Cover Story: 30- to 45-metric-ton excavators

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Updated Jul 6, 2020

Noting the strong emphasis on jobsite and individual environments, manufacturers of 30-to-45-metric-ton excavators are highlighting cleaner engines, fuel economy and comfortable operator environments. Faster hydraulics, simplified maintenance and new Tier 3 engines deliver a boost in productivity and lower daily costs. Ergonomically designed cabs and controls minimize operator fatigue. Here’s what’s new in this machine class.

Komatsu PC300HD-7
The base of the Komatsu PC300HD-7 is the rugged undercarriage of the PC400LC-7. “The configuration gives the PC300HD incredibly low ground pressure,” says Peter Robson, senior product manager, Komatsu. “It works well in soft underfoot conditions and gives you a stability advantage.”

The PC300HD has two boom mode settings: smooth mode and power mode add to machine’s stability, with 20-percent lift capacity. Pressing the machine’s Power Max button temporarily increases digging force by 8 percent.

Komatsu’s Komtrax system is standard on all Tier 3 excavators. Komtrax-equipped machines can send location, SMR and operation maps to a secure website using wireless technology. Machines can relay error codes, cautions, maintenance items and fuel levels.


Deere 350D LC
The John Deere 350D LC excavator retains many of its predecessor’s features. The D-Series’ faster hydraulic system boosts productivity by up to 8 percent, says Mark Wall, product manager for John Deere Construction. “Improved hydraulics ensure faster digging and more work per hour,” Wall says. “Drawbar pull, swing torque, lift capacity and arm force have improved significantly.”

More D-Series improvements include a redesigned cab with a fully adjustable suspension seat and extra legroom. Forty-seven percent more right-hand window glass and a larger roof-hatch area give the operator a full view of the entire work area. The monitor features easy-to-read gauges, warning lights and icons that provide operating information at a glance. Easy-to-navigate screens provide access to warning messages, attachment preferences and maintenance and service information.

The 350D LC John Deere PowerTech engine employs a four-valve design that enhances fuel economy. Lowered exhaust gas recirculation cools combustion by reducing oxygen without timing retard. The hydraulically driven cool-on-demand fan runs only as needed, reducing noise and operating costs.

The access to remote-mount oil and fuel filters, located in the pump compartments, simplifies maintenance.


Hitachi Zaxis 350LC-3
A combination of the HIOS-3 hydraulic system and the new OHC four-valve engine allows the efficient use of hydraulic pressure to increase speeds of actuators and boost production with higher fuel efficiency. The new E mode, H/P mode and P mode match job needs. The E mode can save 15 percent more fuel than the previous P mode, while yielding similar production.

The oil cooler, radiator and intercooler are in a parallel design for easier cleaning around the engine. Oil and filter change intervals are longer. Engine oil changes are recommended every 500 hours, hydraulic oil at 5,000 hours and the hydraulic oil filter is good up to 1,000 hours.

You can see what is behind the machine on the widescreen color LCD monitor. The redesigned ZAXIS-3 series cab has ample legroom, short stroke levers and a heated suspension seat with horizontal, vertical and weight adjustments. Foot space is increased and redesigned brake pedals allow easier operation.


Cat 330D L
The 330D L has more engine power and increased hydraulic pressure for increased breakout force and greater lift force. A heavy lift circuit for added lift performance is standard. The 330D L has 268 horsepower, 9 percent more than the 330C L. Cat’s C9 ACERT engine powers the 330D L.

The machine’s ADEM A4 engine management system has flexible fuel mapping, allowing the engine to respond quickly to varying application needs. For reduced power consumption and noise, the 330D L has a hydraulically driven fan controlled by the electronic control module. Fan speed varies depending on the demand for cooling.

The 330D L has a wide range of factory-installed auxiliary hydraulic systems, including a one-way, high-pressure, high-flow circuit for hammers and vibratory plate compactors. A two-way circuit is available for thumbs and other hydra-mechanical work tools. Using the in-cab monitor, the 330D Tool Control System option allows you to pre-set and store flow and pressure settings for 10 different hydra-mechanical work tools.

The hydraulic system in the 330D L has a component layout that minimizes the lengths of lines and tubes to reduce heat and sound around the cab. The 330D L uses a hydraulic cross-sensing system to maximize hydraulic power when needed for faster implement speeds. An auxiliary hydraulic valve is standard on each machine. Control circuits available as attachments allow use of high-and medium-pressure tools.

The 330D L Tool Control System comes in two factory-installed configurations – as a stand-alone system or with a medium pressure circuit and third pump. The latter system handles tools that require rotate function, such as multiprocessors or rotating grapples. It also can handle hammers, thumbs and similar tools. Single and double-function hydraulic tool systems are available as a factory installed attachment.

The 330D L cab has an optional air suspension seat with heater. The automatic climate control adjusts temperature and airflow, determining which air outlet is best in each situation. The full color display, which Cat says is easier to read and navigate than the C-Series monitor, adjusts to minimize glare. Pillar-mounted wipers increase the viewing area.


Liebherr R944C
A Liebherr D 935 L inline six-cylinder diesel engine drives the R944-C Litronic, producing 258 horsepower at 1,800 rpm. Four operating modes match engine and hydraulic output to achieve maximum production and efficiency. The Liebherr Diesel Engine Control management system monitors all performance parameters and adjusts the settings based on a continuous analysis of the engine’s performance.

Two different mount positions let you adjust the digging envelope or lifting capacities of the machine to the application. Improved attachment geometry creates high digging and breakout forces with short cycle times.

C series excavators have hoist cylinders with integrated load-holding valves, which allow gravity to lower the boom instead of hydraulic pressure. The load-holding valves prevent the boom from lowering on its own, and the operator controls the lowering rate with the joystick. This lets either more or less oil flow back into the hydraulic circuit. As a result, the full hydraulic system can be used for other functions, or can be idle, thus saving energy. Bypass valves integrated into the main control block enable the R944C to perform simultaneous travel and lifting duties without loss of flow or pressure to any function.

The redesigned cab of the R944C features laminated safety glass and a single piece right-hand window to increase visibility and safety. Extra guarding is available for the cab to maximize safety and optional balancer shafts lower the amount of structurally transmitted noise.

Standard semi-automatic centralized lubrication allows you to grease all lube points without leaving the operator’s seat.

For specialized applications, Liebherr offers a wide variety of booms, sticks and buckets, including long- reach backhoe and high-reach demolition attachments. The machine can be programmed to tailor its hydraulic supply characteristics for up to 10 different attachments.


Additional machines in this class CASE CX330
A Tier 3-certified electronic Isuzu engine powers the upgraded CX330. The engine uses a common high-pressure rail system that results in a 5-percent increase in horsepower and 8 to 10 percent better fuel economy over previous models.

Increasing the strength of the front idlers beefs up the thickness and design of the center hub and improves the track seal design for increased life.

The CX330 has an EMS (easy maintenance system), and lubricated and impregnated bushings throughout the boom and arm for extended lube intervals of up to six months or 1,000 hours. The engine oil filters in the pump-house area allow for easier access and service. The addition of a “green” plug – a modified oil pan drain plug with a check valve – further facilitates oil changes. The adapter on the plug automatically goes through the check valve and through the hose, eliminating the likelihood of spills. The machine’s cooling system design reduces the stacking of coolers for better cooling efficiency and improves access to ease debris removal.


Volvo EC360B LC
This machine’s turbocharged, six-cylinder engine uses Volvo Advanced Combustion Technology and includes high-pressure fuel injectors, internal recirculation of the engine exhaust and electronic controls.

Contronics, Volvo’s advanced mode selection system, controls four different hydraulic power modes with different engine rpm: Mode H (heavy) for high productivity jobs; Mode G (general), which offers both high productivity and fuel savings; Mode F (fine) for lifting power and precision work; and Mode I (idling) for use in low-noise situations.

The operator’s air-ride seat is heated, adjustable and includes control consoles that move independently. The automatically controlled integrated air conditioning and heating system blows filtered air from 13 vents.

Service features include high filter capacities for longer service intervals, a quick and common oil drain with valve and a hinged-type cover to access the engine oil filter. Previous Volvo excavators had a three-stage air cleaning system to keep dust and dirt out of the intake system. New to EC360B LC is a high-performance oil-bath pre-cleaner for effective particle filtration.


Link-Belt 330 LX
The Link-Belt 330 is powered by an Isuzu AH-6HK1XYSS 271-horsepower, six-cylinder, four-cycle diesel engine, using a common-rail fuel injection system, a fuel cooler and turbocharger with intercooler.

The 330 LX wide cab sits on six silicon-filled isolation mounts that float the cab above noise and vibration. The KAB 515 semi-bucket seat slides independently of the control consoles. A large LCD monitor displays engine temperature, hydraulic oil temperature, fuel level, travel speed, work mode and engine idle. Messages include system/machine warnings and service due messages in 14 languages. The cab’s rear and side windows are made of Lexan Marguard. Standard vandal covers protect the safety glass front windows and stow on top when the machine is working.

The 330 LX’s Inte-LX computer control system monitors hydraulic output, pressures, and regulates engine performance. The auto power-up function automatically supplies a power increase without operator interaction and regardless of the work mode. Hydraulic pressure sensors detect resistance and increase pressure 9 percent for 8 seconds. There are five work modes: Heavy for heavy excavation and extra power; Standard for standard operations reducing fuel consumption; Lift for lifting operations, and an Allied Attachment mode for using attachments. The Auto Mode presets engine rpms to match hydraulic requirements.

Inte-LX’s on-board diagnostic system allows service personnel to analyze 148 items in four categories. The Inte-LX system has a password-protected anti-theft device.

Oil and fuel filters are vertically mounted. The 330 LX has a green plug for draining engine oil to prevent spills. The Nephron Filtration System eliminates contaminants of 1 micron or more in size. Hydraulic fluid in the 330 LX can be changed every 5,000 hours.


Kobelco SK350LC
The new SK350LC Acera Mark 8 is powered by a 264-horsepower electronic fuel-injected Hino engine.

“A major change in this model is the excavator’s controllability,” says Paul Golevicz, brand marketing manager, Kobelco. “Designed for heavy digging, the SK350LC can also perform smooth finishing and grading.”

A power boost switch on the SK350LC excavator releases 10 percent more power on command for increased bucket breakout force. The Independent Total Control System gives smooth response of hydraulic controls for fine finishing and grading applications.

Goleviciz says, “All major controls – including double-flow hydraulics for powering tools and attachments, mode selection switches and heavy lift and independent travel switches – are located on the operator’s right side for easy access.”

To reduce maintenance time and boost productivity, all routine servicing and fluid checks are easily performed from ground level, with access to filters, batteries, sight gauges and couplers.