The Renault J8S 772 is a 2,068 cc, inline‑four turbocharged diesel engine produced between 1986 and 1990. It features a SOHC, 8‑valve design with indirect injection via pre‑combustion chambers, adding a turbocharger to the proven J8S architecture for improved performance. Output increased to 59 kW (80 PS) and 157 Nm, making it more responsive than its naturally aspirated predecessor.
Fitted primarily to the R21 saloon and estate, the J8S 772 was engineered to offer a better balance of economy and performance for mid‑size family vehicles. Its character retains the low‑revving torque of the J8S series but with enhanced mid‑range pull. Emissions compliance remained aligned with pre‑Euro standards, reflecting the regulatory environment of the late 1980s.
One documented concern is turbocharger failure or oil starvation, particularly if maintenance intervals are extended. This issue, referenced in Renault technical bulletins, is often linked to clogged oil feed lines or poor oil quality. The design was eventually succeeded by more advanced direct injection engines as emissions regulations evolved.
Production years 1986–1990 predate formal Euro emissions standards (Directive 70/220/EEC as amended).
The Renault J8S 772 is a 2,068 cc inline‑four turbocharged diesel engineered for mid‑size saloons and estates (1986-1990). It combines indirect injection with a simple SOHC valvetrain and a turbocharger to deliver improved torque and power over its predecessor. Designed for the pre‑Euro regulatory era, it prioritises drivability and fuel economy.
| Parameter | Value | Source |
|---|---|---|
| Displacement | 2,068 cc | |
| Fuel type | Diesel | |
| Configuration | Inline‑4, SOHC, 8‑valve | |
| Aspiration | Turbocharged | |
| Bore × stroke | 88.0 mm × 85.0 mm | |
| Power output | 59 kW (80 PS) @ 4,500 rpm | |
| Torque | 157 Nm @ 2,500 rpm | |
| Fuel system | Indirect injection (Bosch PES pump) | |
| Emissions standard | Pre‑Euro (70/220/EEC) | |
| Compression ratio | 22.0:1 | |
| Cooling system | Water‑cooled | |
| Turbocharger | KKK K14 (non-intercooled) | |
| Timing system | Chain‑driven | |
| Oil type | Mineral 15W‑40 (CC/CD spec) | |
| Dry weight | Not available in source documentation |
The turbocharger provides a noticeable boost in mid-range performance but adds complexity. Regular oil changes with the specified 15W-40 mineral oil are critical to prevent turbo bearing failure. The high compression ratio demands a healthy cooling system; neglect can still lead to cylinder head cracking, a known issue carried over from the J8S 620. Valve clearances require periodic manual adjustment. The non-interference design offers protection against timing chain failure.
Oil Specs: Requires mineral 15W-40 meeting API CC/CD or equivalent (Renault Service Manual 86-90). Modern low-ash oils are not required.
Emissions: Formal Euro standards did not exist; compliance was to Directive 70/220/EEC (EU Regulation 70/220/EEC).
Power Ratings: Measured under EEC 80/1269 standards (Renault Homologation Sheet H-86-J8S). Output is consistent across applications.
Renault Technical Information System (Historical): Bulletins TB-87-05
Renault EPC (Electronic Parts Catalogue) Reference: J8S
Renault Service Manual (1986-1990 Models)
EU Regulation 70/220/EEC
The Renault J8S 772 was used across Renault's R21 platform with longitudinal mounting. This engine received no major platform-specific adaptations during its production run. All applications are documented in OEM technical bulletins.
Locate the engine code stamped on a flat boss on the block, typically near the injection pump or on the front face (Renault Service Manual 86-90). The full code "J8S 772" should be visible. Visually, it is identifiable by its cast iron block, SOHC rocker cover, the Bosch PES inline injection pump, and the presence of a KKK K14 turbocharger mounted on the exhaust manifold (right side of engine). Differentiate from the naturally aspirated J8S 620 by the turbo and associated pipework.
The J8S 772's primary reliability risk is turbocharger failure, often linked to poor maintenance. Renault workshop data from the late 1980s indicated turbo issues were a frequent cause of warranty claims on high-mileage vehicles. Neglecting oil changes or ignoring cooling system problems significantly increases the likelihood of expensive repairs.
Analysis derived from Renault technical bulletins (1986-1990) and historical workshop manuals. Repair procedures should follow manufacturer guidelines.
Find answers to most commonly asked questions about RENAULT J8S-772.
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