Caterpillar's latest and largest G Series scraper — the 657G — features Tier III-compliant ACERT engines. Dual horsepower capabilities of 451/410 at the rear and 600/564 at the tractor produce more power in higher gear ranges for fast cycle times.
Caterpillar's 657G waits on the sprawling shore of the Pacific. Operated by Sukut Construction, one of California's largest contractors, this machine is one of four pre-production units Cat has working in the United States. Its current job: to move dirt on the future site of high-value homes in California. Industry editors and contractors look on.
The largest of the company's eight G Series scrapers, the 657G rolls down an incline and loads dirt around a steep corner. Seconds later, it turns and glides back up the hill to dump the load. After several trips, it's hard not to notice how quickly the machine moves dirt. In this instance, loading takes about a minute. Loading and cycle times vary, of course, depending on ground conditions, material, and operator skill, among other conditions.
After completing the demonstration, the machine parks for its audience to have a kick at the tires. First stop: the scraper bowl. Capable of cutting to 16.7 inches deep with a maximum spread depth of 26.8 inches, the bowl holds a 104,058-pound load. Heaped bowl capacity is 44 cubic yards.
The machine's rear engine is a Tier III-compliant C15 ACERT, rated at 451/410 horsepower. With dual horsepower capabilities, the engine can produce more power in higher gear ranges for optimum gradeability and reduced cycle times, says Caterpillar.
The rear engine is a 6-cylinder, as opposed to the previous 657E model, which used 8- and 12-cylinder engines for the scraper and tractor, respectively. Caterpillar claims that providing more room in the engine compartment allows easier servicing.
Moving to the other end of the machine, the tractor uses a Tier III-compliant ACERT engine. The C18 is rated at 600/564 horsepower and has six cylinders.
Like the ACERT engines, the radiators occupy less space, thus providing increased space for service access. Both the tractor and scraper feature the company's Next Generation Modular Radiator (NGMR). NGMR increases spacing by lowering fins per inch from 33 (in the previous 657E model) to 9. With this increased spacing, Caterpillar aims to reduce radiator clogging in severe applications.
Additional serviceability improvements include a hinged tractor grill and two side panels that open to the radiator core. Two side doors on the right side of the machine provide access to service points. To get to the engine bay, the operator opens a hinged hood with support from spring struts.
Caterpillar has improved ease of operation as well. First, the G Series cab is more comfortable. An air-suspension seat features four swivel-lock positions for proper positioning in relation to the controls. Second, the three levers for bowl, apron and ejector are combined into one joystick to simplify operation. The joystick has a rocker switch for the push-pull bail or auger activation, and a combination grab handle and hand rest is located near the joystick to help steady the operator's arm.
