Much Improved
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LEYLAND PASSENGER MODELS
New Tiger and Titan Six-cylinder Petrol-engined Chassis for Singledeck and Double-deck Vehicles. Larger Body Space and Superior Performance
AT the works of Leyland Motors, Ltd., Leyland, Lanes, a few days ago we were permitted to examine the latest Tiger and Titan six-cylinder petrol-engined chassis for passenger bodies. The chassis are practically identical,_ but the Titan is different as regards frame end, etc., to enable it to carry double-saloon bus bodies.
In brief, it appears to us that ail the good features of the former models have been retained, whilst a number of important improvements has been incorporated, based upon long and extensive experience of vehicles in public service. Although the wheelbase remains at 17 ft 6 ins., the body space has been increased from 22 ft. 6i ins. to 23 ft. 1 in.
The engine has been altered so as to give better performance, and the improvement is utilized so that the same power as previously is developed with a lower petrol consumption, whils.t a particularly good torque reading is obtained at low crankshaft speeds. These results are due mainly to alterations in the induction system ; the manifolds are increased in size and there B26
are now six separate branches for the exhaust pipe. The manifolds are easily
fitted, being located on long dowels and held on by clips.
T h e cylinder head is altered in that all the ports are increased to 11 ins, diameter, the valve seats being cut at an angle of 30 degrees, so as to give increased power and better cooling. Stellite-faced steel exhaust-valveseats are used, and are screwed into place. The gasket and cylinder-head cover joint have been improved.
The camshaft now has four, instead of three, bearings, thus relieving the head of stresses, and the camshaft-drive gear can now be adjusted after assembly of the head, by means of friction-drive discs, which are bolted together. The carburetter, of course, has been increased in size. The cooling capacity of the radiator has been increased about 50 per cent., and the unit is now mounted on substantial rubber blocks directly on the frame. It is of a new shape and has a grille front to give improved appearance and a better air flow. Thermostatic cooling control is available as an extra.
The fan is of Elektron and has a simple friction drive, with no dogs to rattle. The engine staler is mounted on the off side, accessible from below, and the ring gear is now bolted to the flywheel to permit resetting after local wear. _ As regards engine auxiliaries, a new type of water pump (the non-adjustable kind with carbon gland and nitrided steel shaft) . is fitted. The standard dynamo is a 7-in. unit of 12 volts or 24 volts, but the mounting will accommodate an S-in. unit.
Theoil filler on the engine is now easier of access and the strainer prevents accidents, such as the dropping of small parts into the crankcase; the breather is built into the crankcase. Another point in connection with the oiling system is that the oil-relief valve is easy to adjust or to remove for cleaning.
A Tecalemit pad-type filter is fitted which is easily removed for cleaning, and there is a by-pass valve to operate in case of neglect. A gauze suction filter also is provided in the sump, and the ingress .of carbon particles is prevented. This filter, again, is easily removed through a cover -in the base. All oil is filtered and cooled before reaching the bearings.
The Simms automatic-advance device for the magneto of the same make is now built into the front arm of the crankcase, in which position it is carefully protected in the matter of lubrication, etc. The engine crankcase is now of Elektron and, for this reason, has had to be specially designed, incorporating a horizontal flange below the dynamo level, which greatly improves the stiffness.
The flymheel housing is now larger, because the size of the clutch has been increased, and the rear engine cross-member is well insulated from the frame by the use of rubber. The clutch has . been quite considerably improved, especially as regards ventilation, and is designed to withstand 75,000 miles of running with six halts per mile. The surface area has been increased to 288 sq. ins.
There is now a renewable clutch hub, also a better withdrawal gear, so that the throw-out race is stationary when the clutch is engaged. The renewable hub is tapered and keyed and has an outer diameter of 4i ins., and the siilines are 12 in number. A "silentthird " gearbox is now adopted, with . helical constant-mesh gears, and the box is made of Elektron.
. The brake gear has been improved, a single pair of shoes 6 ins, wide being employed in each rear drum, and being operated by either foot or hand control, incorporatinga lost-motion link. The shoe facing material is in. thick and improved cams are adopted, so that this thickness may be used up without the need for packing pieces. By means of serrated camshafts, the cam levers can be reset after the facings are half worn. The master Dewandre brake cylinder is now mounted inside the frame, permitting the battery box to. be fitted obtside, and effective brake adjustment is possible from the cab.
The rear axle has been redesigned to give 7i-in., instead of 7-in, worm centres. The casing itself is lighter than previously and has an inspection cover, the wheels being carried on Timken bearings. The worm casing, which is of increased oil capacity, is of Elektron, and the oil seals are improved. The axle shafts now have round splines.
'rho springing has been improved and Luvax hydraulic recoil dampers are fitted all round. A commendable petrol-tank installation is now em
ployed, substantial brackets built into the tank being picked up by mounting screws which pass through the off-side frame member. It is extremely easy to lower the tank from the vehicle.
The frame itself, by the way, has been lightened, as well as stiffened, and an improved method is used of attaching the spring shackles and crossmembers. The driver's seat is now adjustable, and the headlamps, with chromium rims, are interchangeable.
The front axle is of a new section to give better resistance to brake reaction, and the front brake cylinders are mounted on the swivels, with an acces
sible adjustment. The steering is improved, the stub axles being more compact and having a better king-pin angle. The drag link now works fare and aft, instead of transversely, and there are self-adjusting ball ends.
The improvements adopted do not result in increased weight ; on the contrary, due to the use of Elektron and to improved design, the weight of the chassis complete has been lowered from 4 tons to about 3 tons 19 cwt. The company's tests of the new chassis, laden to Si tons, have yielded, on an average road, fuel consumption at the rate of about 9.23 miles per gallon.