Generator Engines · 4BT3.9
Cummins 4BT3.9 Generator Diesel Engine 36 kW Generator Engine Assembly
Cummins 4BT3.9-G2 4-cylinder in-line diesel engine of 3.9L delivering 36 kW (48 HP) used for prime and standby generator sets.
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Overview
What This Engine Is Built For
Cummins 4BT3.9-G2: a 4-cylinder in-line generator drive diesel engine displacing 3.9L on a 102 * 120 mm bore and stroke, supplied complete by MEP Power. It is rated at 36 kW (48 HP). The engine is turbocharged and water cooled, with a BYC A Pump/RSV Governor fuel system. It is built at the Dongfeng Cummins Plant 4BT3.9-G2. Typical duty is prime and standby generator sets; dry weight with flywheel and alternator is 321 Kg and the overall envelope is 867mm*544mm*988mm.
Model4BT3.9-G2 (36kw)
Rated power36 kW/48HP @ 1500 rpm
Displacement3.9L
AspirationTurbocharged
Net weight321 Kg
Key Benefits
- Delivers 36 kW (48 HP) from 3.9L as a factory-rated assembly.
- Turbocharged induction with water cooling keeps charge temperature under control in continuous duty.
- Dry weight 321 Kg and envelope 867mm*544mm*988mm are published so the installation can be checked before ordering.
- Starts without auxiliary aids down to -12℃.
- Supplied as a complete engine assembly, so the unit goes straight onto the mounts
- Backed by a written warranty of one year or 1000 hours, whichever comes first
Application Scenarios
- Prime mover for a new generator set build
- Standby set engine replacement
- Rental power fleet rebuild
- Containerised power module
Who It Is For
- Genset packagers matching an engine to an alternator
- Rental power companies rebuilding sets between contracts
- Industrial sites replacing the prime mover in an existing canopy
- Telecom and data infrastructure contractors specifying standby power
Problems It Solves
- An engine that does not hold speed under block load makes the whole set unusable.
- Packagers lose weeks when the engine does not match the alternator and the base frame.
- Standby sets sit idle for months and must still start and take load on demand.
- Identifying the right 4BT3.9-G2 variant from a serial number takes experience; MEP Power checks the configuration before quoting.
Technical data
Specification As Published
Values below are the published data for this unit. Where a figure is not listed it was not stated by the source data sheet; ask and we will confirm before you order.
| Model | 4BT3.9-G2 (36kw) |
| Type | 4 Cylinders in Line, 4 Stroke Diesel |
| Displacement | 3.9L |
| Bore x Stroke | 102 * 120 |
| Net Weight | 321 Kg |
| Overall Dimension | 867mm*544mm*988mm |
| Manufacturing Plant | Dongfeng Cummins Plant 4BT3.9-G2 |
| Rated Power/Speed | 36 kW/48HP @ 1500 rpm |
| Standby Power | 40 kW/54HP @ 1500 rpm Torque/ |
| Rated Output | 229 N.m @ 1500 rpm Torque/Standby Output: 255 N.m @ 1500 rpm |
| Low Idle Speed | 950-1050 rpm Fuel Consumption @ Running: ≤ 244g/Kw.h 4BT3.9-G2 |
| Aspiration | Turbocharged |
| Fuel System | BYC A Pump/RSV Governor |
| Governor Type | Mechanical, Regulation ≤5% |
| Electrical System (starter motor/alternator) | 12V/24V |
| Lowest Starting Temp (without auxiliary system) | -12℃ |
| Engine Cooling Fluid Volume | 7.2 L |
| Cooling Method | Water Cooled |
Technical Features
- Cylinders: 4 Cylinders in Line, 4 Stroke Diesel
- Displacement: 3.9L
- Bore and stroke: 102 * 120
- Aspiration: Turbocharged
- Fuel system: BYC A Pump/RSV Governor
- Governor: Mechanical, Regulation ≤5%
- Electrical system: 12V/24V
- Coolant capacity: 7.2 L
Quality Control
- Every engine is inspected by the MEP Power inspection team before it leaves the warehouse
- Engine, configuration and serial numbers are recorded and photographed for the buyer
- Genuine and OEM units are quoted separately so the buyer knows exactly what is supplied
- Warranty on genuine and OEM new engines and generator sets is one year or 1000 hours, whichever comes first; parts and repair labour are covered for quality faults inside that period.
Use and Installation Guide
- Quote the model 4BT3.9-G2 when ordering so the correct variant is supplied.
- Match the flywheel and SAE housing to the alternator before assembly
- Set the governor to the frequency required, 50 Hz or 60 Hz
- Run a load bank test before the set goes into service
- Keep the warranty terms in mind: one year or 1000 hours, whichever comes first.
Customisation Options
- OEM and ODM builds, including your logo and company name on the unit
- Cummins engine customisation and modification to your requirement
- Mining and special explosion-proof builds
- Genuine or OEM parts specified on the quotation
How It Compares
| Compared with | What to consider |
|---|---|
| A rebuilt or used engine of the same rating | A rebuilt unit may show the same 36 kW (48 HP) on paper, but its running history is unknown and the warranty rarely covers the whole engine. |
| A larger engine in the same 4BT3.9 range | Moving up a frame size adds weight, envelope and fuel burn; specify the next size up only if the duty cycle really needs the headroom. |
| A non-Cummins engine of similar output | Parts and service for Cummins families are available in most markets, which matters more over ten years than the purchase price on day one. |
Questions
4BT3.9-G2 Questions
Is this 4BT3.9-G2 a genuine Cummins engine
MEP Power supplies 100% genuine Cummins engines, generator sets and engine parts, plus OEM units and customised builds. Tell us which you need and the quotation will state clearly whether the unit offered is genuine, OEM or a customised build.
What power does the 4BT3.9-G2 produce
The rating supplied is 36 kW (48 HP).
What warranty comes with the engine
New genuine and OEM engines and generator sets carry one year or 1000 hours, whichever comes first. Inside that period MEP Power supplies replacement parts free of charge and covers the cost of the engine repair for quality faults.
How do I confirm this is the right variant for my machine
Send the engine serial number or the nameplate photograph of the unit being replaced. MEP Power checks it against the 4BT3.9-G2 configuration before quoting.
How is the engine shipped and what payment terms apply
Shipment is by sea, air or express depending on size and urgency, arranged by MEP Power or by your own forwarder. Payment terms are Alipay, WeChat, T/T or L/C.
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Quote The 4BT3.9-G2
Send your serial number or nameplate photograph and we will confirm the configuration, then price genuine and OEM options side by side.