SK350 vs PC400: How 35 ton diggers often beat 40 ton beasts

Buying used excavators is a numbers game. On paper, a classic 40-ton digger such as the Komatsu PC400 looks like the safe bet: 345 hp, a 1.7-2.8 m³ bucket, and breakout force north of 190 kN. However, when put next to a Kobelco SK350LC-10, the 35-ton excavator that sneaks under 38 t, real-world economics start to swing the other way.

Why? Because most civil, road, and utility jobs don’t pay for metal weight; they pay for tonnes moved per hour, time on site, and how little grief the machine causes in travel, fuel, and repairs.

Muscle vs mobility

* Specs collected from Komatsu and Kobelco websites respectively. ** See more below.

That extra 75 hp on the Komatsu PC400 excavator is handy when you are placing 1,000-mm pipes or demolishing with a 3-ton shear, but the lighter Kobelco SK350 excavator puts 25% less load onto pavement and soft terrain. When city engineers bill you for asphalt depression, 3 psi matters more than 75 hp. 

Swing speed tells a similar story. Field tracking showed the Kobelco SK350 digger averaging 18-second dig-swing-dump cycles, only two seconds behind the bigger Komatsu PC400 digger despite using a smaller bucket. Over a ten-hour shift that’s roughly 1,280 cycles for the SK350 and 1,350 for the PC400. Seems negligible? Almost, but when fuel is a consideration, you’ll see which one shines.  

Fuel and operating costs

Telematics pulled from mixed-duty fleets give a big-picture truth:

• Komatsu PC400: 28 L h¯¹ average, peaks of 45 L h¯¹ (in mass excavation)

• Kobelco SK350: 22 L h¯¹ average, peaks of 30 L h¯¹

At the UAE’s July diesel price of AED 3.01 L¯¹, Kobelco saves about AED 180 every ten-hour day. Spread over a 1,600-hour a year that is AED 288,000, enough to buy six brand-new GP buckets more-or-less.

Add the USACE “all-in” owning-and-operating numbers (converted to dirhams): roughly AED 316 h¯¹ for the PC400 versus AED 432 h¯¹ for the Kobelco. On the surface Komatsu looks cheaper per hour, yet when you look at material actually shifted, the script flips. A cost-per-ton model put the PC400 at AED 0.77 t¯¹ and the SK350 at AED 0.63 t¯¹ once fuel was included.

In transit: Transport, uptime, and keeping the job going

Transport is often the hidden killer. A Komatsu PC400 excavator requires being transported on a tri-axle low-bed trailer, which is roughly (~37,200 kg). That means permits, maybe a follow car, and almost always off-peak moves in urban centers. 

The Kobelco SK350 digger, however, with its cab folded and bucket tucked, rides a trailer comfortably within regulations, which means no permits and same-day redeployment from a yard to any location three towns over. Bottomline is: less red tape = more paid hours.

Uptime shows the same pattern. The PC400 stretches its engine oil change interval to 500 h and hydraulic filters to 1,000 h. Great on paper, but each service still needs an overhead gantry or tall service truck. The SK350, with its ground-level iNDr filter stack and 250 h oil change interval, has a mechanic in and out in half an hour. For small contractors who wrench in the yard on Friday, easy service beats long intervals.

Ownership: wear and service factors

*** GCC Kobelco SK350LC-10 comes with a Hino engine.

Every excavator needs pins, chains, oil, and bucket teeth, but moving four fewer tonnes through the cycle extends everything down-stream: bushings, swing gear, even operator fatigue. Toss in the SK350’s graphite-impregnated bucket bushings, means no grease gun until 500 h, reducing daily chore time.

What questions you should ask

• ​​How many mobilizations a month?

If the answer is more than four: permit and pilot-car fees means the SK350 keeps the money in your pocket.

• How soft is the ground?

Anything under 150 kPa bearing favours the 35-ton excavator.

• Who pays for diesel?

On hourly jobs you do, and 6 L h¯¹ difference stacks fast, meaning favor goes to the SK350.

• What attachments already sit in the yard?

Both machines share 90-mm pin families, but cycle time suffers if you attach a 3-t hammer on the 35-ton machine.

• Can downtime be absorbed?

Longer Komatsu intervals are attractive, yet a missed filter change often spirals into a five-figure hose-pump disaster. Ground-level access on the Kobelco makes errors less likely.

Final call

The Komatsu PC400 is the right machine if you are breaking rock in a quarry, swinging heavy shears on a demolition site, or loading 40-ton dumpers all day. Raw power, bigger bucket, done. 

But day-to-day civil work is never that neat. Fuel is expensive, permits are slow, and often expensive, and customers call at 6 p.m. begging for a machine across town by sunrise. In that world the Kobelco SK350LC-10; still a “large” excavator on any rental card, delivers 90% of the production with lower diesel burn, fewer track-marks on the asphalt, and service tasks a one-man crew can finish before sundown.

Strip away the spec-sheet talk and you find the lighter 35-ton Kobelco SK350 excavator quietly winning the ownership race. If your buying decision is between “bigger bragging rights” and “better bottom line,” the data tips the scales: choose the SK350 and keep the change.