Details
Cummins 4BTA3.9-G11 Diesel Generator Engine (70kW / 88kVA)
The Cummins 4BTA3.9-G11 is a 3.9-litre, 4-cylinder inline diesel engine engineered specifically for prime and standby power generation. Manufactured by Dongfeng Cummins Engine Co., Ltd (DCEC), this water-cooled diesel engine delivers a prime power output of 70kW at 1500RPM, making it the industry standard for 88kVA 3-phase 4-wire generator sets.
As a factory-authorised OEM Cummins engine supplier, HekoPower provides the original Cummins 4BTA3.9-G11 engine assembly complete with a 12-month warranty, global shipping, and a standard lead time of approximately 10 business days (Payment terms: T/T, L/C, Western Union).
Tech Specs of Cummins 4BTA3.9-G11 Diesel Generator Engine
General Engine Data
Engine Model: Cummins 4BTA3.9-G11-70kw
Type: 4 Cylinders in Line, 4 Stroke Diesel
Displacement: 3.9 L
Bore * Stroke: 102 * 120
Net Weight: 350 Kg
Overall Dimension: 867mm*544mm*988mm
Key Performance Data
Rated Power/Standby Power(1500 rpm): 70 kW/93 HP, 80 kW/107 HP
Rated Power/Standby Power(1800 rpm): 80 kW/107 HP, 90 kW/120 HP
Rated Speed: 1500/1800 rpm
Low Idle Speed: 950-1050 rpm
Fuel Consumption @ Running: ≤ 244 g/kW.hr
More Technical Data
Aspiration: Turbocharged/Aftercooled
Fuel System: BYC A Pump/GAC Governor
Electrical System (Starter Motor/Alternator): 12V/24V
Lowest Starting Temp Without auxiliary system: -12℃
Cooling Method: Water cooled
Engine Cooling Fluid Volume: 8.3 L
Governor Type: Electronic, Regulation ≤5%
Technical Comparison: 4BTA3.9-G11 vs. 4BT3.9-G2
Procurement teams frequently evaluate the 4BTA3.9-G11 against the smaller 4BT3.9-G2. The defining difference lies in the aspiration and thermal management systems. The "A" in 4BTA indicates the presence of an aftercooler (charge-air cooler).
While the 4BT3.9-G2 is solely turbocharged and capped at 36kW prime power, the aftercooled 4BTA3.9-G11 cools the compressed intake air before it enters the combustion chamber. This denser air-fuel mixture allows the G11 to safely generate 70kW without exceeding safe exhaust gas temperatures (maximum 548°C at standby). Consequently, the Cummins 4BTA3.9-G11 generator engine is strictly required for heavy-duty 88kVA configurations, whereas the G2 is relegated to lighter 45kVA applications.
Real-World Application Scenarios
The rigid cast-iron block and balanced crankshaft of the B-Series make this Cummins G-Drive engine highly adaptable. HekoPower routinely supplies this exact configuration for the following deployments:
Telecom Backup Power: Cell towers require reliable, autonomous starts. The 4BTA3.9-G11 features a 12V or 24V starter motor configuration and an electronic governor that responds to grid failures within milliseconds, maintaining tight frequency control for sensitive radio equipment.
Construction Site Generators: Operating in heavy dust requires robust filtration. The engine tolerates a maximum intake resistance of 6.2 kPa (with a dirty filter element), ensuring continuous power for cranes and welding rigs even before field maintenance can be performed.
Agricultural Irrigation Power: Continuous load demands from high-capacity water pumps test thermal limits. The water-cooled design, paired with an 8.3-litre engine coolant capacity, prevents overheating during continuous 24-hour pumping cycles in ambient temperatures up to 40°C.
Maintenance Schedule and Overhaul Guide
Maximising the lifespan of your Cummins generator diesel engine requires strict adherence to OEM fluid capacities and interval checks.
The lubrication system requires a minimum capacity of 10.9 litres (sump plus filters). Standard oil pressure at idle should read a minimum of 207 kPa, rising to 345 kPa at governed speeds.
Standard Service Intervals:
- 250 Hours: Replace engine oil, oil filter, and fuel water separator. Inspect the tension of the fan drive belt.
- 500 Hours: Replace the primary fuel filter elements. Inspect the turbocharger compressor wheel for foreign object debris.
- 2,000 Hours (Overhaul Check): Check valve lash clearance. The intake valves require adjustment to 0.25mm, and exhaust valves to 0.50mm. Clean the aftercooler core to maintain intake air density.
When sourcing components from a Cummins parts catalog, always verify you are purchasing genuine parts. Inferior aftermarket fuel injectors often fail to maintain the 30 litre/hour maximum return flow rate, causing rough idling and wet-stacking at low loads.
Common Misconceptions Regarding the 4BTA3.9-G11
Misconception 1: Any alternator will fit.
While the SAE3 flywheel housing is standard, Cummins 4BTA3.9-G11 alternator compatibility depends on the mass moment of inertia. The engine's rotating components have an inertia of 0.143 kg·m². Ensure your selected alternator (e.g., Stamford UCI224G or Leroy Somer) matches this spec to avoid torsional vibration failures in the coupling disc.
Misconception 2: "DCEC" means aftermarket.
Many buyers assume only Cummins USA manufactures original equipment. DCEC (Dongfeng Cummins Engine Co., Ltd) is a 50/50 joint venture established by Cummins Inc. A DCEC engine is a genuine, original Cummins generator engine built to exact global factory tolerances, fully supported by the international warranty network.
Cummins B3.9-G Series, original products from Dongfeng Cummins Engine Plant (DCEC), Cummins Joint Venture Plant since 1986, 50% shareholding by Cummins USA. This series mainly includes 4B3.9-G1-24kw, 4B3.9-G2-24kw, 4BT3.9-G1-36kw, 4BT3.9-G2-36kw, 4BTA3.9-G2-50kw, 4BTA3.9-G2-58kw, 4BTA3.9-G11-70kw.In accordance with the criteria of Machinery Safety Directive 2006/42, movable elements such as distribution belts, fans, and parts that acquire high temperatures during operation, such as exhaust manifolds, have their respective safeguards. Before being delivered, the generator is thoroughly checked at the factory. Voltage, frequency, and load are all tested, as well as the appropriate operation of warnings and the influence of engine oil temperature on stop.
Frequently Asked Questions
What is the original genuine Cummins 4BTA3.9-G11 engine price?
Pricing fluctuates based on global steel costs and specific accessory configurations (e.g., radiator type, 12V vs 24V starting system). As a direct China Cummins 4BTA3.9-G11 supplier, HekoPower bypasses middleman markups. Contact our sales engineering team at sales@hekopower.com for a current FOB wholesale quote.
Can this engine run continuously at 80kW?
No. 80kW is the standby rating, designed strictly for emergency use during grid outages for a maximum of 1 hour per 12 hours of operation. For continuous 24/7 operation without grid backup, the load must not exceed the prime power rating of 70kW.
Does HekoPower export the complete engine assembly?
Yes. We are a licensed Cummins 70kW diesel engine exporter. The engine assembly is shipped on a fortified steel skid, fully shrink-wrapped, and coated in an anti-corrosion layer suitable for extended ocean freight. All export documentation, including origin certificates, is handled in-house.
