DCEC Cummins B3.9 Construction Machinery Engine — 80 to 130 HP Turbo Diesel
The DCEC Cummins B3.9 is a 3.9-liter, 4-cylinder inline turbo diesel engine purpose-built for construction machinery. Developed by the Dongfeng Cummins Engine Company (DCEC), this engine delivers 80 to 130 HP with peak torque up to 510 N·m, powering excavators, wheel loaders, bulldozers, road rollers, cranes and pump sets across mining, quarrying and infrastructure projects worldwide.
With 16 models spanning naturally aspirated, turbocharged and turbocharged-intercooled configurations, the B3.9 platform offers flexible power matching for equipment manufacturers and fleet operators who need reliable diesel power in compact, demanding applications.
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Request a Quote →Key Specifications
- Engine Type
- 4-Cylinder, Inline, 4-Stroke Diesel
- Displacement
- 3.9 L (238 cu in)
- Bore × Stroke
- 102 mm × 120 mm
- Power Range
- 80 – 130 HP @ 1,900 – 2,500 RPM
- Peak Torque
- 330 – 510 N·m @ 1,300 – 2,200 RPM
- Aspiration
- Turbocharged / Turbocharged-Intercooled
- Fuel System
- Rotary Fuel Injection Pump
- Cooling System
- Water-Cooled
- Dry Weight
- 500 – 600 kg
- Packing Size
- 1,110 × 910 × 1,350 mm
All B3.9-C Construction Machinery Engine Models
The B3.9-C series includes 16 models across three aspiration types. Each model is available as a complete engine unit or spare parts. Click any model for full technical data.
Turbocharged Intercooled (4BTAA3.9-C)
| Model | Rated Power | Peak Torque | Speed |
|---|---|---|---|
| 4BTAA3.9-C130 | 130 HP | 510 N·m | 2,200 RPM |
| 4BTAA3.9-C125 | 125 HP | 480 N·m | 2,200 RPM |
| 4BTAA3.9-C115 | 115 HP | 378 N·m | 2,200 RPM |
| 4BTAA3.9-C110 | 110 HP | 500 N·m | 2,200 RPM |
| 4BTAA3.9-C100 | 100 HP | 400 N·m | 2,200 RPM |
| 4BTAA3.9-C80 | 80 HP | 370 N·m | 2,200 RPM |
Turbocharged Intercooled (4BTA3.9-C)
| Model | Rated Power | Peak Torque | Speed |
|---|---|---|---|
| 4BTA3.9-C130 | 130 HP | 475 N·m | 2,500 RPM |
| 4BTA3.9-C125 | 125 HP | 475 N·m | 2,200 RPM |
| 4BTA3.9-C120 | 120 HP | 460 N·m | 2,200 RPM |
| 4BTA3.9-C110 | 110 HP | 460 N·m | 2,200 RPM |
| 4BTA3.9-C100 | 100 HP | 410 N·m | 2,200 RPM |
| 4BTA3.9-C80 | 80 HP | 360 N·m | 2,200 RPM |
Turbocharged (4BT3.9-C)
| Model | Rated Power | Peak Torque | Speed |
|---|---|---|---|
| 4BT3.9-C110 | 110 HP | 330 N·m | 2,600 RPM |
| 4BT3.9-C105 | 103 HP | 330 N·m | 2,800 RPM |
| 4BT3.9-C100 | 100 HP | 330 N·m | 2,400 RPM |
| 4BT3.9-C80 | 80 HP | 330 N·m | 2,000 RPM |
Why Choose the B3.9 for Construction Machinery?
High Torque at Low RPM
Construction equipment needs pulling power, not peak horsepower. The B3.9 delivers up to 510 N·m of peak torque at speeds as low as 1,300 RPM, giving excavators and loaders strong breakout force and hill-climbing ability without constant downshifting.
Built for Harsh Conditions
Construction sites are dusty, hot and demanding. The B3.9 features a platform honed cylinder liner that reduces friction and extends service life, a Holset turbocharger with exhaust wastegate for consistent boost under variable loads, and a heavy-duty air filtration system designed for high-dust environments.
Fuel Efficiency That Cuts Operating Costs
The rotary fuel injection pump delivers precise fuel metering for optimal combustion. Across a typical 2,000-hour working year, B3.9 engines consume 10–15% less fuel than comparable displacement competitors, directly improving your project margins.
Compact Package, High Power Density
At just 500–600 kg dry weight and compact dimensions (1,110 × 910 × 1,350 mm), the B3.9 fits into the engine bays of compact excavators, skid steers and small wheel loaders where space is at a premium.
B3.9 vs. Competing Construction Engines
| Parameter | Cummins B3.9-C | Yuchai YC4D | Weichai WP2.3 | Kubota V3800 |
|---|---|---|---|---|
| Displacement | 3.9 L | 4.2 L | 2.3 L | 3.8 L |
| Power Range | 80 – 130 HP | 75 – 140 HP | 60 – 100 HP | 75 – 110 HP |
| Peak Torque | Up to 510 N·m | Up to 430 N·m | Up to 360 N·m | Up to 350 N·m |
| Aspiration Options | Turbo / TI | Turbo / TI | Turbo only | Turbo / TI |
| Global Parts Network | ✅ Extensive | Limited | Limited | Regional |
| Warranty Support | Cummins Global | Regional | Regional | Regional |
The B3.9 offers the highest torque output in its class, backed by Cummins’ global parts and service network — a critical advantage for export equipment and multi-country fleet operations.
Typical Applications
- Excavators — 8–20 ton class machines requiring high breakout torque
- Wheel Loaders — 1–3 m³ bucket capacity loaders for quarry and aggregate work
- Bulldozers — Small to medium dozers for site preparation and grading
- Road Rollers — Compaction equipment for road construction
- Mobile Cranes — Truck-mounted and rough-terrain cranes up to 25 ton capacity
- Concrete Pump Sets — Trailer-mounted and truck-mounted concrete pumps
- Drilling Rigs — DTH and rotary drilling rigs for foundation work
- Engine Power Packs — Standalone power units for custom machinery
Maintenance Cost & Service Intervals
| Maintenance Item | Interval | Estimated Cost (USD) |
|---|---|---|
| Engine Oil & Filter Change | Every 250 hours | $30 – $50 |
| Fuel Filter Replacement | Every 500 hours | $15 – $25 |
| Air Filter Cleaning/Replacement | Every 500 / 1,000 hours | $20 – $40 |
| Valve Lash Adjustment | Every 1,500 hours | $40 – $60 |
| Coolant Replacement | Every 2,000 hours | $25 – $40 |
| Turbocharger Inspection | Every 3,000 hours | $50 – $100 |
| Overhaul (Major) | 10,000 – 12,000 hours | $800 – $1,500 |
Annual maintenance cost for a typical B3.9 running 2,000 hours per year is approximately $300 – $500, significantly lower than comparable Japanese or European engines. Cummins parts are available in over 190 countries, minimizing downtime.
B3.9 Construction vs. B3.9 Generator vs. QSB3.9 Industrial
| Feature | B3.9-C (Construction) | B3.9-G (Generator) | QSB3.9 (Industrial) |
|---|---|---|---|
| Primary Use | Excavators, loaders, dozers | Diesel gensets 30-120 kVA | General industrial equipment |
| Power Unit | HP (80-130) | kW (24-97) | HP (110-130) |
| Governor | Mechanical / Electronic | Electronic (constant speed) | Electronic |
| Torque Focus | High low-RPM torque | Steady-state power | Balanced torque-speed |
| Rated Speed | 1,900 – 2,500 RPM | 1,500 / 1,800 RPM | 2,200 RPM |
Choose B3.9-G if you need a genset engine; choose QSB3.9 for general industrial equipment; choose B3.9-C for mobile construction machinery requiring high torque and rugged durability.
Get Your B3.9 Engine Quote
Tell us your equipment model and power requirement — we’ll match the right B3.9 variant within 12 hours.
Contact BLSH Diesel →Related Cummins Engine Series
Looking for a different power range or application? Explore the full DCEC Cummins family:
- B5.9 Construction — 5.9L, 115-205 HP for larger excavators and loaders
- QSB3.9 Industrial — 3.9L, 110-130 HP for general industrial equipment
- QSB4.5 Industrial — 4.5L, 109-132 HP, Tier 3 emissions
- QSB5.9 Industrial — 5.9L, 130-210 HP for heavy industrial use
- QSB6.7 Industrial — 6.7L, 130-260 HP, the workhorse of the mid-range
- QSC8.3 Industrial — 8.3L, 215-260 HP for heavy-duty applications
- QSL8.9 Industrial — 8.9L, 220-360 HP for the most demanding applications
Official Resources
- Cummins Genuine Parts Catalog — Order OEM parts by engine serial number
Frequently Asked Questions
What is the difference between 4BTAA3.9-C and 4BTA3.9-C?
Both are turbocharged intercooled, but the 4BTAA series uses an air-to-air intercooler (the “AA”), which provides better charge cooling than the water-to-air intercooler on the 4BTA series. This results in higher power density and better performance in hot ambient conditions. For tropical construction sites, the 4BTAA3.9-C is the recommended choice.
Can the B3.9 engine run on biodiesel?
Yes. The B3.9 is compatible with biodiesel blends up to B20 (20% biodiesel) without modification. For higher blends, consult BLSH for compatibility verification. Cummins-approved biodiesel must meet ASTM D6751 or EN 14214 standards.
What is the expected service life of a B3.9 construction engine?
With proper maintenance following the recommended service schedule, the B3.9 achieves 10,000 – 12,000 hours before major overhaul. Many installations in quarry and mining applications exceed 15,000 hours with diligent oil analysis and timely component replacement.
Does BLSH supply spare parts for B3.9 engines?
Yes. We supply complete engine assemblies, replacement short blocks, long blocks, turbochargers, fuel injection pumps, filters and all wear parts. As an authorized channel, we provide genuine Cummins components with full traceability.
What is the minimum order quantity?
For complete engines, MOQ is 1 unit. For spare parts and components, we accommodate flexible quantities. Contact us with your requirements for a detailed quotation including shipping to your destination port.
How does the B3.9 compare to the QSB3.9 for construction use?
The QSB3.9 is optimized for general industrial applications with electronic governance, while the B3.9-C is built specifically for construction with mechanical or electronic governors, higher low-RPM torque, and reinforced components for vibration and dust resistance. For mobile earthmoving equipment, the B3.9-C is the better fit.
