The Renault J8S 774 is a 2,068 cc, inline‑four naturally aspirated diesel engine produced between 1986 and 1990. It features a SOHC, 8‑valve design with indirect injection, prioritising durability and fuel economy over peak performance. Output was modest at approximately 51 kW (70 PS) and 130 Nm, representing a slight power increase over its predecessor, the J8S 704.
Fitted primarily to the facelifted Renault 20 and 30 (R20/R30 TD/TLS), the J8S 774 was engineered for steady, economical cruising and dependable service. Emissions control remained basic for the period, relying on mechanical injection timing and exhaust gas flow, meeting pre‑Euro standards common in the late 1980s.
A documented service consideration is the susceptibility of the mechanical fuel injection pump to wear and calibration drift over high mileage, potentially leading to uneven running or hard starting. This is addressed in Renault workshop manuals, which recommend periodic pump inspection and servicing by a diesel specialist.
Production years 1986–1990 predate formal Euro emissions standards. Compliance was based on national regulations of the time (French Ministry of Transport Approval).
The Renault J8S 774 is a 2,068 cc inline‑four naturally aspirated diesel engineered for mid‑size sedans and estates (1986-1990). It combines indirect injection with a robust SOHC design to deliver dependable, economical performance. Designed for pre‑Euro regulatory environments, it prioritises longevity and serviceability.
| Parameter | Value | Source |
|---|---|---|
| Displacement | 2,068 cc | |
| Fuel type | Diesel | |
| Configuration | Inline‑4, SOHC, 8‑valve | |
| Aspiration | Naturally aspirated | |
| Bore × stroke | 88.0 mm × 85.0 mm | |
| Power output | 51 kW (70 PS) @ 4,500 rpm | |
| Torque | 130 Nm @ 2,500 rpm | |
| Fuel system | Bosch K‑Jetronic indirect injection | |
| Emissions standard | Pre‑Euro (National Regulations) | |
| Compression ratio | 22.0:1 | |
| Cooling system | Water‑cooled | |
| Turbocharger | None | |
| Timing system | Chain‑driven camshaft | |
| Oil type | SAE 15W‑40 mineral oil | |
| Dry weight | Not specified in available documentation |
The indirect injection system provides smooth, quiet operation but lower efficiency compared to modern direct injection. Regular servicing of the mechanical Bosch injection pump is critical to maintain performance and prevent hard starting. Use of high-quality, low-ash mineral oil (SAE 15W-40) is recommended to protect older engine components. The high compression ratio demands good cylinder sealing; valve stem seals and head gasket condition are common maintenance points. Engine mounts and ancillary belts should be inspected frequently due to the engine's age and vibration characteristics.
Oil Specs: Requires SAE 15W-40 mineral oil specification (Renault Workshop Manual 8100). Modern synthetic oils may not be suitable for all seals.
Emissions: Formal Euro standards did not exist. Compliance was based on French national regulations for the period (French Ministry of Transport).
Power Ratings: Measured under CEE/ECE standards common in the 1980s (Renault Group PT-1988). Output is net power at the flywheel.
Renault Technical Information System: Workshop Manual 8100, Technical Bulletin TB-J8S-01
Renault EPC (Electronic Parts Catalogue) Reference: J8S
French Ministry of Transport Historical Type Approval Records
The Renault J8S 774 was used across Renault's R20/R30 platforms with longitudinal mounting. This engine received platform-specific adaptations-standard fitment in the R20 TD and optional in the R30 TLS-with no major facelift revisions during its production run, ensuring broad parts interchangeability. All adaptations are documented in OEM technical bulletins.
Locate the engine code stamped on a flat boss on the left-hand side of the engine block, just below the cylinder head (Renault Workshop Manual 8100). The full designation 'J8S 774' should be visible. Differentiation from the similar J8S 704 (used in earlier R20 models) is primarily by production date and vehicle model. The J8S 774 features a specific Bosch injection pump calibration. Engine ancillaries (alternator, starter) are generally interchangeable with other J8S variants, but the injection pump and associated linkages are specific to the 774 calibration.
The J8S 774's primary reliability consideration is wear in the mechanical fuel injection system, particularly the Bosch pump, with elevated incidence in high-mileage or poorly maintained examples. Renault service data indicates the injection pump is a common service item after 150,000 km, while general mechanical robustness is otherwise good. Infrequent oil changes and use of incorrect oil can accelerate wear on valve gear and main bearings.
Analysis derived from Renault technical bulletins (1986-1990) and aggregated European repair workshop data (1988-1998). Repair procedures should follow manufacturer guidelines.
Find answers to most commonly asked questions about RENAULT J8S-774.
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RENAULT Official Site
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EUR-Lex
EU emissions and type-approval regulations (e.g., CELEX:32007R0715, CELEX:32017R1151).
GOV.UK: Vehicle Approval & V5C
UK vehicle approval processes, import rules, and MoT guidance.
DVLA: Engine Changes & MoT
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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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VCA Certification Portal
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