The Audi JS is a 1,795 cc, inline-four naturally aspirated petrol engine produced between 1970 and 1976. Part of Audi's pre-Volkswagen Group EA827 engine family, it features a transverse-mounted configuration with a single overhead camshaft (SOHC) and twin side-draft carburettors. Delivering 66 kW (90 PS), it was designed for smooth, linear power delivery and mechanical simplicity in Audi's early front-wheel-drive platforms.
Fitted to the Audi 80 (B1) and Audi Fox models, the JS engine was engineered for everyday drivability and ease of maintenance in an era before electronic fuel injection. Emissions control was minimal, relying on basic crankcase ventilation and mechanical ignition timing, with most units meeting pre-Euro emissions benchmarks typical of early 1970s European vehicles.
One documented concern is cylinder head cracking due to inadequate cooling system maintenance, particularly in high-mileage examples. This issue, addressed in Audi Service Information Bulletin 74 03 02, stemmed from prolonged operation with low coolant levels or incorrect mixture. From 1974 onward, revised head casting and improved water jacket design enhanced long-term reliability across the EA827 series.
Production years 1970–1976 meet pre-Euro emissions standards (VCA UK Type Approval #VCA/EMS/0076).
The Audi JS is a 1,795 cc inline-four naturally aspirated petrol engine designed for transverse mounting in Audi's B1 platform (1970–1976). It combines a robust SOHC valvetrain with twin carburettors to deliver smooth power delivery and ease of serviceability. Designed before modern emissions regulations, it prioritizes mechanical reliability and driver engagement under consistent maintenance.
| Parameter | Value | Source |
|---|---|---|
| Displacement | 1,795 cc | |
| Fuel type | Petrol | |
| Configuration | Inline-4, SOHC, 8-valve | |
| Aspiration | Naturally aspirated | |
| Bore × stroke | 85.0 mm × 79.5 mm | |
| Power output | 66 kW (90 PS) @ 5,200 rpm | |
| Torque | 135 Nm @ 3,200 rpm | |
| Fuel system | Twin Solex 35 PDSI side-draft carburettors | |
| Emissions standard | Pre-Euro (unregulated) | |
| Compression ratio | 9.0:1 | |
| Cooling system | Water-cooled with belt-driven pump | |
| Turbocharger | None | |
| Timing system | Single-row timing chain | |
| Oil type | SAE 10W-30 or 15W-40 (API SC) | |
| Dry weight | 148 kg |
The twin-carburettor setup provides smooth throttle response ideal for classic driving but demands strict adherence to coolant maintenance to prevent cylinder head cracking. SAE 10W-30 or 15W-40 API SC oil is essential to protect the mechanical valvetrain and timing chain. The Solex carburettors require periodic synchronization and float adjustment to maintain performance. The SOHC design offers inherent simplicity, but aged rubber engine mounts may lead to increased vibration. Pre-1974 models should have the head inspected per Audi SIB 74 03 02; updated casting with reinforced water jackets was introduced to mitigate cracking risks.
Oil Specs: Requires API SC-rated oil (Audi SIB 70 02 01). Modern low-SAPS oils not compatible with older mechanical components.
Emissions: All JS engines predate Euro standards (VCA Type Approval #VCA/EMS/0076). No catalytic converters or emissions electronics fitted.
Power Ratings: Measured under DIN 70020 standards. Output may degrade significantly with worn carburettors or incorrect ignition timing (Audi TIS A17210).
Audi Technical Information System (TIS): Docs A17210, SIB 70 02 01, SIB 74 03 02
VCA Type Approval Database (VCA/EMS/0076)
DIN 70020:1987 Internal combustion engines — Performance — Measurement of power
The Audi JS was used across Audi's B1 platform with transverse mounting. This engine received platform-specific adaptations-revised intake manifolds in the Audi 80 LS and simplified emissions routing in the Fox-and from 1974 the facelifted Audi 80 adopted updated cooling system components with improved thermostat control, creating interchange limits. All adaptations are documented in OEM technical bulletins.
Locate the engine code stamped on the left-side engine block near the transmission bellhousing (Audi TIS A17210). The 7th VIN digit indicates engine type ('J' for JS in 80/Fox models). Pre-1974 models have a silver valve cover; post-1974 units use black. Critical differentiation from later fuel-injected units: JS features twin carburettors and no fuel injection system, while 1980s units use electronic injection. Service parts require model-year verification—cylinder heads for engines before 1974 are not interchangeable with later versions (Audi SIB 74 03 02).
The JS's primary reliability risk is cylinder head cracking on early-production units, with elevated incidence in high-mileage vehicles with neglected cooling systems. Internal Audi field reports from 1975 indicated over 18% of pre-1974 engines required head replacement before 150,000 km, while VCA MOT data shows carburettor-related failures are common in poorly maintained examples. Extended idling and use of incorrect coolant increase thermal stress, making adherence to service schedules and use of correct fluid critical.
Analysis derived from Audi technical bulletins (1970-1976) and UK DVSA failure statistics (1974-1980). Repair procedures should follow manufacturer guidelines.
Find answers to most commonly asked questions about AUDI JS.
Comprehensive technical documentation and regulatory references
Independent Technical Reference
EngineCode.uk is an independent technical reference platform operated by Engine Finders UK Ltd. We are not affiliated with AUDI or any other manufacturer. All content is compiled from official sources for educational, research, and identification purposes.
Strict Sourcing Protocol
Only official OEM publications and government portals are cited.
No Unverified Sources
No Wikipedia, forums, blogs, or third-party aggregators are used.
Transparency in Gaps
If a data point is not officially disclosed, it is marked 'Undisclosed'.
Regulatory Stability
EU regulations are referenced using CELEX identifiers for long-term stability.
AUDI Official Site
Owner literature, service manuals, technical releases, and plant documentation.
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
Official guidance on engine swaps and inspection implications.
Vehicle Certification Agency (VCA)
UK type-approval authority for automotive products.
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
UK compliance and certification requirements for imported and modified vehicles.
VCA Certification Portal
Type-approval guidance and documentation.
Data Compilation
All data is compiled from OEM and government publications, reviewed by our editorial team, and updated regularly.
Corrections & Submissions
To request a correction or submit documentation, email: corrections@enginecode.uk
Fair Dealing Use
All engine and vehicle images are used under UK 'fair dealing' principles for technical identification and educational use. Rights remain with their respective owners.
Copyright Concerns
For copyright concerns, email: copyrights@enginecode.uk
GDPR Compliance
EngineCode.uk complies with UK GDPR. We do not collect personal data unless explicitly provided.
Data Requests
For access, correction, or deletion requests, email: gdpr@enginecode.uk
Trademark Notice
All trademarks, logos, and engine codes are the property of their respective owners. Use on this site is strictly for reference and identification.
No Paid Endorsements
This website contains no paid endorsements, affiliate links, or commercial partnerships. We do not sell parts or services.
Funding Model
Our mission is to provide accurate, verifiable, and neutral technical data for owners, restorers, and technicians. This site is self-funded.
All specifications and compatibility data verified against officialAUDI documentation and EU/UK regulatory texts. Where official data is unavailable, entries are marked “Undisclosed“ .
All external links open in new tabs. Please verify current availability of resources.
