Compare Furukawa HCR900-DS vs HCR900-DS2 with In-depth comparison CAT C7 vs CAT3126B

A comparison for used Furukawa drill buyers — by S. Suvit Trading, Furukawa specialist since 1968

Quick summary

The HCR900-DS and HCR900-DS2 are nearly the same machine — they differ mainly in the engine. The drifter, boom, guide shell, rod changer, drilling control system, and chassis are all identical.

• HCR900-DS uses the CAT 3126B (176 hp) engine

• HCR900-DS2 uses the CAT C7 (225 hp) engine — the direct successor to the 3126B

  
  

How to choose: Both engines come from the same family and use the same injection system (HEUI). The DS2 is more powerful and newer, but maintenance history matters more than the model number — a well-cared-for DS can beat a neglected DS2.

1. What's the same, what's different

Many people assume DS and DS2 are different models. In reality, the "2" simply means an updated version with a newer engine — the machine structure is almost entirely the same.

Identical: HD709 drifter, JF200 boom, GH831 guide shell, GR180 rod changer (4 rods), hydraulic drilling control system, Pentagonal chassis, PDS265 compressor, 65–90 mm hole range.

Different: the engine (3126B → C7) and the engine-speed modes — which is the heart of this article.

What this means for the buyer: almost all wear parts — the HD709 drifter seal kits, undercarriage parts, rod changer components, filters — are interchangeable between the DS and DS2. That's a real advantage if you run both in one fleet.

2. The engine — where the real difference lies

Both engines are CAT 7.2-litre inline 6-cylinder units from the same family — the C7 is the engine CAT developed directly from the 3126B in 2003, not a different line.

Item	CAT 3126B (HCR900-DS)	CAT C7 (HCR900-DS2)
Power in the drill	176 hp (131 kW @ 2,200 rpm)	225 hp (168 kW @ 2,200 rpm)
Torque (typical range)	420–860 lb-ft	520–925 lb-ft
Fuel system	HEUI	HEUI (updated)
Connecting rods	Forged steel	Powdered metal, fractured cap
Emissions standard	Tier II	Tier III
Production years	1998–2004	2003–2009

What the C7 improved over the 3126B: roughly 49 more horsepower (about +28%), larger water and oil pumps (better cooling), a more robust front gear train, and a faster ECM with ACERT technology.

The most important shared trait: both use HEUI

HEUI is an injection system that uses engine-oil pressure to actuate the injectors instead of a mechanical high-pressure pump. The consequence — which every owner of either model must understand:

Engine oil is the heart of the injection system — not just a lubricant, but the direct "driver" of the injectors. Use only CAT-spec engine oil Never extend the oil-change interval — this is the number-one cause of HEUI failure Dirty or degraded oil → damaged HEUI pump and injectors

Mechanics in the field agree on this point: a well-maintained HEUI engine runs a long time, but a neglected one becomes hard and expensive to repair.

3. Weaknesses of the CAT 3126B (in the HCR900-DS)

Strengths

• Parts are easier to find and cheaper — extremely common in trucks, buses, and equipment worldwide

• Forged-steel connecting rods — generally stronger than the C7's powdered-metal rods

• Well understood by mechanics in Thailand and the region

• With low-rpm, well-maintained use, over 20,000 hours has been reported

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Weaknesses / common problems

Problem	Symptom
HEUI pump failure	Power loss, hard starting, rough running (the number-one issue)
Injector failure/leakage	Black smoke, oil consumption, power loss, oil crossing into the fuel
Injector synchronization	⚠️ Requires a dial gauge and special tooling after any injector work; wrong setting causes knock/misfire
High-pressure oil line / crossover tube cracks	Oil leaks, pressure drop (seen on early units)
Low oil pressure / coolant leaks	Warning lights, overheating

Note: although it's the older engine, the 3126B is not a purely mechanical engine — it still needs CAT ET to read fault codes, unlike the ISUZU 6BG1 in the HCR9, which can be serviced with ordinary tools.

4. Weaknesses of the CAT C7 (in the HCR900-DS2)

Strengths

• About 28% more power — drills hard rock and sustains continuous work more comfortably

• Better cooling by design (larger water and oil pumps)

• Stronger front gear train

• Younger engine, more remaining service life, better resale value

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Weaknesses / common problems

Problem	Symptom / note
Overheating under sustained heavy load	Reports that the cooling fan engages later than ideal — watch the radiator carefully
Injector failure / misfire	Rough running, smoke, oil consumption (inherited from the HEUI family)
Never overfill the engine oil	⚠️ Causes excessive blow-by — fill toward the lower end of the range
CAT filters only	Oil and fuel filters must be to spec
More complex electronics	Harder to diagnose; requires CAT ET

On connecting rods — what most sellers won't tell you The C7 uses powdered-metal, fractured-cap connecting rods, while the 3126B uses forged-steel rods, generally considered stronger. In practice this is not a problem if the engine is run within rating and well maintained, but it's why some mechanics still prefer the 3126B — and a caution against any idea of "tuning for more power," which should not be done in a drill rig.

5. Engine-speed modes — a difference you can feel

Per the HCR900-DS2 factory spec sheet, it has a two-level engine-speed selector:

• Normal mode: 2,200 rpm

• Eco mode: 2,000 rpm

Eco mode reduces fuel use and noise on lighter work, while the auto-throttle raises rpm automatically when drilling/flushing begins and returns to idle on its own when the load clears — making the DS2 more economical and quieter overall.

6. Which one should you buy?

Choose the HCR900-DS (CAT 3126B) when:

• Budget is tight and you want the lower entry price

• You drill soft-to-medium rock, not heavy continuous work

• You want engine parts that are easier and cheaper to source

• You value the forged-steel connecting rods

  
  

Choose the HCR900-DS2 (CAT C7) when:

• You drill hard rock or work continuously and want power in reserve

• You want a younger engine with more remaining life

• Resale value matters to you

• You want the fuel-saving eco mode

  
  

Pre-purchase checks (apply to both, since both use HEUI)

1. Oil-change history — most important, because the oil drives the injectors; be wary if there are no records

2. Exhaust smoke — heavy black indicates worn injectors/HEUI pump; white-blue indicates oil consumption

3. Engine oil pressure — abnormally low directly affects the HEUI system

4. Blow-by — open the oil filler while running; heavy smoke pushed out means worn rings/liners

5. Cooling system — radiator, scale, coolant condition (especially important on the C7)

6. Read codes with CAT ET — required on both; have the seller show you

7. Hour meter vs. actual condition — implausibly low hours on an old machine often means the meter has rolled over

   
   

7. Conclusion

The HCR900-DS and HCR900-DS2 are the same machine differing mainly in the engine — the HD709 drifter, boom, guide shell, rod changer, drilling control, and chassis are all identical, so most wear parts interchange.

On the engine: the C7 is the direct successor to the 3126B — more powerful (225 vs 176 hp) and better-cooled, but with powdered-metal rods and more complex electronics.

What matters more than the model: both engines use HEUI, which relies on engine oil to drive the injectors. So maintenance history matters more than the model number — a DS2 whose oil changes were neglected can be worse than a well-maintained DS.

About this article

S. Suvit Trading Ltd., Part. has imported, overhauled, and serviced Furukawa hydraulic crawler rock drills since 1968. We sell Furukawa drills including the HCR900, HCR1000, and other models, with repair, genuine parts, and restoration of the control system back to original.

We write comparisons like this to be useful rather than flattering — including the weaknesses of both models — because a customer who buys the wrong machine does not come back.

If you'd like a machine assessed before you commit — including one you're buying from someone else — we're glad to inspect it.

S. Suvit Trading Ltd., Part. 704 Charoen Rat Road, Khlong San, Bangkok 10600 svtrade.com