Eagle-powered Big J
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• British Road Services are shortly to take delivery of 25 Guy Big J 32-ton-g.t.w. tractive units powered by Rolls-Royce Eagle 220 naturally aspirated diesel engines with a capacity of 12.17 litres. And Guy Motors Ltd. has announced that Big J 30 /32-ton-gross tractive units having a wheelbase of 9ft 6in. are now available to the transport industry equipped with this power unit as an addition to the Big J range. The Eagle develops 220 bhp at 2,100 rpm (maker's gross rating) which is the same output and speed rating as the Cummins 220 diesel that is fitted to other 32-ton-gross models. The maximum gross torque of the Rolls-Royce diesel is 605 lb.ft. at 1,400 rpm while its compression ratio is 16 to 1. It has a bore of 130.175mm and a stroke of 152.4mm.
. Other details of the tractive unit remain unchanged and include an hydraulically operated 17in. dia clutch and a fully constantmesh air-pressure-assisted six-speed gearbox with over-drive top providing ratios of 7.17. 4.45, 2.54, 1.53 and 1.0 to 1, the sixth
The Rolls-Royce naturally aspirated Eagle 220 develops 220 bhp at 2,100 rpm and has a maximum torque output of 605 lb, ft. at 1,400 rpm. Power is transmitted through a standard six-speed gearbox with overdrive top gear.
speed being 0.75 to 1. Reverse is 7.5 to 1.
The 10-ton rear axle has epicyclic hubreduction gears and the standard final-drive ratio is 6.75 to 1, ratios of 6.35 to 1. and 5.524 to 1 being optionally available. Having a capacity of 61 tons, the front axle is plated at 6 tons while the steering is of the recirculatory ball type, which can be supplied with power assistance. The full-air braking system incorporates spring-actuated secondary and parking brakes, the front and rear brakes both having a diameter and width of 15+in. and ]in. respectively, which provide a total braking area of 844 sq. in.
Overall length of the vehicle is 16ft Sin. while the overall laden height is 8ft 7 kin. The distance from the rear of the cab to the end of the frame is about lift.