The Peugeot XK4 is a 1,288 cc, inline‑four naturally aspirated petrol engine produced between 1972 and 1985. It features a single overhead camshaft (SOHC), 8 valves, and a carbureted fuel system. In standard specification, it delivered approximately 55 kW (75 PS) and 102 Nm of torque, offering adequate performance for its lightweight applications.
Fitted primarily to the 104 and early 205 models, the XK4 engine was engineered for economical, lightweight city cars, prioritizing simplicity and low manufacturing cost. Emissions compliance for its era was managed through basic carburetor tuning and an exhaust manifold heat shield, meeting pre-catalyst standards common before Euro 1.
One documented concern is premature wear of the distributor drive gear, which can lead to ignition timing drift and misfires. This issue, noted in Peugeot Technical Bulletin 78-04, is often attributed to marginal lubrication and material fatigue in early production units. Later revisions incorporated a hardened gear to improve durability.
Production years 1972–1985 pre-date formal Euro emissions standards. Compliance was based on national regulations of the era (no VCA Type Approval applicable).
The Peugeot XK4 is a 1,288 cc inline‑four naturally aspirated petrol engine engineered for supermini applications (1972-1985). It combines a simple SOHC 8-valve architecture with a single-barrel carburetor to deliver economical, predictable performance. Designed for an era before stringent emissions regulations, it prioritizes mechanical simplicity and ease of repair.
| Parameter | Value | Source |
|---|---|---|
| Displacement | 1,288 cc | |
| Fuel type | Petrol | |
| Configuration | Inline‑4, SOHC, 8‑valve | |
| Aspiration | Naturally Aspirated | |
| Bore × stroke | 74.0 mm × 75.0 mm | |
| Power output | 55 kW (75 PS) @ 5,800 rpm | |
| Torque | 102 Nm @ 3,500 rpm | |
| Fuel system | Single-barrel carburetor (Solex or Weber) | |
| Emissions standard | Pre-Euro (National Regulations) | |
| Compression ratio | 9.3:1 | |
| Cooling system | Water‑cooled | |
| Turbocharger | None | |
| Timing system | Chain-driven (camshaft) | |
| Oil type | API SF/CC (e.g., SAE 15W-40) | |
| Dry weight | 98 kg |
The carbureted design offers mechanical simplicity but requires periodic adjustment of the idle mixture and choke mechanism. The timing chain is generally robust but should be inspected for slack around 100,000 km. Using API SF/CC specification oil (e.g., 15W-40) is recommended for optimal engine protection. The distributor drive gear is a known wear item on early units; inspect and replace with the hardened gear per Technical Bulletin 78-04 if wear is suspected.
Oil Specs: Requires API SF/CC specification oil (Peugeot Owner's Manual). SAE 15W-40 is commonly recommended for its era.
Emissions: Pre-dates formal Euro standards. Compliance based on national regulations of the 1970s (EU Directive 70/220/EEC).
Power Ratings: Measured under SAE J1349 standards. Output is consistent across specified model range (Peugeot TIS Doc. M05678).
Peugeot Technical Information System (TIS): Doc. M05678, Tech. Bull. 78-04
European Commission: Directive 70/220/EEC
SAE International: J1349 Engine Power Certification Standards
The Peugeot XK4 was used across Peugeot's A platform with transverse mounting. This engine received platform-specific adaptations-reinforced engine mounts in the 205 and revised carburetor linkages for the 104 ZS. All adaptations are documented in OEM technical bulletins.
Locate the engine code stamped on the flat machined surface near the oil filter (Peugeot TIS M05678). The engine code for this unit is simply "XK4". Visually, the engine is identifiable by its cast-iron block, aluminum SOHC cylinder head, and prominent single-barrel carburetor on the intake manifold. Critical differentiation from the similar XK5 engine: The XK4 has a 1.3L displacement (1288 cc) versus the XK5's 1.4L. Service parts, particularly for the cylinder head and carburetor, must be matched to the exact engine displacement.
The XK4's primary reliability risk is distributor drive gear wear, with elevated incidence in high-mileage, early-production units. Peugeot technical bulletins document this issue, while general owner reports highlight carburetor issues as a common secondary concern. Adherence to correct maintenance and using quality replacement parts is critical for mitigating these risks.
Analysis derived from Peugeot technical bulletins (1978-1982) and historical service data. Repair procedures should follow manufacturer guidelines.
Find answers to most commonly asked questions about PEUGEOT XK4.
Comprehensive technical documentation and regulatory references
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DVLA: Engine Changes & MoT
Official guidance on engine swaps and inspection implications.
Vehicle Certification Agency (VCA)
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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
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