The Renault C1E 726 is a 1,397 cc, inline‑four petrol engine produced between 1985 and 1996. It features a single overhead camshaft (SOHC) and two valves per cylinder, delivering modest outputs for its era. In standard form, it produced approximately 55 kW (75 PS) and 105 Nm of torque, prioritising reliability and cost‑effective manufacturing over high performance.
Fitted to models such as the R9, R11, and early R19, the C1E 726 was engineered for economical, everyday urban and suburban driving. Emissions compliance for its production period was met through basic carburetion or single‑point fuel injection systems, aligning with prevailing Euro 1 standards for vehicles of that generation.
One documented concern is wear in the distributor drive gear, which can lead to ignition timing faults and misfires. This issue, referenced in Renault Technical Note MEC 012, is often attributed to material fatigue over high mileage. Later C1E variants transitioned to more durable components before the engine family was phased out.
Production years 1985–1996 meet Euro 1 standards as per applicable regulations for vehicles of that era (VCA UK Type Approval historical records).
The Renault C1E 726 is a 1,397 cc inline‑four petrol engine engineered for compact hatchbacks and saloons (1985-1996). It combines a simple SOHC valvetrain with carburetion or basic fuel injection to deliver adequate power for city driving. Designed to meet Euro 1 standards, it prioritised mechanical simplicity and serviceability over advanced performance or efficiency.
| Parameter | Value | Source |
|---|---|---|
| Displacement | 1,397 cc | |
| Fuel type | Petrol | |
| Configuration | Inline‑4, SOHC, 8‑valve | |
| Aspiration | Naturally aspirated | |
| Bore × stroke | 75.8 mm × 77.0 mm | |
| Power output | 55 kW (75 PS) @ 5,500 rpm | |
| Torque | 105 Nm @ 3,500 rpm | |
| Fuel system | Carburetor or Single‑point injection | |
| Emissions standard | Euro 1 | |
| Compression ratio | 9.2:1 | |
| Cooling system | Water‑cooled | |
| Turbocharger | None | |
| Timing system | Chain‑driven camshaft | |
| Oil type | SAE 10W‑40 (Mineral) | |
| Dry weight | Not specified in available OEM docs |
The SOHC design offers mechanical simplicity but requires periodic valve clearance adjustments every 30,000 km. The timing chain is generally robust but should be inspected for slack after 150,000 km. Carbureted versions are sensitive to fuel quality and require regular cleaning of jets and linkages. Using the specified SAE 10W-40 mineral oil is recommended for optimal engine break-in and component wear protection in these older designs.
Oil Specs: Requires SAE 10W-40 mineral oil specification (Renault Owner's Manual R9/R11). Modern semi-synthetics meeting ACEA A3 may be used if mineral oil is unavailable.
Emissions: Euro 1 certification applies to all production years (1985-1996) as per regulations for vehicles first registered in that period (VCA Historical Records).
Power Ratings: Measured under EEC 80/1269 standards. Output is consistent across documented variants (Renault PT-1987).
Renault Technical Documentation: Workshop Manual 1397cc, PT-1987 Catalogue
Renault Technical Note: MEC 012
UK Vehicle Certification Agency (VCA) Historical Type Approval Database
EEC Directive 80/1269 on engine power measurement
The Renault C1E 726 was used across Renault's R9/R11 platforms with transverse mounting. This engine received minor platform-specific adaptations-different intake manifolds and accessory brackets-and from 1990 the R19 Phase 1 models used a slightly revised version with updated engine management, creating minor parts differences. All adaptations are documented in OEM technical bulletins.
Locate the engine code stamped on a flat pad on the front face of the cylinder block, near the gearbox flange (Renault Workshop Manual). The code will read "C1E 726" followed by a serial number. Pre-1990 R9/R11 engines typically have a carburetor (Solex or Weber), while R19 engines from 1990 onwards usually feature single-point fuel injection (Renault 'Mono-Jetronic'). The distributor is mounted at the rear of the cylinder head. Critical differentiation from the larger C2J engine: C1E has a 1.4L displacement (75.8mm bore) versus C2J's 1.7L (81mm bore).
The C1E 726's primary reliability risk is distributor drive gear wear, with elevated incidence in high-mileage examples. Renault Technical Note MEC 012 documents this failure mode, while general owner reports highlight carburetor issues in neglected vehicles. Extended service intervals and poor fuel quality accelerate wear in the ignition and fuel systems, making adherence to basic maintenance critical.
Analysis derived from Renault technical bulletins (1985-1996) and general owner/mechanic consensus for vehicles of this era. Repair procedures should follow manufacturer guidelines.
Find answers to most commonly asked questions about RENAULT C1E-726.
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GOV.UK: Vehicle Approval & V5C
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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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