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 overt…
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 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.
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.
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The J7R 726 can be very reliable long-term if meticulously maintained. Its main weakness is the SOHC valvetrain, prone to wear without strict oil changes. Addressing cooling system components preventatively and keeping the ignition system in top condition are key to longevity. Neglect leads to expensive repairs.
The most frequent issues are camshaft/rocker wear, cooling system leaks (hoses, water pump), carburetor problems on early models, and distributor/ignition failures. These are well-documented in Renault service literature and owner forums for the R25.
The J7R 726 was primarily used in the Renault 25 (various trims like TS, Baccara) from 1984 to 1989. It was not used in other mainstream Renault models like the Alpine V6, which used different J-series variants.
Yes, but significantly increasing power is complex. Modifications include performance carburetors or fuel injection conversions, performance exhausts, and mild camshafts. Major power gains require internal work. Most tuning focuses on improving drivability and throttle response rather than large power increases.
Fuel economy is modest by modern standards. Expect around 10-12 L/100km (24-28 mpg UK) in mixed driving for a Renault 25. Carbureted models are generally less efficient than injected ones. Aggressive driving significantly worsens consumption.
No. The Renault J7R 726 is generally considered a non-interference (or 'free-wheeling') engine. If the timing chain fails, the pistons and valves will not collide, preventing catastrophic internal damage. However, a broken chain will still leave you stranded.
Renault originally specified a quality mineral 15W-40 or 10W-40 engine oil meeting API SF/CC standards. Modern high-quality semi-synthetic or synthetic oils (e.g., 10W-40) compatible with older engines and seals are often recommended for better protection, especially against cam wear.
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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
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