DCEC Cummins ISDe6.7 Automotive Engine — 185–300 HP Medium-Duty Truck & Bus Power
The DCEC Cummins ISDe6.7 (also branded ISD6.7 in later Euro V/VI catalogs) is a 6.7-liter, inline-six, four-stroke medium-duty diesel engine manufactured by the Dongfeng Cummins Engine Company (DCEC) joint venture. It is the electronically controlled successor to the legendary mechanical B5.9 platform, sharing the same proven bottom-end architecture while adding a Bosch third-generation high-pressure common rail fuel system and full electronic control.
Producing 185 to 300 HP (136–220 kW) with peak torque of 700 to 1,100 N·m, the ISDe6.7 is the best-selling engine in DCEC’s medium-duty lineup. It powers 4×2 and 6×2 cargo trucks, municipal vehicles, fire trucks, intercity buses and school buses across China, Southeast Asia, the Middle East, Africa and Latin America. With a dry weight of just ~500 kg and a compact 940 mm package length, it offers one of the best power-to-weight ratios in the 6–7 liter segment.
Core Specifications
| Parameter | Specification |
|---|---|
| Engine Type | Inline 6-cylinder, 4-stroke, water-cooled, turbocharged & air-to-air intercooled |
| Displacement | 6.7 L (6,700 cc) |
| Bore × Stroke | 107 mm × 124 mm |
| Valve Train | 4 valves per cylinder, 24 valves total, SOHC |
| Rated Power | 136–220 kW (185–300 HP) @ 2,500 RPM (ISDe/ISD); 190–216 kW @ 2,300 RPM (D6.7NS6B) |
| Peak Torque | 700–1,100 N·m @ 1,100–1,800 RPM |
| Rated Speed | 2,500 RPM (Euro III–V); 2,300 RPM (D6.7NS6B Euro VI) |
| Fuel System | Bosch 3rd-generation high-pressure common rail (HPCR), up to 1,600 bar |
| ECM | Continental CM2150E with OBD, UDS/ODX diagnostics |
| Compression Ratio | 17.3 : 1 (ISDe/ISD); 18.5 : 1 (D6.7NS6B) |
| Aspiration | Holset wastegate turbocharger with air-to-air charge air cooling |
| Dry Weight | ~460–509 kg (base engine, varies by configuration) |
| Dimensions (L × W × H) | ~940 × 742 × 837 mm |
| Idle Speed | 700 ± 50 RPM |
| Emissions | Euro III / Euro IV / Euro V / Euro VI (China NS6) |
| Cold Start | −15 °C unaided; −35 °C with intake preheater |
| Best BSFC | ~195 g/kW·h |
| Noise Level | 93 dB(A) at 1 m (rated power) |
| B10 Service Life | ~1,000,000 km |
| Firing Order | 1–5–3–6–2–4 |
Complete Model Lineup
Euro III — ISDe -30 Series (Bosch HPCR)
The Euro III lineup introduced the Bosch common rail system to the D platform in China. These engines use a POC (Particle Oxidation Catalyst) or no aftertreatment depending on market, and remain widely used in Africa, the Middle East and Southeast Asia where lower-sulfur fuel may not be guaranteed.
| Model | Rated Power | Peak Torque | Torque RPM |
|---|---|---|---|
| ISDe210-30A | 155 kW (207 HP) @ 2500 | 800 N·m | @ 1,400 |
| ISDe210-30B | 157 kW (210 HP) @ 2500 | 800 N·m | 1,200–1,700 |
| ISDe230-30 | 169 kW (226 HP) @ 2500 | 900 N·m | @ 1,400 |
| ISDe245-30 | 180 kW (241 HP) @ 2500 | 925 N·m | @ 1,400 |
| ISDe270-30A / -30B | 198 kW (266 HP) @ 2500 | 970 N·m | 1,200–1,700 |
| ISDe285-30 | 210 kW (281 HP) @ 2500 | 970 N·m | 1,200–1,700 |
Euro IV — ISDe -40 Series
Euro IV models use an enhanced Bosch HPCR system with POC/DOC aftertreatment. The lineup extends downward to 185 HP, covering a broader range of medium truck GVW classes. All models are rated at 2,500 RPM with torque peaking at 1,400 RPM.
| Model | Rated Power | Peak Torque | Torque RPM |
|---|---|---|---|
| ISDe185-40 | 136 kW (185 HP) @ 2500 | 700 N·m | @ 1,400 |
| ISDe210-40 | 155 kW (210 HP) @ 2500 | 800 N·m | @ 1,400 |
| ISDe230-40 | 169 kW (230 HP) @ 2500 | 900 N·m | @ 1,400 |
| ISDe245-40 | 180 kW (245 HP) @ 2500 | 950 N·m | @ 1,400 |
| ISDe270-40 | 198 kW (270 HP) @ 2500 | 970 N·m | @ 1,400 |
| ISDe285-40 | 210 kW (285 HP) @ 2500 | 1,020 N·m | @ 1,400 |
Euro V / China V — ISD -50 Series (SCR)
The China V lineup drops the “e” in the model name (ISD rather than ISDe) and adopts SCR aftertreatment. Torque plateaus are widened to 1,200–1,800 RPM on most models, and a new top-end 300 HP variant delivers 1,100 N·m — the highest output ever extracted from the 6.7 L D platform.
| Model | Rated Power | Peak Torque | Torque RPM |
|---|---|---|---|
| ISD190-50 | 144 kW (190 HP) @ 2500 | 700 N·m | 1,100–1,700 |
| ISD210-50 | 155 kW (210 HP) @ 2500 | 800 N·m | 1,200–1,700 |
| ISD230-50 | 169 kW (230 HP) @ 2500 | 900 N·m | 1,200–1,700 |
| ISD245-50 | 180 kW (245 HP) @ 2500 | 950 N·m | 1,200–1,800 |
| ISD270-50 | 198 kW (270 HP) @ 2500 | 970 N·m | 1,200–1,700 |
| ISD285-50 | 210 kW (285 HP) @ 2500 | 1,020 N·m | 1,200–1,800 |
| ISD300-50 | 220 kW (300 HP) @ 2500 | 1,100 N·m | 1,200–1,800 |
Euro VI / China NS6 — D6.7NS6B Series
The latest generation carries the D6.7NS6B designation, rated at a lower 2,300 RPM peak to meet China VI limits with DOC + DPF + SCR aftertreatment. The compression ratio rises to 18.5:1 for cleaner combustion. These are the engines currently fitted to new Dongfeng Tianjin and KR chassis.
| Model | Rated Power | Peak Torque | Turbocharger |
|---|---|---|---|
| D6.7NS6B260 | 190 kW (256 HP) @ 2300 | 1,000 N·m @ 1,100 | HE300WG |
| D6.7NS6B290 | 216 kW (290 HP) @ 2300 | 1,100 N·m @ 1,200 | HE300WG |
Fuel System: Bosch Third-Generation HPCR
The ISDe6.7 uses the Bosch third-generation high-pressure common rail system, operating at injection pressures up to 1,600 bar. Unlike the older mechanical B-series engines that used an in-line injection pump, the ISDe stores fuel at constant high pressure in a common rail and delivers it through electronically controlled solenoid injectors, enabling up to five injection events per cycle (pilot, main, post).
Key benefits of the Bosch HPCR system on the ISDe6.7 include:
- Quieter combustion: Pilot injection pre-heats the combustion chamber, reducing diesel knock by up to 3 dB compared to mechanical B-series engines
- Better low-end response: Full rail pressure is available from 1,100 RPM, delivering 90%+ of peak torque at low engine speeds
- Improved cold start: Pre-injection and precise timing allow reliable starts down to −15 °C unaided
- Lower fuel consumption: The best BSFC of ~195 g/kW·h is roughly 8–10% better than the mechanical B5.9 at equivalent power
- Emissions flexibility: The same base fuel system supports Euro III through Euro VI with changes only to aftertreatment and ECU mapping
Fuel filtration is handled by a Cummins Filtration two-stage system (coarse + fine filter) with water separator. Using fuel that meets the minimum cetane and cleanliness specifications for the emission level is critical — contaminated or high-sulfur fuel can damage the Bosch injectors, which are among the most expensive components on the engine.
Key Engineering Features
Proven D-Platform Bottom End
The ISDe6.7 shares its block architecture with the renowned QSB6.7 industrial engine, using a reinforced cast-iron cylinder block, forged steel crankshaft and fractured-split connecting rods. The mid-stop cylinder liners use platform honing for consistent oil retention and reduced wear. This is not a clean-sheet design — it is the evolution of a platform with decades of field validation in trucks, buses, construction equipment and generator sets worldwide.
Continental CM2150E Electronic Control
The engine is managed by a Continental CM2150E electronic control module with OBD (on-board diagnostics) and UDS/ODX protocol support. The ECM communicates with the vehicle’s AMT transmission, ABS, instrument cluster and body controller over the J1939 data bus. It provides cruise control, PTO management, idle shutdown, engine protection derating and comprehensive fault code logging. The processing capacity is substantially higher than the earlier B-series controllers, enabling more precise fuel mapping and faster response to driver demand.
Holset Wastegate Turbocharger
A Holset (Cummins Turbo Technologies) wastegated turbocharger provides boost across the entire RPM range. The wastegate prevents over-boost at high engine speeds while the turbine housing is sized for quick spool-up at low RPM — a balance that suits the stop-start duty cycles of urban distribution trucks and city buses. The latest D6.7NS6B uses the HE300WG turbo with an electric wastegate actuator for tighter boost control.
NVH Refinement
DCEC engineered the ISDe6.7 for significantly lower noise and vibration than the mechanical B-series. Measures include a double-layer gear chamber cover, viscous (silicone oil) crankshaft damper, isolated valve cover and a structural oil pan. Measured noise at 1 meter under full load is 93 dB(A), meeting China’s GB14097-1999 standard. For bus applications especially, this refinement makes a noticeable difference in passenger cabin comfort.
Cold Start & High-Altitude Performance
With intake air preheating and a high-torque starter, the ISDe6.7 starts reliably at −15 °C without assistance and down to −35 °C with the preheater engaged. The turbocharger and fuel mapping maintain rated power up to approximately 3,000 m altitude with minimal derating, making the engine suitable for high-plateau routes in the Andes, East Africa and Central Asia.
Service Life
DCEC targets a B10 life of 1,000,000 km for the ISDe6.7 under normal medium-truck duty cycles. Approximately 30% of engines reach 800,000 km without a major overhaul. Extended oil drain intervals (up to 40,000 km with CES 20086 approved oil), lifetime valve lash adjustment and auto-tensioning belts all reduce scheduled maintenance time.
Applications
The ISDe6.7 is purpose-built for medium-duty on-highway vehicles. It is not a construction or industrial engine.
| Vehicle Type | Recommended Power | Typical GVW / Class |
|---|---|---|
| 4×2 Cargo / Distribution Truck | 185–245 HP | 12–18 t GVW |
| 6×2 Cargo Truck | 245–285 HP | 18–25 t GVW |
| 4×2 Tractor (regional) | 270–300 HP | 30–35 t GCW |
| Tipper / Dump (medium) | 245–285 HP | 18–25 t GVW |
| Intercity / Tourist Coach (8–10 m) | 210–270 HP | 8–10 m bus |
| City Bus (10–12 m) | 210–285 HP | 10–12 m bus |
| School Bus | 185–245 HP | 8–10 m bus |
| Fire Truck / Municipal Vehicle | 245–300 HP | Specialized chassis |
| Concrete Pump / Specialized | 245–285 HP | Truck-mounted equipment |
ISDe6.7 vs QSB6.7 vs B5.9: Same Displacement Family, Different Missions
The 6.7 L D-platform is one of Cummins’ most versatile engine families, but each version is calibrated for a specific application. Confusing them leads to wrong specifications, warranty problems and unhappy customers.
| Feature | ISDe6.7 Automotive | QSB6.7 Industrial | B5.9 (Mechanical) |
|---|---|---|---|
| Displacement | 6.7 L | 6.7 L | 5.9 L |
| Bore × Stroke | 107 × 124 mm | 107 × 124 mm | 102 × 120 mm |
| Power Range | 185–300 HP @ 2500 RPM | 130–260 HP @ 2200–2500 RPM | 115–210 HP @ 2500 RPM |
| Peak Torque | 700–1,100 N·m | 500–1,000 N·m | 410–880 N·m |
| Fuel System | Bosch HPCR (1,600 bar) | Bosch HPCR / CP3 | Mechanical in-line pump |
| Governor Type | Variable-speed (automotive) | Variable/automotive (industrial) | Mechanical centrifugal |
| Dry Weight | ~500 kg | ~500 kg | ~430 kg |
| Emissions | Euro III–VI | Tier 3 / Stage IIIA | Euro II / unregulated |
| Primary Application | Trucks, buses, municipal | Excavators, loaders, forklifts | Older trucks, construction, pumps |
| Electronics | Full CM2150E ECM + J1939 | CM850/CM2150 ECM | None (mechanical) |
| Fuel Tolerance | Requires low-sulfur diesel | Tier 3 fuel required | Tolerates high-sulfur fuel |
Key takeaway: The ISDe6.7 and QSB6.7 share the same block but are tuned differently — the ISDe has a wider RPM range and automotive torque curve, while the QSB6.7 is governed for industrial PTO duty and often uses a different flywheel housing. The older B5.9 is mechanically controlled and has no electronics, making it preferred in regions with poor fuel quality but lacking the power density, emissions compliance and diagnostic capability of the ISDe6.7.
Competitive Comparison
In the 6–7 liter medium-truck segment, the ISDe6.7 competes primarily with Chinese domestic engines. Here is how it compares:
| Specification | Cummins ISDe6.7 | Weichai WP7 | Yuchai YC6J | FAW Xichai CA6DL |
|---|---|---|---|---|
| Displacement | 6.7 L | 7.5 L | 6.5 L | 6.6 L |
| Cylinders | 6-inline | 6-inline | 6-inline | 6-inline |
| Power Range | 185–300 HP | 240–340 HP | 180–260 HP | 220–310 HP |
| Peak Torque | 700–1,100 N·m | 900–1,250 N·m | 650–950 N·m | 850–1,200 N·m |
| Dry Weight | ~500 kg | ~650 kg | ~580 kg | ~620 kg |
| Rated RPM | 2,500 | 2,300 | 2,500 | 2,300 |
| Fuel System | Bosch HPCR | Bosch/common rail | Bosch/common rail | Denso/common rail |
| Best BSFC | ~195 g/kW·h | ~190 g/kW·h | ~198 g/kW·h | ~193 g/kW·h |
| Service Network | Cummins global (190+ countries) | China + EM | China + SE Asia | China |
The ISDe6.7’s strongest advantages are its lightweight package (roughly 100–150 kg lighter than the Weichai WP7) and the Cummins global service network. For export-focused truck builders and fleet operators whose vehicles cross borders or work in remote regions, the ability to get genuine parts and factory service anywhere in the world is a decisive advantage. The WP7 offers slightly more displacement and torque at the top end but at a significant weight penalty, while the Yuchai YC6J is competitive in the 180–240 HP segment but lacks Cummins’ global parts reach.
Maintenance & Operating Costs
| Service Item | Interval | Notes |
|---|---|---|
| Oil & Filter Change | 20,000–40,000 km | Use Cummins CES 20086 approved 15W-40 / 10W-30 |
| Fuel Filter (coarse + fine) | 20,000 km | Replace both; drain water separator every 10,000 km |
| Valve Lash Inspection | 160,000 km | No scheduled adjustment under normal use |
| Fan Belt | 40,000 km visual / 160,000 km replace | Auto-tensioner; no manual adjustment |
| Coolant Replacement | 2 years / 200,000 km | OAT coolant with DCA4 additive |
| Injector Inspection | No scheduled interval | Monitor via ECM fuel trim; replace on fault code only |
| SCR/DEF System (Euro V/VI) | Per OEM schedule | Use ISO 22241 AdBlue/DEF only |
| Major Overhaul | 800,000–1,000,000 km (B10) | 30% of verified units exceed 800,000 km without overhaul |
For detailed guidance on maintaining Cummins fuel systems, see our Cummins fuel system maintenance and troubleshooting guide. Genuine parts can be verified through the official Cummins Parts portal.
Why Source Your ISDe6.7 from BLSH Diesel?
BLSH Diesel supplies genuine DCEC-manufactured ISDe/ISD6.7 engines and replacement assemblies to truck dealers, fleet operators and importers worldwide. Every engine is factory hot-tested and shipped with full DCEC certification.
- Complete model range: All Euro III, IV, V and China VI (D6.7NS6B) calibrations, including A and B torque variants
- Genuine DCEC product: Direct from Dongfeng Cummins in Xiangyang, China — not rebuilt or aftermarket
- Global shipping: Ocean freight to major ports worldwide; typical lead time 15–30 working days
- Technical support: We help you match the correct SO (Shop Order) number, power curve
