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Promise Fulfilled

12th March 1965, Page 64
12th March 1965
Page 64
Page 65
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Page 64, 12th March 1965 — Promise Fulfilled
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ROAD TEST: Austin FJ 5-tonner By A J P Wilding WITH the major emphasis at last year's Commercial Motor Show on new maximum-capacity vehicles, the British Motor Corporation was almost alone in providing interest in the medium-weight classes. This it did with the Austin and Morris FJ models which, although using existing engines, were in every other respect completely new designs. There are four basic models in the range; as well as the 5-tanner tested there are 7and 8-ton rigids and an 18-ton g.t.w. tractive unit. All were described fully in The Commercial Motor of September 25, 1964, and although • it may seem a long time between the introduction of the range and completion of a road test, this was because no example has been made available until now. This also applies to other makes new at the Show.

As it has turned out, this _test of the FJ is the first of one of the many new models introduced at Earls Court that were not based on previous designs. Most people who saw the El at the Show, or read reports about it, will have agreed that the design has many commendable features. It is not just a re-bash of the FH modes that it replaces, as, apart from the well-designed and luxurious tilt cab, the FJ has a well-designed and up-todate braking system, a fivespeed ENV synchromesh gearbox and other good points. The initial promise that the range seemed to have when it was introduced I found to be fully justified on this road test. I have driven few better vehicles; the cab is really excellent, and I found the performance, general handling and braking very good, whilst the fuel consumption is adequate.

Except for a BMC two-speed rear axle the 5-tonner tested was perfectly standard. This model has the 5.1-litre BMC diesel engine-which produces a maximum net output of 90 b.h.p. at 2,400 r.p.m. and a maximum net torque of 224 lb. ft at 1,500 r.p.m. In the other Fl models there is a 5.7-litre engine producing 105 b.h.p. and 255 lb. ft. torque. The engine is mounted in the chassis at an angle of 61° to the vertical (over to the left-hand side) and the drive is taken through a 13-in.-diameter clutch with air-overhydraulic actuation to the gearbox. As well as the box fitted in the test vehicle, which had direct top, an overdrivetop unit is available as an option.

• There are three alternative ratios for the standard singledrive rear axle-5.86, 5.125 and 6.67 to 1—and, whilst the 5.85/8.13-to-1 two-speed unit in the test vehicle is standard, a 5.125/7.13-to-1 driving head can be specified. The ratio change is air operated and this was found to work well on the chassis tested. On the other models in the FJ range the same gearboxes as on the 5-tonner are standard and optional, and except for the 18-ton tractive unit a single speed axle is standard with a two-speed optional. The latter is the only fitting on the 18-ton-gross machine.

As already mentioned the braking system is an important and praiseworthy feature of the FJ design. On all models the brakes are hydraulically operated with air assistance. The hydraulic lines to the front and rear brakes are on separate circuits, these being fed by a tandem master cylinder. This means that in the event of a single failure in the hydraulics, there will still be brakes at one axle. The air assistance to the hydraulic operation is provided by a dual air-pressure servo (or actuator) which carries the master cylinder. Air is fed to each section of the servo by separate lines from a dual-concentric brake valve fed by a twin-tank air reservoir.

In the event of a failure in one of the air lines, the system is designed to provide just under half the normal service brake efficiency. A dual-air-pressure gauge is included in the instruments in the cab and there are also dual-low-pressure switches to each of the air-pressure circuits. These actuate a buzzer so that in the event of an air failure the driver will be warned. Another device incorporated in the dual actuator is .a " telt-tale " piston which operates a buzzer when it is moved a certain distance by the actuator piston. This shows the need for brake adjustments because of excessive movement at the shoes. The handbrake is mechanically applied, but to improve the efficiency of this item air-pressure assistance is provided in the form of a diaphragm-type chamber acting on a relay lever in the line. Pressure to the chamber is supplied by a valve coupled to the linkage which allows air from one of the brake reservoirs to the brake chamber.

The braking system is designed to cater for the most stringent requirements existing on the Continent, and in some ways is better than some of the brake layouts designed for vehicles to meet the new requirements for an adequate secondary braking system. In general these secondary, or emergency, systems give power braking on one axle (in the case of four-wheelers) to obtain the required 25 per cent. But in my opinion a system which gives partial braking at all wheels is to be preferred, because if the same effort is applied to the brakes of only one axle there is a good chance of the wheels locking when the road conditions are not good, which can be most detrimental. A point on which BMC deserves praise is that it is the only company offering on a voluntary basis a brake system with adequate safety features to cater for failure—so far only

vehicles designed to meet the new regulations, and therefore having to have a secondary system, incorporate one.

The cab on the FI gives the driver as much luxury as he would get in a passenger car. Adequate room is provided for two passengers as well as the driver, and as the engine is located beneath the seat-support pressing, there is free access across the cab—only the gear lever is in the way. Both the single driver's seat and the double passenger seat are very comfortable, although the test vehicle did not 'have such soft padding or luxurious upholstery as the Show models had. Visibility is very good, as also is the standard heating system—there is a 5-kV heater and demister unit. Ventilation should also be no problem as there are swivelling quarter lights in both doors, full-drop side windows and a central window in the back of the cab which can be lowered also. Ventilation was not tried out on the day of the test—with temperatures around freezing point and a biting east wind—but the heater certainly proved to be well up to the job.

The standard of fitting and finish inside the cab is very high and a good deal of thought has been paid to making the driver's life easy. Controls for direction indicators, horn and lights are on the steering column. A very good B28 idea is using toggle-type switches for other electrical components and mounting them in a panel above the windscreen in front of the driver. There are four of these switches—for wipers, panel light, heater blower and engineoil-level checking. The heater blower must be used to get the full benefit of the heating system, as without it there is little or no air current through the heater when the vehicle is going forward. The oil-level gauge for the engine is on the dash and operating the switch brings this into action. Other instruments provided are a temperature gauge, a fuel gauge and an ammeter, as well as a speedometer, of course.

Access to the cab is very easy because of the forwardentry steps ahead of the front wheels, and even with the largest tyres on the heaviest FT the first step is only 2 ft. From the step to the floor of the cab is a further 1 ft. 3 in., and there are grab handles fitted on the front pillars. In both doors there are stowage pockets for papers and so on, and there are also cabby holes on either side of the instrument panel. Part of the test was carried out in darkness and the four-headlamp system was found to be very good. Worth mentioning is the fact that a relay is included in the flashing direction indicator and stop-lamp circuits

by which the light output of these lamps is reduced when the sidelamps are on.

Cab insulation against noise was found to be effective, as itwas relatively quiet inside even at maximum speed, and possible to carry on a normal conversation. Only on one point could 1 find fault with the facilities provided— there is no ashtray on the passenger side, the only one being between the steering column and the driver's door. This is a very small point and easily remedied by buying another ashtray for a few shillings if this is required.

The tilting mechanism for the cab consists of a torsion bar located at the front end of the chassis frame and attached to stout brackets boiled to box-section longitudinal members integral with the cab. The cab is held down by bolts through the rear rubber/steel support bushes into • brackets on the chassis side-members. No attempt was made to tilt the cab of the test vehicle, as conditions were against it, and in any case I had already seen this done at the Austin works. A certain amount of dismantling has to be carried out to complete the operation, but it is not a lengthy process and the job can be completed in less than 30 minutes.

Excellent accessibility is provided when the cab is tilted —it is locked in place by a pin being put through one of the hinged brackets. And even without tilting there is toad access to engine components by raising a panel covering the unit. This was done in a very short time and it included taking off first of all a panel surrounding the handbrake lever and the gaiter around the gear-change lever. For daily routine checking of water a small panel is provided below, the driver's seat; if it is necessary to check that the electric engine-oil gauge is functioning correctly, the panel over the hand-brake lever has to be removed for access to the dipstick.

For the road test the H was loaded with gravel and with three men in the cab the gross weight was 9 tons 6-42 cwt., which, with a kerb weight of 3 tons 15 cwt., meant that we were carrying a load of 5 tons 6.5 cwt. All the tests were carried out at this weight and the results obtained can be seen in the accompanying panel. Taking fuel consumption first of all, I thought that we would have obtained a tittle better figure, say, around 16-5 m.p.g. at 30 m.p.h., but the six-mile route used—on the A6 south of Luton—has one fairly severe hill which had an adverse effect. However, for normal main-road running, I think the overdrive-top gearbox or the alternative higher axle ratio, or both, would be more satisfactory and make for an improved fuel consumption.

As the acceleration figures show, performance was quite lively even though bottom-gear was not used on the through-the-gears runs. The lowest ratio was never needed at all on the tests, not even when checking hill-climbing performance, so it should be possible for most operators using the vehicle to get away with the overdrive gearbox and the higher-ratio axle. With these included in the specification I would guess fuel consumption to be at least 18 m.p.g. at about 30 m.p.h., and 17 m.p.g. at about 40 m.p.h. cruising speeds.

It is unlikely that with the optional gearbox and axle ratio, performance would drop appreciably. Through-thegears could even be improved: first-high gear with this layout will be almost exactly the same as second-low with the layout as on the vehicle tested, and the otherratios that would have to be used may give an advantage. There would have been a little worsening of the direct-drive figures—these were taken with the rear axle in the high ratio—and I feel that the engine would pull away from 10 rn,p.h. in direct drive quite well with a 5.125 axle ratio; it did so comfortably with the 5-85 to 1.

The braking figures obtained were very good, although there was some deviation from a straight line by the back end on the stops from 30 m.p.h. This was because of the rear wheels locking for the last part of the stops and the camber moving them towards the kerb. A little more braking effort at the front wheels, or a little Tess at the back, would improve the situation, but as the front wheels marked the road fairly heavily as well it was obvious that these wheels were almost at the point of locking. The handbrake, giving a Tapley-meter reading of 38 per cent, was very effective.

To see what happened when one air-pressure circuit was out of action, a pipe to one side of the dual actuator was removed and a maximum-pressure stop from 30 m.p.h. made. This produced a stopping distance of 75 ft. 9 in., representing an actual efficiency of 40 per cent as compared with an actual 70 per cent obtained on the stops with the complete system working. The stop was smooth and the vehicle completely in control, which may not have been the case if only the brakes on one axle had been actuated.

For the hill-climbing performance tests Bison Hill was used, this being 0.75 miles long and having an average gradient of 1 in 10.5. A non-stop climb was made in 3 min. 46 sec., and with the ambient temperature 1°C (34°F) the engine coolant temperature had risen from 45°C (114°F) at the bottom of the hill to 70°C (163°F) at the top. Second gear with the high rear-axle ratio was the lowest used on the climb, and the minimum speed was 10 m.p.h. To assess fade resistance the Austin was coasted down Bison Hill in neutral, with the ftx)tbrake applied to keep the speed to 20 m.p.h. Towards the bottom of the hill, where the gradient flattens out, top gear was engaged and full throttle applied with the brakes still on to keep the speed at 20 m.p.h. A full-pressure stop at the bottom of the hill -produced a Tapley-meter reading of 78 per cent, only 20 per cent less than the best cold-drum figures. Stop-and-restart were made on the 1-in-6-5 section of the hill, and both facing up and down the slope the hand brake held the vehicle easily. A restart up the hill in, second-high proved to be just beyond the capabilities of the 5-tonner—it was possible to move forward a short distance, but impossible to get the vehicle rolling. An easy restart in second-low was made and it was also found very easy to start off and reverse up the slope in the high rear-axle ratio.

It will be seen then that I found many good paints about the F.3 5-tonner. I would say that I have seldom been as pleased with any vehicle inthis weight category from the performance, ease of handling and the general driver comfort angles; in addition to the aspects already commented on, the ENV synchromesh gearbox was very easy to use—the synchromesh could not be faulted—and the suspension was good.

As tested, the F3 5-tonner with drop-side body costs £1,650 basic. The two-speed axle, which was the only option on the vehicle, added £60 to this price, and without the body the price is £145 less. In addition to the 12-ft. 7-in.wheelbase version tested, there are 9-ft. 3-in., 14-ft. 3-in. and 16-ft. 9-in. versions available. These are not obtainable with standard bodies and the basic price of the chassis/ cab versions are £1,490, £1,515 and £1,530 respectively.

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