has obviously realized that there is a growing market for a vehicle light in weight—and consequently in running expenses—cheap in first cost, yet capable of carrying a substantial load at a good speed. Probably the most important factor of all, however, is that the vehicle should fall within the category of those taxable at no per annum-.
These ideals and others correlated thereto have unquestionably been attained, and modern quantity production combined with an economic layout for the whoie of the chassis have gone hand in hand to produce a serviceable, cheap and reliable vehicle.
Few concerns connected with the motor industry can boast the extensive works and business premises occupied by Morris Motors, Ltd., and the companies originating from the parent firm at Oxford. Thus the facilities available for manufacturing economically are almost unique in this country and we may look to this new vehicle to cope quite successfully with the oft-threatened foreign invasion of the market for cheap commercial vehicles.
Before describing the chassis in detail it should prove illuminating to review some of the main dimensions of the vehicle, together with certain of the weights, loading capacities, etc. With pneumatic tyres, wings, footsteps and complete equipment the chassis weight comes out at 151 cwt. With a van body, and the vehicle ready for the road the net unladen weight is 19i cwt. The open truck weighs 191 cwt., so that it will be seen that both the van and the truck come well within the weight limit for the class taxed at £16.
The height to the top of tile chassis frame (loaded) is 2 ft. 3 ins., which, with a wheel clearance of 6 ins. (to the top of the wheel arches), allows a reasonably low platform height when the body is fitted. With 32-.in. by 41-in. tyres there is a minimum ground clearance of 10 ins. Actually, beneath the front axle there is a clearance of 13 ins., whilst under the overheadworm-driven axle there is 10 ins. clearance.
The useful load is evenly distributed over the rear axle—as a glance at the illustrations will show— which should result in general stability and comfortable riding under severe driving and braking loads. The overall length of the complete vehicle is 14 ft. 6 ins. and the width 5 ft. 81 ins., whilst the height to the top of the cab is 7 ft. 2 ins.
The power unit is similar to the types already supplied by this company. The engine, clutch and gearbox are all formed as a unit and mounted in the frame at four points. Each of the four cylinders has a bore c32
of 75 mm., and the piston stroke is 102 mm., giving a total cubic capacity of 1,802 c.c. Although the, engine is of comparatively small dimensions, the actual power output is very satisfactory, 11.5
b.h.p. being available at 1,000 r.p.m.,
17.9 b.h.p. at 1,500 23.5 b.h.p. at 2,000 r.p.m. and 27.25 b.h.p at 2,500 r.p.m. When mounted in a light chassis, such as this new tonner model, the road performance should,' therefore, be highly satisfactory.
The cylinders are cast en bloc, with the inlet and exhaust valves ranged along the near side. The upper half of the crankcase is formed as a unit with this casting, which also contains the three main bearings for the crankshaft, thus ensuring a general rigidity and correctness of alignment for all reciprocating and revolving parts. The cylinder head is detachable to facilitate decarbonization, and the corn bustion chambers are of such a shape that good turbulence and, consequently, quick burning of the mixture are obtained, two features which combine to give a high power output and satisfactory mileages between decarbonization periods.
Duralumin connecting rods and aluminium pistons are provided and these nable the engine to be run at high speeds without andue vibration or excessive
loading of the bearing surfaces. All the valve tappets are adjustable and, together with the valve stems and springs, are enclosed by a detachable oil-tight cover plate. This cover plate, however, can be removed quite easily when tappet adjustments are necessary.
Lubrication is by submerged plunger pump driven from an additional cam on the camshaft, which forces oil under pressure to all the -main bearings and to the timing gear. The big-ends of the connecting-rods, however, obtain their supply of lubricant from troughs— formed in a tray located above the oil in the sump—which are constantly filled during the time the
engine is running. To keep the system clean an easily detachable gauze filter, Which surrounds the pump intake, is fitted, whilst as a guide that all is well with the lubrication system a gauge is fitted on the dashboard.
There is a device incorporated in the system whereby the supply of lubricant is automatically increased alien the vehicle is ascending a hill and decreased when less power is required on down grades. A point worth mentioning with regard to the connecting-rod big-end bearings is that shims are fitted so that when wear takes place it can very easily be taken ttp. The distribution gear for the camshaft and magneto consists of spiral-spur; pinions, the camshaft obtaining its drive from the end of the crankshaft by two gears lying in one plane, whilst the axis for the magneto gearwheel runs at right angles to the camshaft gear and immediately above it. By this layout the contact breaker and distributor face outwards from the engine and are thus in a convenient position to permit inspection and adjustment, or for cleaning purposes.
So far as the exterior of the engine is concerned, an extremely clean outline has been obtained, which gives the impression of simplicity and, as has already been outlined, convenience in maintenance work has received its share of attention.
Mixture is supplied to the cylinders by means of a Smith single-jet carburetter bolted direct to the off side of the cylinder block, a passage being east between cylinders Nos. 2 and 8 for distribution of the mixture to the valve ports. The exhaust gases are carried away by a simple manifold bolted directly to the exhaust ports on the valve side of the engine, thence to a silencer located in the normal way approximately in the middle of the chassis.
In order to encourage the user to maintain the correct tyre pressure a mechanically operated pump is included in the standard equipment. The pump itself is a Max-field type, is driven off the camshaft and can instantly be put into, or out of, engagement while the engine is running, if desired. Sufficient flexible tubing is supplied to enable all tyres to be inflated while they are actually on the wheels.
A lighting set is, of course, part of the standard equipment, the dynamo being driven by a chain from the rear of the crankshaft.
Bolted to the rear of the flywheel casing is a bell housing for the clutch and gearbox, an arrangement which ensures a completely rigid structure and avoids any possibility of the mis-alignment of the driving shafts.
The clutch itself is a multipIe-plate cork-insert type running in oil and the three-speed gearbox is operated by a centrally disposed 'lever. The gears themselves are of nickel-chrome steel and are mounted on short, stiff, splined shafts which run on ball bearings. Choke of three gear ratios is offered-7.33 to 1, 6.25 to 1 and 5.5 to 1, so that users living in parts of the country having different configurations can be suited exactly to their requirements. With the lowest of these ratios the second gear is 12.6 to 1 and the first gear 23.4 to 1, the medium set of ratios give 10.75 to 1 for second gear and 20 to 1 for first, whilst the highest of the three sets gives 9.46 to 1 and 17.6 to 1 for second and first gears respectively. In each case the reverse ratio is considerably lower than the bottom forward gear...: The power is transmitted to the overhead worm driven rear axle by means of a tubular propeller shaft of . exceptionally large diameter. This shaft is equipped with a fabric-disc joint at the forward end, c34 a ball spigot being provided for centring purposes. Springing is by semi-elliptics all round, and the rear springs are equipped with Stott anti-bounce clips, which in effect use the spring plates as a means for damping out excessive spring movement.
The rear axle has a sturdy appearance and is mounted beneath the springs by means of two pairs of IT-bolts, which pass right around the axle casing. A two-wheel braking system is incorporated. There is no compensation whatever in either hand or foot-operated controls, but both apply rods which in turn rotate cross-shafts located as near as possible to the anchorage for the forward end of the rear springs. On the extremities of these cross-shafts swinging levers are fixed whence further rods are coupled to arms on the cams within the -brake drums. The two primary control rods, i.e., the rods running from the pedal and hand lever to the cross-shafts, have turnbuckles located in a convenient position for adjustment purposes, whilst each rod is also adjustable by means of a screwed fork joint.
Steering is by worm and complete wheel, the shaft for the worm wheel being capable of receiving the drop arm in a variety of positions. so that when one section of the worm wheel becomes worn it can be turned round into a new position.
The dash is a most Interesting arrangement. It is built, up from a series of pressings which have been scientifically produced in order to give a rigid attachment for the petrol tank, facia board and body sides. The result ls that, although cheap to manufacture in. quantities and light in weight, the strength has not been impaired.
The petrol tank holds 8 gallons of fuel and is 'equipped with a two-'aY tap giving a reserve supply
of fuel, thus obviating the necessity for carrying a spare can. The normal equipment includes a six-volt lighting set with three lamps, but a starter can be provided, if desired, at an extra cast of £10. The price of the chassis with five artillery wheels, 32-in. by 4i-in. straight-sided Dunlop tyres, running boards, front wings, valances, etc., and engine-driven tyre pump is £175.
At the present time two bodies are available, one a truck and the other a van. The floor area of the truck is 371sq. ft. (length 7 ft., breadth 5 ft. 3 ins.)., and the body sides hinge down. The price complete is £205.
The van is of quite an attractive shape and is very roomy. Actually the space available for the useful load is 120 cu: ft., the length from behind the drivees seat to the rear doors being slightly more than 6 ft., the width 4 ft. 6 ins.; and the height 4 -ft. 4 ins. There are two doors at the .rear of the body, eaeh one• equipped with an ()Val glass panel to facilitate manceuvring in reverse. As will be seen from the accompanying 'photographs there is plenty of room underneath the body to effect minor repairs to brake work and greasing up of the chassis generally—a feature that should be appreciated by the busy user., A seat is provided running right across the body on which four passengers can be accommodated at a pinch, the driving seat having a cushion and backrest, whilst the remainder of the seat is left open. There is a capacious locker for tools, spares, or personal
appurtenances contained in the framework of the seat. The roominess of the cab has not been impaired despite the comparatively short wheelbase, and the near-side door is sufficiently wide to allow quite a big driver easy ingress and egress. The price of this vehicle complete is £215.