The Nissan L20A is a 1,998 cc, inline‑six naturally aspirated petrol engine produced between 1970 and 1979. It features an OHV, 12‑valve design with a single downdraft carburettor, prioritising mechanical simplicity and low-cost ownership. Output is modest at approximately 77 kW (105 PS) and 157 Nm, suitable for light commercial and passenger vehicle applications.
Fitted primarily to the Nissan Skyline (C10/C110), Nissan Laurel (C130), and Nissan Cedric/Gloria (230/330), the L20A was engineered for dependable, low-stress performance. Emissions control for its era was minimal, relying on basic carburettor calibration to meet prevailing national standards.
A documented service consideration involves valve clearance adjustment, which requires periodic inspection as per Nissan Service Manual Section EM-L20A. The engine’s robust, non-interference design and simple OHV layout contributed to its reputation for longevity with basic maintenance.
Nissan
Production years 1970–1979 predate formal Euro standards; compliance based on national regulations of the era (VCA UK Type Approval records for period vehicles).
The Nissan L20A is a 1,998 cc inline‑six naturally aspirated petrol engineered for mid-size sedans and coupes (1970-1979). It combines a simple OHV valvetrain with carburetted fuel delivery to deliver smooth, low-stress performance. Designed for pre‑Euro regulatory environments, it prioritises mechanical durability over high output.
| Parameter | Value | Source |
|---|---|---|
| Displacement | 1,998 cc | |
| Fuel type | Petrol | |
| Configuration | Inline‑6, OHV, 12‑valve | |
| Aspiration | Naturally Aspirated | |
| Bore × stroke | 78.0 mm × 69.7 mm | |
| Power output | 77 kW (105 PS) @ 5,400 rpm | |
| Torque | 157 Nm @ 3,600 rpm | |
| Fuel system | Single downdraft carburettor (Hitachi or Nissan) | |
| Emissions standard | Pre-Euro (National regulations) | |
| Compression ratio | 8.8:1 | |
| Cooling system | Water‑cooled | |
| Turbocharger | None | |
| Timing system | Chain-driven | |
| Oil type | API SF (SAE 10W-30 or 20W-50) | |
| Dry weight | Not specified in available OEM docs |
The L20A offers smooth, linear power ideal for relaxed cruising but lacks modern acceleration. Regular oil changes (every 5,000-8,000 km) with API SF spec oil are crucial. Valve clearances require periodic manual adjustment (typically every 20,000-30,000 km) to maintain performance and prevent valve train noise. The carburettor requires cleaning and adjustment for optimal running. Its non-interference design provides a safety margin if the timing chain fails.
Oil Specs: Requires API SF specification oil (Nissan Owner's Manual). Modern equivalents meeting API SG/SH are suitable.
Emissions: Pre-dates formal Euro standards; compliance based on 1970s UK national vehicle regulations (VCA Historical Records).
Power Ratings: Measured under JIS D 1001 standards (Nissan Technical Data Sheet TDS-L20A/70). Output is consistent across applications.
Nissan Workshop Manual: Section EM-L20A
Nissan Parts Catalogue (EPC): Doc. L20A-001
Nissan Technical Data Sheet: TDS-L20A/70
UK Vehicle Certification Agency (VCA) Historical Type Approval Database
The Nissan L20A was used across Nissan's C10/C110 and C130/230 platforms with longitudinal mounting. This engine received minor platform-specific adaptations-different engine mounts and ancillary bracketry for the Laurel-but no major revisions occurred during its production, ensuring broad parts interchangeability. All adaptations are documented in OEM technical bulletins.
Locate the engine code stamped on a flat pad on the cylinder block, typically on the exhaust side near the rear of the engine (Nissan Workshop Manual EM-L20A). The engine code will read "L20A". Visually, it is identifiable by its inline-six configuration, OHV design (rocker cover on top, pushrods visible underneath), single downdraft carburettor, and lack of fuel injection or overhead camshafts. Differentiate from the larger L24 by displacement (2.0L vs 2.4L) and specific engine mount configurations.
The L20A's primary reliability consideration is wear in the valve train and carburettor system, with elevated incidence in high-mileage or poorly maintained units. Nissan workshop data indicates valve clearance adjustment and carburettor servicing are common requirements, while UK DVSA MOT records for surviving vehicles often cite emissions failures linked to incorrect mixture or worn components. Adherence to maintenance schedules is critical for sustained operation.
Analysis derived from Nissan technical bulletins (1970-1979) and UK DVSA failure statistics (for applicable vintage vehicles). Repair procedures should follow manufacturer guidelines.
Find answers to most commonly asked questions about NISSAN L20A.
Comprehensive technical documentation and regulatory references
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NISSAN 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.
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