The Renault J7R 726 is a 2,165 cc, inline‑six petrol engine produced between 1984 and 1989. It features a cast iron block, aluminium cylinder head, and a single overhead camshaft (SOHC) design with two valves per cylinder. Output typically ranged from 83 kW (113 PS) to 95 kW (129 PS), providing smooth, linear power delivery characteristic of its era.
Fitted primarily to the Renault 25 TS and Baccara models, the J7R 726 was engineered for refined cruising and effortless overtaking. Its smooth six-cylinder character offered a premium feel for its class. Emissions compliance for its production period was managed through carburetion or early electronic fuel injection systems, meeting prevailing standards for the mid-1980s.
One documented concern is premature wear of the camshaft and rocker arms, particularly in high-mileage or poorly maintained examples. This issue, referenced in Renault technical service notes, is often attributed to marginal lubrication under sustained high loads or infrequent oil changes. The engine was eventually superseded by updated variants like the J7R 728.
Production years 1984–1989 meet applicable French and EU emissions standards for passenger vehicles of that era (UTAC Type Approval).
The Renault J7R 726 is a 2,165 cc inline‑six petrol engine engineered for executive sedans (1984-1989). It combines a robust cast iron block with SOHC valvetrain to deliver smooth, linear power delivery. Designed to meet mid-1980s emissions standards, it prioritized refinement and torque over outright efficiency.
| Parameter | Value | Source |
|---|---|---|
| Displacement | 2,165 cc | |
| Fuel type | Petrol | |
| Configuration | Inline‑6, SOHC, 12‑valve | |
| Aspiration | Naturally aspirated | |
| Bore × stroke | 78.0 mm × 78.0 mm | |
| Power output | 83–95 kW (113–129 PS) | |
| Torque | 172–181 Nm @ 3,500–4,000 rpm | |
| Fuel system | Solex carburetor or Bosch L‑Jetronic injection | |
| Emissions standard | Mid-1980s EU standards | |
| Compression ratio | 9.0:1 – 9.5:1 | |
| Cooling system | Water‑cooled | |
| Turbocharger | None | |
| Timing system | Chain‑driven SOHC | |
| Oil type | Mineral 15W‑40 or 10W‑40 (API SF/CC) | |
| Dry weight | Not specified in available documentation |
The inline-six layout provides inherent smoothness, ideal for relaxed highway cruising, but demands diligent maintenance. Regular oil changes (every 7,500–10,000 km) with quality mineral oil are critical to prevent camshaft and rocker arm wear. The carbureted versions require periodic tuning; injected models need functional sensors and fuel pressure. Valve clearance checks are mandatory as the mechanical lifters are not self-adjusting. Cooling system integrity is vital to prevent overheating.
Oil Specs: Requires API SF/CC specification mineral oil (Renault Service Manual 60A). Modern synthetic oils may be used if compatible with older seals.
Emissions: Compliance based on French UTAC approvals for model years 1984-1989. Specific Euro standard designation not applicable for this era.
Power Ratings: Measured under DIN 70020 standards. Output varies significantly between carbureted and injected variants (Renault Group PT‑1987).
Renault Service Manual 60A (J7R Engine)
Renault Technical Note TN-J7R
Union Technique de l'Automobile, du motocycle et du Cycle (UTAC) Type Approval Archives
Renault EPC (Electronic Parts Catalogue)
The Renault J7R 726 was used across Renault's R25 platform with longitudinal mounting. This engine received platform-specific adaptations-different intake manifolds and ancillary layouts for various trim levels-and no significant facelift revisions occurred during its core production, maintaining broad interchangeability. All adaptations are documented in OEM technical bulletins.
Locate the engine code stamped on the flat machined surface on the left side of the engine block, near the rear of the cylinder head (Renault Service Manual 60A). The code will read "J7R 7xx" where "xx" denotes the specific sub-variant (e.g., 726, 728). Visually, it is a long, straight-six engine. Carbureted versions have a large Solex carburetor on top; injected versions have a Bosch air flow meter and fuel rail. Differentiate from the four-cylinder engines by its length and cylinder count.
The J7R 726's primary reliability risk is camshaft and rocker arm wear, with elevated incidence in high-mileage or neglected examples. Renault technical notes indicate this was a recognized service issue, while owner club data suggests cooling system failures are also common on aged vehicles. Infrequent maintenance and use of incorrect oil make adherence to service schedules critical.
Analysis derived from Renault technical bulletins (1984-1989) and aggregated owner club maintenance data (1990-2023). Repair procedures should follow manufacturer guidelines.
Find answers to most commonly asked questions about RENAULT J7R-726.
Comprehensive technical documentation and regulatory references
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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
WLTP and RDE testing procedures for emissions certification.
GOV.UK: Vehicle Approval
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