Productivity is Seddon's forte
Page 33
Page 34
Page 35
If you've noticed an error in this article please click here to report it so we can fix it.
The new Secdon Atkinson 300 tipper is built for economy. As Bill Brock finds, it is capable of delivering. Pictures by Brian WeatheriE
PRODUCTIVITY, today's financial keyword, is the main reason for Seddon Atkinson's introduction of the 300-Series.
It fills a gap between the 200 and 400 models, and is designed for operation at 24 tons gross. When fitted with a lightweight body, such as the Edbro alloy welded version fitted to our test vehicle, it carries a payload of just under 17 tonnes.
The American influence is evident in the fitment of the DT-466 turbocharged diesel engine, a product of SA's parent company International Harvester. The unit is new only to SA and the UK. In America over a quarter of a million such units have been sold during the last seven years.
Rated at 144.7kW (194bhp) at 2,600rpm installed, it set a fuel consumption standard over our mixed site and road test route by which all future tippers will be compared. While maintaining an average speed over the 200km (124.3 miles) of 37,6km / h (23,4mph), the vehicle returned 42.7Iit/ 100km (6.6 mpg).
The engine is relatively uncomplicated. It uses a one-piece cylinder head separate from the integral block and crankcase, which has a deep skirt for added rigidity. An induction-hardening process is said to improve resistance against wear in both the lournal and fillet areas of the m-ankshaft. For prolonged engine life, the valve seats are angled at 30 and exhaust valves are stellite-faced.
Each valve turns through 17' on each operation, preventing a build-up of deposits. The wettype cylinder liners are replaceable and the pistons made from cast alloy. All rings are chromefaced. An American Bosch Jistributor-type fuel pump with a mechanical governor and
automatic advance mechan gives precise metering of fuel and hence clean emissio The Dana-Spicer 355i (14in) diameter twin-dry-p clutch, hydraulically opera and self-adjusting, is capabli transmitting more than twic( much torque as the DT-466 gine produces. The spr layout ensures near-const pressure on plates, irrespec of wear, and reduces pe effort as it is depressed.
The gearbox, ZF's AK 6is a six-speed constant-m, unit with gear positions i reverse pattern to normal Bri. practice. Constant mesh, vl fewer wearing parts, is accep as more reliable than the ei valent synchromesh design, is less convenient to use.
Both rear axles are locatec torque rods with sealed-for ball-joints at the ends, while foremost of the two is equip' with a power divider and an operated third differential loc The rear bogie is the Ea 380-Series double-drive mo over-slung by multi-leaf se elliptical springs with halal beam and slipper ends. section pins in the balance be are replaceable.
The separate braking circu front to rear, use nylon br pipes extensively. Type 24 , chorlock spring brake chamb are fitted to the versatile fr axle, which is comm throughout the range of b, the 400 and 200-Series. T, 30 brake chambers are fittec the rear bogie.
Braking, although smoc was hardly powerful. Over 4 (150ft) from 40mph represe a deceleration of only 0.3, This stopping distance is ab 50 per cent more than we pect from 32-ton vehicles.
Private cars are reasona expected to stop in less 21m (70ft) from 40mph in emergency which, 1 feel, p the whole picture into persp tive. Braking was otherw satisfactory.
Steering is power-assist
continued oven/
but too much so. Insufficient feedback from the road leaves one wondering just where the wheels are pointing when the going gets sticky. So light is it that I could easily rotate the steering wheel with my little finger. Seddon Atkinson plans to change the pump for one rated at 100psi instead of the existing 120psi.
Inside, the cab is finished in a pleasing light trim which may, however, prove impractical for muddy work. It is scrub-proof though. The floor is ocvered in a thick rubber mat which comes flush to the door aperture, so it should be easy to clean out.
Instrumentation is well laidout for easy inspection and includes such items as a battery condition indicator and fuel gauge. A tachograph was fitted to our test vehicle but it is listed as an optional extra. Calibration for speed and distance showed it to be very accurate.
A suspension seat is a must for on/off road work even when, as with the 300, the cab has its own suspension. The cab seat of the 300 is rubber /air damped. Adjustment seemed arbitrary but nevertheless ironed out the shocks over the rough site section and provided support in the backrest as well. The engine cowl intrudes into the interior between the seats but is low and serves as a central console with an oddments tray. Much of the cab above waist level is glazed. The large pane to the rear is Sundym glass which lets in sunlight but keeps the heat out. Door windows wind up to in /out air vents located at the tops. Triple windscreen wipers working from the bottom of the screen to clear a large area are matched by a row of sun-visors across the full width of the interior.
Entry is not as low as I would have liked but the two steps make regular to-ing and fro-ing less tiring.
What our test route lacks in length, it makes up with the severity of on-site running. Almost one-quarter of the total running is accounted for by the off-main-road section. Potholes, bends, steady gradients up and down and a few steeper sections give ample opportunity to test gearbox, brakes and steering to
their utmost. At best 25-30mph is possible, but at some stages the speed drops down to about 5mph. Steering is easy, but more feel is needed.
The gearbox, with the highest gears furthest away from the driving seat, presented no prob lem. Selection was assurec even where a fast changedown was needed to keep going on the steeper sections, Hill climbing from a standing start proved to be just better than the theoretical maximum.
Towards the end of the day, I tried the vehicle through some more severe conditions, including water and deeper mud. Only once was it necessary to engage the diff lock.
This was done while the vehicle was stationary, but it enabled us to resume the mudplugging quickly. The warning bell and light are a constant reminder that it is engaged and were an encouragement to manage without for as much of the time as possible. But it is satisfactory to know that a little more traction is available when needed.
It was a fatiguing day but no Dbvious vices had become apparent as it drew to a close.
Final inspection of the vehicle showed that it had stayed remarkably clean for the condi tions encountered. The Edbro body, filled to the brim with rock chippings, looked none the
Norse for the day's work. The cab, not surprisingly, is a corn
Dination of the 200 and 400
cabs. Although it tilts to a full 500, it needs to be raised only
or major services as everyday nspections for air and water can pe made from outside the vehicle.
Summary This is a vehicle made in the Seddon Atkinson tradition, Jiving an air of reliability above 311 else. The maximum brake application produced disappointing results but the vehicle cannot be faulted on power, comfort or tractability.
On return to the factory at Oldham, the load-sensing setting was rechecked and found to De restricting the air supply to the brakes by 50 per cent. This would most certainly explain the deficiency in deceleration.
The pto, mounted at the rear Pf the gearbox, is low but is out )f harm's way, as are the brake chambers positioned above the axles.
The engine does not lack in Dower, providing 8.1bhp per and has already proved .eliable in the USA. The light Edbro body with tipping gear weighs only 840kg, adding little :o the chassis weight, and is onstructed in a similar manner :o that of the 400-Series but without flitches.
The cab offers a good environment to the driver but is nigh above the ground for reguar access.
Priced at £23,963, it is a ood contender in its own sector pf the market.