Pump Engine
Cummins 4B3.9 Pump Diesel Engine (30–40 hp)
Cummins 4B3.9 3.9 L 4-cylinder diesel engine, 30–40 hp (24–30 kW), 2 ratings for pump work. Each unit nameplate-verified.
Specifications
- Engine Model
- 4B3.9-P30 ~ P40
- Displacement
- 3.9 L
- Cylinders & Configuration
- Inline 4, 4-cycle
- Rated Power Range
- 24–30 kW (30–40 hp) @ 1500–1800 rpm
- Aspiration
- Naturally Aspirated
- Applications
- Pump
- Documentation
- Nameplate verification + load-test record per serial number
Overview
The Cummins 4B3.9 is a 3.9 L 4-cylinder Cummins diesel engine supplied in 2 factory ratings from 30 hp (24 kW) to 40 hp (30 kW). Every rating listed on this page is a complete engine for pump duty, not a generator set, and each unit ships with its serial number recorded against the specification sheet that applies to it.
Ratings in this family differ in rated speed, peak torque and emissions tier rather than in displacement or cylinder count, so the choice between them is a duty-matching question. The specifications panel and the per-rating entries on this page are generated from the same source data, so a rating quoted here can be matched directly against a delivery document.
Specifications
The specifications panel lists the family-level values that are common to every 4B3.9 rating, including the 3.9 L displacement and the inline 4-cylinder layout. Ratings that share displacement and cylinder count but differ in output are listed individually in the model selection section.
Model Selection: 4B3.9 Ratings
Each entry in this section is one rating of the Cummins 4B3.9. The rated power is the output at the stated speed; the peak torque figure is the value the rating develops at the lower speed shown, which is what normally decides whether a rating suits a given machine. Each rating carries a stable anchor, so a single rating can be linked or quoted directly.
4B3.9-P30
4B3.9-P30 — rated 24 kW (30 hp) at 1500 rpm.
4B3.9-P40
4B3.9-P40 — rated 30 kW (40 hp) at 1800 rpm.
Applications
4B3.9 engines in this family are normally specified for pump work.
Pump duty: ratings in this family are quoted with the pump curve and the driven speed in view, because a pump absorbs power with the cube of speed, so the governing point rather than the nameplate figure decides the match.
Verification, Documentation and Ordering
Each engine is offered with nameplate verification + load-test record per serial number. That means the model and rating printed on the engine nameplate can be checked against the record issued for that serial number before shipment, which is the point most buyers of re-rated or re-exported engines want covered.
To receive a quotation, send the exact rating from the matrix above (for example 4B3.9-P40), the machine or application it will drive, the quantity, and the destination port. If the rating you need is not listed, send the model and the required output and we will confirm whether it belongs to this family or to a neighbouring one.
Buyer tip: Send your 4B3.9 specification, quantity and destination port for a verified quotation and lead time.
Frequently Asked Questions
What is the power range of the 4B3.9?
The 2 ratings listed on this page run from 30 hp (24 kW) to 40 hp (30 kW), at governed speeds between 1500 and 1800 rpm.
What displacement and cylinder count does the 4B3.9 use?
Every rating in this family shares the same 3.9 L displacement and inline 4-cylinder, 4-cycle configuration. Ratings differ in output, rated speed and emissions tier rather than in the base engine.
What is the difference between 4B3.9-P30 and 4B3.9-P40?
4B3.9-P30 is rated 24 kW (30 hp) at 1500 rpm, while 4B3.9-P40 is rated 30 kW (40 hp) at 1800 rpm. They use the same base engine; the higher rating is the one to specify when the driven load needs the extra torque at the lower speed.
How is a 4B3.9 rating ordered?
Send the exact rating shown in the model selection table, the application it will drive, the quantity and the destination port. The engine is then quoted against that rating and confirmed against its nameplate and load-test record.
At what speed is the 4B3.9 rated?
The ratings on this page are governed at 1500 and 1800 rpm. Rated speed fixes the speed the driven machine sees through its gearing, so confirm the governed speed before ordering rather than relying on the power figure alone.
Is the 4B3.9 a complete engine or a generator set?
Every entry on this page is a complete engine. Generator sets and packaged gen-sets are listed separately from this family and are not included here.
