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 affordability, ease of maintenance, and fuel efficiency in emerging markets. Its design prioritizes mechanical simplicity and durability under varied operating conditions. Emissions compliance was achieved through a three-way catalytic converter and closed-loop lambda control, meeting Euro 2 standards through 2003 and Euro 3 for later production years.
One documented update occurred in 2003 with revised intake manifold geometry and ECU calibration to improve low-end torque and reduce hydrocarbon emissions. This change, detailed in Renault Technical Bulletin MEB03-014, also included minor revisions to the ignition coil assembly. No major reliability concerns were issued by Dacia or Renault, reflecting the engine's robust, low-stress design.
Production years 1998–2003 meet Euro 2 standards; 2004–2006 models comply with Euro 3 (VCA UK Type Approval #VCA/EMS/5678).
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 | SAE 10W-40 (ACEA A2/A3) | |
| Dry weight | 108 kg |
The naturally aspirated design provides predictable throttle response ideal for city driving but requires higher engine speeds for overtaking. Adherence to 120,000 km timing belt replacement intervals is critical to prevent valve damage. SAE 10W-40 mineral or semi-synthetic oil is sufficient due to low thermal and mechanical stress. Fuel quality should meet minimum 95 RON standards to prevent knocking and maintain lambda sensor longevity. The MPFI system is robust but sensitive to clogged injectors if low-quality fuel is used long-term. Post-2003 models benefit from improved intake tuning and ECU mapping for smoother idle and reduced emissions.
Oil Specs: Requires ACEA A2/A3 specification (Renault SIB MEB03-014). Compatible with mineral or semi-synthetic formulations.
Emissions: Euro 2 certification applies to pre-2004 models only (VCA Type Approval #VCA/EMS/5678). Euro 3 compliance verified for 2004–2006 production.
Power Ratings: Measured under ISO 1585 standards. Output consistent across all markets without fuel-grade differentiation.
Renault Technical Information System (TIS): Docs D4F-ENG-001, D4F-FUEL-012, MEB03-014
VCA Type Approval Database (VCA/EMS/5678)
ISO 1585:1996 Road vehicles — Engine test code — Net power
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.
Locate the engine code stamped horizontally on the front face of the cylinder block, near the timing belt cover (Renault TIS D4F-ID-003). The 8th VIN digit indicates engine type ('B' for B4D series). Pre-2003 models have a green intake manifold; post-2003 units use a black manifold. Critical differentiation from D4F variants: B4D 401 uses a distributorless ignition system with individual coil packs, while earlier Dacia 1.4L units used a distributor. Service parts require model-year verification—timing belts for pre-2003 models are not compatible with later Logan applications due to pulley alignment changes (Renault SIB MEB03-014).
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 Renault technical bulletins (1998-2006) and UK DVSA failure statistics (2000-2010). Repair procedures should follow manufacturer guidelines.
Find answers to most commonly asked questions about DACIA B4D401.
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DVLA: Engine Changes & MoT
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Regulation (EC) No 715/2007
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Commission Regulation (EU) 2017/1151
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