ACCESSIBILITY PLUS
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RFORMANCE
By A. J. P. WILDING
New Commer Walk-Thru Two-ton Van with Three-litre, Six-eylindered Petrol Engine Proves Lively, Well-sprung and Admirably Stable
FROM the point of access to the load and driving area, the Commer Walk-Thru range of light goods vehicle (described in The Commercial Motor, October 13, 1961) is probably better than any other load carrier currently available. But this is not the only thing for which the design can be commended. The model tested was the 2-ton van, fitted with the 3-litre petrol engine. Suspension, steering and stability were found to be excellent under all load conditions, braking was good, and the comparatively large engine gave good acceleration and, considering its size, reasonable fuel consumption.
No driver would in my view be justified in criticizing the van, for apart from the ride and performance, all controls are well placed and light. The clutch and brake action is good—the steering-column-mounted handbrake lever being particularly easy to reach and apply. Vision is extremely good, with a large two-piece windscreen—the centre and corner pillars are not obtrusive—and generous windows in the sliding doors which extend a good way behind the driver's head.
The 3-litre engine fitted to the model tested is a derated version of the six-cylindered unit fitted in the Humber Super Snipe car. Bore and stroke dimensions are 87.3 mm. and 82.5 mm. respectively. Maximum power output is 79 b.h.p. at 3,800 r.p.m. and maximum net torque is 147 lb.-ft. at 1,400 r.p.m. Compression ratio is 6.5 : 1, compared with 8.0 : 1 for the Super Snipe version, and it is interesting that, whilst the maximum power output is reduced by over 30 per cent. and is obtained at a speed 1,000 r.p.m. lower, than the car unit, maximum torque is reduced by only10 per cent., at 400 r.p.m. lower down nt 2
the scale. As is to be expected, the fitting of this •engine results in admirably quiet performance.
Transmission is through the same four-speed gearbox (with synchromesh on the top three ratios) that is used in the earlier design of Conarner 1and 14-ton vans which are, incidentally,, still in production. Gear changing was actually the only point on which the Walk-Thru van tested could be criticized. When the change was made too quickly, the engagement of the gear was relatively heavy and it was possible to overcome the synchromesh. This was'more in evidence when engaging second gear. Normal gear • changes, however, were quite light and the synchromesh action was good. It was, in fact, found possible to change down to second gear at a road speed greater than the maximum in that gear when the change was made correctly. •
Controls Well Placed
All driving controls are well placed and easily accessible without stretching. The head and side light switch is combined with the 'ignition switch on the. instrument panel, where there are also toggle switches for the windscreen wipers and panel light. In the centre of the panel is the speedometer, which incorporates also water, temperature and fuel gauges and main beam, oil pressure and ignition Warning lights. The speedometer can be read without trouble through the steering wheel spokes.
At the top of the steering column, on the left-hand side and beneath the handbrake lever, the lever-type dipper switch is located. Flashing direction indicators were fitted on the van tested and the control for these was an the opposite side of the column. As the indicators are not self-cancelling or controlled by a time switch, it was an advantage that the panel-mounted warning light was bright enough to be seen in daylight.
Other extras fitted on the van tested were rear bumpers with the central step section, and twin heating and demisting equipment. The latter was found to be very effective and even though the tests were carried out on a fairly cold day, it was necessary after a time to close the hot-air outlets in the cab. .
• The load for the tests consisted of a mixture of concrete blocks and sand-filled sacks, evenly distributed over the floor area with a total weight of 1 ton 191 cwt. With two passengers and driver, the gross laden weight of the van was 4 tons 11 cwt. which meant an overload of exactly 1 cwt. Full-load fuel-consumption tests and all other tests were carried out at this weight. Weight distribution was 1 ton 81 cwt. over the front wheels and 3 tons 21 cwt. over the rear wheels. The 6.50-16 (8-ply) tyres were therefore within their capacity by about 51 cwt., both at front and rear.
Because the body floor of the Walk-Thru is completely flat from front to rear there is nothing to stop the load sliding forward when braking. That there is a need for a stop of some sort was evident, as the stout timber beam wedged across the width of the body in front of the load was found to be slightly bowed by the force of the load moving forward even before the full-pressure braking tests.
Consumption Tests
For the fuel-consumption tests, the six-mile out-and-return run on the A6 road between Barton and Clophill was used. The figures obtained appear reasonable for a van of this capacity, particularly with such a large engine. The fact that there is, if anything, too much power available is shown up well by the small difference in consumption for the non-stop and ne-stop-per-mile runs when fully aden. The difference of only 1 m.p.g. indicates that little extra petrol was used in getting back to the normal running speed of 30-33 m.p.h. aimed at on these tests.
Figures for the oneand four-stops-per-mile runs with a full and part load are to all intents and purposes identical. It is also notable that the average speeds for the runs in the two load conditions are also very similar. This confirms the impression obtained when driving the van on the tests when the difference in the loading was hardly noticeable. In comparing the results with those obtained with other vehicles, the figures for gross ton-m.p.g. and
time-load-mileage factor are useful. Those for the van tested are about average.
The high-speed consumption run was made on the M1 motorway over a distance of 10.6 miles-from the A505 entry south to the A4147 junction. The ability of the 3-litre engine to keep the van running at or near its maximum road speed of 57 m.p.h. in spite of the comparatively severe southerly run from A505 is shown by the average speed of 50 m.p.h.. attained. At this speed the wind has a big effect on consumption and it was therefore fortunate that when the run was made the strong, blustery wind was coming straight across the motorway. Considering all the factors, the figure of 11.2 m.p.g. was quite good.
On the return motorway run, maximum speeds in the gears were checked and the accuracy of the speedometer was calculated. With the speedometer reading 3 per cent. fast at 30 m.p.h. and 5 per cent, fast at 60 m.p.h., actual maximum speeds in the four gears were found to be 15, 29, 49 and 57 respectively.
In assessing the probable fuel consumption of the van when used on general delivery work I would say that a figure of between 15 and 16 m.p.g. should be obtained. It is also very likely that a driver with a heavy right foot would not produce much lower figures-although the racing type may. Improved figures might be obtainable if the e14 acceleration pedal spring were a little stronger. I found the spring on the van tested very light, and it was very easy to give more throttle opening than was actually needed at any particular time Figures obtained for acceleration through the gears are above average for a vehicle of this load capacity, being as good as many obtained with 15-cwt. vans and better than most for 1and I -1--tonners. Direct-drive acceleration times are equally good-the result of a good pick-up from the low speed of 10 m.p.h. in top gear.
Braking tests were completed on the same stretch of road as those used for acceleration, a quiet lane just off the A6 at the start of the fuel-consumption runs. The road is as straight and flat as it would be possible to get and the surface is smooth tarmacadam. Under crash-stop conditions, the 2-tonner was completely stable from both 20 and 30 m.p.h. There was not excessive weight transference to the front wheels and from both speeds all wheels marked the road evenly.
On the stops from 30 m.p.h. all the wheels locked so the figures obtained were not as good as may be obtained on a different road surface.
The actual stopping distances of 44 ft. from 30 m.p.h. and 18 ft. from 20 m.p.h. are quite good. Tapley-mete readings taken 'showed a maximum braking efficiency of 88 per cent. from 20 m.p.h. and 83 per cent. from 30 m.p.h. The steering column-mounted handbrake lever proved to be very effective and handbrake efficiency—obtained using the Tapley meter—was 47 per cent., which is extremely good.
Hill-performance tests were the last carried out, Bison Hill being used for them. This is three-quarters of a mile long, has an average gradient of 1 in 104 and a maximum gradient of 1 in 6+. Ambient temperature was 52°F. and a fast maximum-power ascent of the hill was made in 2 minutes 31 seconds. Second gear, was the lowest used, being engaged for I minute 4 seconds and the minimum speed was 10 m.p.h. During the ascent the water temperature of the radiator top tank increased by 15°F.
Brake-fade characteristics were assessed on the run down the hill. The usual procedure was adopted, with the descent being made in neutral and the footbrake applied to keep the speed down to 20 m.p.h. The gradient towards the bottom of the hill is less steep and top gear is engaged and full throttle applied to keep the speed at 20 m.p.h. with the brakes still on. Total time for the descent was 2 minutes 42 seconds, of which 37 seconds were spent in Fop gear. At the end of the run, a full-pressure stop from 20 m.p.h. gave a Tapley-meter reading of 76 per cent. There was a little extra brake-pedal travel, which showed that the small amount of brake fade (the reading was 12 per cent. less than with cold drums) was due to expansion of the drums.
Easy Restart in Bottom Gear Following the fade test the van was taken up the hill md was restarted easily in bottom gear on the 1-in-6; ;ection. It was almost possible to restart in second, but ilthough the vehicle could be held on the clutch, the hill as just too steep. The handbrake held the load without my effort and with seven notches to spare. Commers say hat the model as tested is capable of climbing a gradient af 1 in 31 in first gear and this is quite justifiable. When ;oing down the hill the van was stopped on the steepest ;ection and a start in reverse was made—as a formality, aecause the reverse gear has a lower ratio than bottom. Needless to say, the van started comfortably.
in the same way that drivers of the Walk-Thru range ave• been given every consideration, so have they and echanics been catered for in the degree of accessibility or maintenance tasks incorporated in the design. Also to owner's credit is that they are one of the few British chicle manufacturers who supply a comprehensive kit of ood quality tools, including, besides a ratchet jack, four open-ended and one ring spanner, an adjustable spanner, a cabinet screwdriver, pliers and a special plug spanner.
When the full-width bonnet top is opened, all engine items requiring regular attention are within easy reach. Removal of the interior engine cowl is necessary only when the rear sparking plugs have to be removed or access to the cylinder head is needed. In timing the various jobs carried Out from the front the time taken in opening and closing the bonnet was included. These were checking engine oil level, which took 49 seconds; checking air cleaner oil level, 1 minute 43 seconds; topping up all cells of the battery, 1 minute 47 seconds; and checking the level of the brakefluid reservoir, 29 seconds.
No Starting Handle
Changing No. 1 sparking plug took 2 minutes 25 seconds and checking the distributor contact-breaker points gap needed only 1 minute 15 seconds. As no starting handle is supplied when the 3-litre engine is fitted—one could not be used easily for although the engine has a starting dog and there is an access hole in the front grille there is no guide fok the handle—the points were opened by rotating the fan.
Moving inside the van, No. 6 sparking plug was changed in 2 minutes exactly. This included the time taken in removing and refitting the interior engine cover. The gearbox has a dipstick, reached through a rubber plug in the cab floor. The time taken for an oil-level check was 26 seconds. The rear-axle oil level was checked in 1 minute 15 seconds from underneath the van.
The final task undertaken was adjusting the brakes on the off-side front wheel. The total time taken was 3 minutes 21 seconds, made up of 19 seconds getting the jack and handle from their positions under the bonnet, 1 minute 18 seconds to jack up the axle, 47 seconds to adjust the brake shoes, 35 seconds to lower the axle and 22 seconds to put back the jack and handle.
Basic price of the 2-ton Walk-Thru van with the 3-litre petrol engine as tested is £947. Considering the features incorporated to make the vehicle as near the ideal delivery van as possible, this price seems most attractive. The price when the 2.26-litre four-cylinder petrol engine is fitted is reduced by £58, and it is very likely that the van will be sold in this form in this country more than with the 3-litre unit. I would say that the main market for the version tested will be overseas, where longer journeys are more likely and above-average performance is required with fuel consumption not of paramount importance.