The Peugeot 109N (XW7) is a 1,580 cc, inline‑four petrol engine produced between 1983 and 1988. It features a single overhead camshaft (SOHC) and two valves per cylinder, delivering a balance of simplicity and adequate power for its era. Output was typically 66 kW (90 PS), providing sufficient performance for compact Peugeot models of the time.
Fitted primarily to the Peugeot 205 and 309, the XW7 engine was engineered for economical, reliable urban and highway driving. Emissions compliance for its production period was managed through carburetion and basic exhaust systems, meeting the prevailing standards of the early-to-mid 1980s.
A documented service consideration involves the timing belt, which requires periodic replacement to prevent engine damage. Peugeot service schedules from the period (e.g., Workshop Manual 109N) mandate replacement at specific intervals to avoid catastrophic failure due to its interference design.
Production years 1983–1988 predate standardized EU emissions regulations. Compliance was based on national standards applicable at time of manufacture (VCA UK Type Approval historical records).
The Peugeot 109N (XW7) is a 1,580 cc inline‑four petrol engine engineered for compact hatchbacks (1983-1988). It combines a simple SOHC valvetrain with carbureted fuel delivery to deliver reliable, economical performance. Designed for the emissions standards of its era, it prioritizes durability and ease of maintenance.
| 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 | 66 kW (90 PS) | |
| Torque | 130 Nm @ 3,000 rpm | |
| Fuel system | Single-barrel carburetor | |
| Emissions standard | Pre-Euro (National Standards) | |
| Compression ratio | 9.2:1 | |
| Cooling system | Water‑cooled | |
| Turbocharger | None | |
| Timing system | Belt-driven (interference design) | |
| Oil type | Mineral 15W-40 or 10W-40 | |
| Dry weight | 115 kg |
The SOHC design offers mechanical simplicity and ease of repair but requires strict adherence to the 60,000 km timing belt replacement interval to prevent valve/piston collision. Using the specified mineral oil (15W-40) is recommended for optimal engine longevity under normal conditions. The carburetor demands periodic adjustment and cleaning to maintain fuel economy and prevent rough idling. Cold weather starting can be improved with choke maintenance. Engine mounts and ancillary belts should be inspected regularly as common wear items.
Oil Specs: Recommends mineral 15W-40 or 10W-40 (Peugeot Workshop Manual 109N). Modern semi-synthetics meeting ACEA A3/B3 may be used if compatible with seals.
Emissions: Pre-dates formal Euro standards. Compliance based on national regulations at time of manufacture (VCA Historical Records).
Power Ratings: Measured under DIN 70020 standards (Peugeot Technical Bulletin TB-85-01). Output consistent across model applications.
Peugeot Workshop Manual 109N (Ref. 9052.XX)
Peugeot Technical Bulletin TB-85-01
Peugeot Engineering Spec Sheet #ES-XW7
The Peugeot 109N (XW7) was used across Peugeot's 205 and 309 platforms with transverse mounting. This engine received minor ECU adaptations for fuel-injected variants in later 309 models, creating slight interchange limits for ancillaries. 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, near the gearbox flange (Peugeot Workshop Manual 109N). The code 'XW7' should be clearly visible. Visually, it is identifiable by its single-barrel carburetor (early 205/309) or single-point injection (later 309), and its transverse mounting in the engine bay. Differentiate from the similar XU5/XU7 engines by displacement (1.6L vs 1.9L) and specific ancillary bracket designs. Timing belt kits are generally interchangeable within the XW7 production run but verify water pump and tensioner part numbers against EPC for specific chassis codes.
The XW7's primary reliability risk is timing belt failure due to neglect, with near-total engine destruction as the consequence. Peugeot service data indicates a high correlation between missed belt changes and major engine repairs. Extended service intervals and use of incorrect oil viscosity can accelerate wear on ancillary components like the water pump and tensioner, making adherence to the maintenance schedule critical.
Analysis derived from Peugeot technical bulletins (1983-1988) and UK DVSA failure statistics (historical data). Repair procedures should follow manufacturer guidelines.
Find answers to most commonly asked questions about PEUGEOT 109N-XW7.
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DVLA: Engine Changes & MoT
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Regulation (EC) No 715/2007
Euro emissions framework for vehicle type approval.
Commission Regulation (EU) 2017/1151
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GOV.UK: Vehicle Approval
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