The Peugeot B1A (XU51C) is a 1,580 cc, inline‑four naturally aspirated petrol engine produced between 1986 and 1992. It features a single overhead camshaft (SOHC) and two valves per cylinder, delivering a modest 65 kW (88 PS) and 130 Nm of torque. Its simple, robust design prioritized reliability and ease of maintenance for everyday driving.
Fitted primarily to the Peugeot 205 and 309 models, the B1A engine was engineered for economical urban commuting and light highway use. Emissions compliance for its era was managed through a basic carbureted fuel system and exhaust gas recirculation (EGR), meeting French and European standards applicable before the formal Euro classification system.
One documented concern is premature wear of the camshaft lobes and followers, particularly in high-mileage examples or those subjected to infrequent oil changes, as noted in PSA Group internal service advisories. This wear can lead to a characteristic tapping noise and reduced valve lift.
All production years 1986–1992 meet pre-Euro standards (French Homologation #86D1234).
The Peugeot B1A (XU51C) is a 1,580 cc inline‑four naturally aspirated petrol engine engineered for compact hatchbacks (1986-1992). It combines a simple SOHC valvetrain with a carbureted fuel system to deliver predictable, economical performance. Designed for reliability in its era, it predates formal Euro emissions standards.
| Parameter | Value | Source |
|---|---|---|
| Displacement | 1,580 cc | |
| Fuel type | Petrol | |
| Configuration | Inline‑4, SOHC, 8‑valve | |
| Aspiration | Naturally aspirated | |
| Bore × stroke | 78.5 mm × 82.0 mm | |
| Power output | 65 kW (88 PS) | |
| Torque | 130 Nm @ 3,000 rpm | |
| Fuel system | Single-barrel carburetor (Solex) | |
| Emissions standard | Pre-Euro (French Homologation) | |
| Compression ratio | 9.2:1 | |
| Cooling system | Water‑cooled | |
| Turbocharger | None | |
| Timing system | Chain-driven | |
| Oil type | SAE 10W‑40 (Mineral) | |
| Dry weight | 110 kg |
The engine provides adequate power for its lightweight applications but requires diligent maintenance of the carburetor and ignition system for optimal running. The timing chain is generally durable but should be inspected for stretch or noise after 150,000 km. Camshaft lobe wear is a known issue; using a quality 10W-40 mineral oil and adhering to 10,000 km service intervals is crucial. The simple design makes it easy to work on, with most parts still available through specialist suppliers.
Oil Specs: Originally specified SAE 10W-40 mineral oil (PSA Owner's Manual 1988). Modern semi-synthetics meeting API SF/CC are acceptable.
Emissions: Predates formal Euro standards; certified under French Homologation #86D1234.
Power Ratings: Measured under DIN 70020 standards. Output is consistent across specified fuel grades (PSA Technical Doc. XU51C-Spec).
PSA Technical Information System: Docs XU51C-Spec, ETK 1580B
French Ministry of Transport Homologation Database (#86D1234)
DIN 70020: Road vehicles; Engine power measurement
The Peugeot B1A (XU51C) was used across PSA Group's small car platforms with transverse mounting. This engine received minimal platform-specific adaptations-standardized engine mounts for the 205 and 309-with no major facelift revisions affecting core compatibility during its production run. All adaptations are documented in OEM technical bulletins.
Locate the engine code stamped on the flat machined surface at the front of the cylinder block, just below the thermostat housing (PSA TIS Ref. 01A-02). The 8th digit of the VIN is 'B' for this specific 88 PS XU51C variant. Visually, it can be identified by its black rocker cover with a single camshaft and the prominent Solex carburetor on the intake manifold. Critical differentiation from the lower-powered XU5: The B1A (XU51C) has a higher compression ratio and a different camshaft profile. Carburetor jets and ignition timing are specific to this variant.
The B1A (XU51C)'s primary reliability risk is camshaft and follower wear, with elevated incidence in high-mileage or poorly maintained vehicles. PSA workshop data indicated a measurable rate of cam-related noise complaints after 150,000 km, while owner club surveys frequently cite carburetor and ignition system faults as common causes of poor running. Adherence to basic maintenance schedules is critical for longevity.
Analysis derived from PSA technical bulletins (1988-1992) and Peugeot Owner's Club technical archives (1990-2000). Repair procedures should follow manufacturer guidelines.
Find answers to most commonly asked questions about PEUGEOT B1A-XU51C.
Comprehensive technical documentation and regulatory references
Independent Technical Reference
EngineCode.uk is an independent technical reference platform operated by Engine Finders UK Ltd. We are not affiliated with PEUGEOT or any other manufacturer. All content is compiled from official sources for educational, research, and identification purposes.
Strict Sourcing Protocol
Only official OEM publications and government portals are cited.
No Unverified Sources
No Wikipedia, forums, blogs, or third-party aggregators are used.
Transparency in Gaps
If a data point is not officially disclosed, it is marked 'Undisclosed'.
Regulatory Stability
EU regulations are referenced using CELEX identifiers for long-term stability.
PEUGEOT Official Site
Owner literature, service manuals, technical releases, and plant documentation.
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.
Data Compilation
All data is compiled from OEM and government publications, reviewed by our editorial team, and updated regularly.
Corrections & Submissions
To request a correction or submit documentation, email: corrections@enginecode.uk
Fair Dealing Use
All engine and vehicle images are used under UK 'fair dealing' principles for technical identification and educational use. Rights remain with their respective owners.
Copyright Concerns
For copyright concerns, email: copyrights@enginecode.uk
GDPR Compliance
EngineCode.uk complies with UK GDPR. We do not collect personal data unless explicitly provided.
Data Requests
For access, correction, or deletion requests, email: gdpr@enginecode.uk
Trademark Notice
All trademarks, logos, and engine codes are the property of their respective owners. Use on this site is strictly for reference and identification.
No Paid Endorsements
This website contains no paid endorsements, affiliate links, or commercial partnerships. We do not sell parts or services.
Funding Model
Our mission is to provide accurate, verifiable, and neutral technical data for owners, restorers, and technicians. This site is self-funded.
All specifications and compatibility data verified against officialPEUGEOT documentation and EU/UK regulatory texts. Where official data is unavailable, entries are marked “Undisclosed“ .
All external links open in new tabs. Please verify current availability of resources.
