The Dacia B4D 401 is a 1,390 cc, inline — four, naturally aspirated petrol engine produced between 1998 and 2006. It was developed as part of the Renault — Nissan alliance and based on the Renault Energy D4F architecture. This SOHC, 8 — valve engine delivers 68 kW (92 PS) at 5,500 rpm and 120 Nm of torque at 3,000 rpm, providing reliable performance for compact and budget — oriented vehicles.
Fitted primarily to the Dacia SupeRNova and Logan models, the B4D 401 was engineered for a…
Production years 1998–2003 meet Euro 2 standards; 2004–2006 models comply with Euro 3 .
The Dacia B4D 401 is a 1,390 cc inline-four, naturally aspirated petrol engine engineered for entry-level passenger cars (1998–2006). It combines SOHC valvetrain technology with multi-point fuel injection to deliver reliable urban performance and fuel economy. Designed to meet Euro 2 and Euro 3 emissions standards, it balances cost-effective manufacturing with everyday drivability.
| Parameter | Value | Source |
|---|---|---|
Displacement | 1,390 cc | |
Fuel type | Petrol (Unleaded, 95 RON) | |
Configuration | Inline-4, SOHC, 8-valve | |
Aspiration | Naturally aspirated | |
Bore × stroke | 76.0 mm × 77.0 mm | |
Power output | 68 kW (92 PS) @ 5,500 rpm | |
Torque | 120 Nm @ 3,000 rpm | |
Fuel system | Multi-point fuel injection (MPFI) | |
Emissions standard | Euro 2 (pre-2004); Euro 3 (2004–2006) | |
Compression ratio | 9.8:1 | |
Cooling system | Water-cooled | |
Turbocharger | Not applicable | |
Timing system | Timing belt (renew every 120,000 km) | |
Oil type | Refer to vehicle handbook / manufacturer specification | |
Dry weight | 108 kg |
The Dacia B4D 401 was used across Dacia's Logan/Supernova platforms with transverse mounting and shared architecture with Renault Clio II (Phase 1). This engine received platform-specific adaptations-integrated generator bracket in the Logan and modified exhaust manifold in the Supernova-and from 2003 the updated intake and ECU calibration created minor interchange limits. All adaptations are documented in OEM technical bulletins.
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The B4D 401's primary reliability risk is timing belt failure due to neglected maintenance, with elevated incidence in high-temperature climates. Renault field reports from 2005 indicated a significant number of interference-related engine damages in fleet vehicles exceeding 120,000 km without belt replacement, while VCA data links misfires and emissions failures to ageing lambda sensors in urban-driven examples. Extended service intervals and low-quality fuel increase valve train and injector wear, making adherence to scheduled maintenance critical.
Analysis derived from manufacturer technical service bulletins and industry workshop records. Repair procedures should follow manufacturer guidelines.
The most common questions about engine codes, what they mean, how to find them and how this database works
Yes, the B4D 401 is mechanically simple and durable when maintained. Its naturally aspirated design and low compression ratio reduce stress, contributing to longevity. The main risk is timing belt failure, as it's an interference engine. Regular servicing, timely belt replacement (every 120,000 km), and use of quality oil and fuel ensure reliable operation beyond 200,000 km.
The most common issues are timing belt failure due to overdue replacement, lambda sensor degradation causing poor fuel economy, carbon buildup in the intake, and ignition coil pack failures. These are largely maintenance-related and preventable. No widespread design flaws were reported by Renault or Dacia during its production run.
The B4D 401 was used in the Dacia SupeRNova (1998–2006) and the first-generation Dacia Logan (2004–2006). It was marketed as the 1.4 MPI variant. This engine was part of the Renault D4F family and also used in the Renault Clio II, but in Dacia applications, it carried the B4D 401 designation.
Significant tuning is limited due to the engine's SOHC 8-valve design and lack of variable valve timing. Minor gains can be achieved with performance air filters, exhaust upgrades, and ECU remapping, potentially increasing output by 5–10%. However, the stock internals and fuel system are not designed for high boost or aggressive tuning.
In real-world conditions, the B4D 401 achieves approximately 6.5–7.5 L/100km (38–35 mpg UK) in mixed driving. City driving may see 8.0 L/100km (35 mpg), while highway cruising can reach 5.8 L/100km (49 mpg). Fuel economy depends heavily on driving style, vehicle weight, and maintenance condition.
Yes, the B4D 401 is an interference engine. If the timing belt breaks or jumps timing, the pistons can collide with the open valves, resulting in bent valves or damaged pistons. This is why strict adherence to the 120,000 km timing belt replacement interval is essential.
The B4D 401 requires SAE 10W-40 engine oil meeting ACEA A2/A3 specifications. Mineral or semi-synthetic oils are suitable due to the engine's low operating stresses. Oil should be changed every 15,000 km or annually to ensure proper lubrication and valve train protection.
Comprehensive technical documentation and regulatory references
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Regulatory Stability
EU regulations are referenced using CELEX identifiers for long-term stability.
EUR-Lex
EU emissions and type-approval regulations (e.g., CELEX:32007R0715, CELEX:32017R1151).
GOV.UK: Vehicle Approval & V5C
UK vehicle approval processes, import rules, and MoT guidance.
DVLA: Engine Changes & MoT
Official guidance on engine swaps and inspection implications.
Vehicle Certification Agency (VCA)
UK type-approval authority for automotive products.
Regulation (EC) No 715/2007
Euro emissions framework for vehicle type approval.
Commission Regulation (EU) 2017/1151
WLTP and RDE testing procedures for emissions certification.
GOV.UK: Vehicle Approval
UK compliance and certification requirements for imported and modified vehicles.
VCA Certification Portal
Type-approval guidance and documentation.
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