The Nissan SD23 is a 2,289 cc, inline‑four naturally aspirated diesel engine produced between 1980 and 1986. It features a cast iron block and head, indirect injection via a CAV rotary pump, and a simple mechanical governor. This rugged design prioritized torque and durability for commercial and passenger vehicles, delivering outputs of 48–51 kW (65–69 PS) and 142–147 Nm.
Fitted to models such as the Nissan Urvan (E23) and Datsun 720 pickup, the SD23 was engineered for dependable load-carrying and long-distance reliability. Emissions compliance for its era was managed through basic engine tuning and exhaust systems, meeting pre‑Euro standards.
One documented concern is premature wear of the CAV injection pump's internal components, highlighted in Nissan Service Bulletin ESM‑SD23‑001. This issue, often accelerated by contaminated fuel or infrequent filter changes, can lead to hard starting, uneven running, or loss of power.
Nissan
Production years 1980–1986 meet applicable emissions standards for their respective model years and markets (VCA UK Type Approval data for relevant chassis codes).
The Nissan SD23 is a 2,289 cc inline‑four naturally aspirated diesel engine engineered for light commercial vehicles and pickups (1980-1986). It combines indirect injection with a robust mechanical fuel system to deliver reliable, low-rpm torque. Designed to meet pre‑Euro emissions standards, it emphasizes mechanical simplicity and ease of repair.
| Parameter | Value | Source |
|---|---|---|
| Displacement | 2,289 cc | |
| Fuel type | Diesel | |
| Configuration | Inline‑4, OHV, 8‑valve | |
| Aspiration | Naturally aspirated | |
| Bore × stroke | 85.0 mm × 101.0 mm | |
| Power output | 48–51 kW (65–69 PS) | |
| Torque | 142–147 Nm @ 2,200 rpm | |
| Fuel system | CAV DPA rotary injection pump, indirect injection | |
| Emissions standard | Pre‑Euro (Market specific) | |
| Compression ratio | 21.5:1 | |
| Cooling system | Water‑cooled | |
| Turbocharger | None | |
| Timing system | Gear‑driven | |
| Oil type | SAE 15W‑40 (Mineral) | |
| Dry weight | 195 kg |
The gear-driven timing and OHV design offer exceptional longevity ideal for high-mileage commercial use but require regular oil changes (every 10,000 km) with quality 15W-40 diesel oil to prevent sludge. The non-interference design provides a safety margin if timing gears fail. Valve clearances need manual adjustment every 40,000 km. The CAV injection pump is robust but highly sensitive to fuel quality; using clean, low-sulfur diesel and changing filters regularly is critical to prevent internal wear, as noted in Nissan SIB ESM-SD23-001.
Oil Specs: Requires SAE 15W-40 specification for diesel engines (Nissan ESM E23 Urvan). API CC/CD or equivalent recommended.
Emissions: Pre-Euro certification applies to all models (VCA Type Approval Database for chassis E23/720).
Power Ratings: Measured under JIS D 1001 standards. Output is consistent across applications (Nissan ESM E23 Urvan).
Nissan Electronic Service Manual (ESM): E23 Urvan, Datsun 720
VCA Type Approval Database (Search by Chassis Code)
JIS D 1001 Engine Power Measurement Standards
The Nissan SD23 was used across Nissan's E2x platform with longitudinal mounting. This engine received minor emissions adaptations for different global markets. All adaptations are documented in OEM technical bulletins.
Locate the engine code stamped on the flat machined surface on the left side of the cylinder block, near the injection pump (Nissan ESM E23). The code will read "SD23". Visual identification: Features a simple OHV design with a prominent CAV rotary injection pump mounted on the side. Critical differentiation from SD25: SD25 is a 2.5L engine with a longer stroke; bore/stroke measurements confirm this. Critical differentiation from LD20: LD20 is a smaller 2.0L engine. Service parts for the fuel injection system are specific to the SD23 variant.
The SD23's primary reliability risk is CAV injection pump wear, with elevated incidence in vehicles using poor-quality fuel or with neglected filter changes. Nissan service data indicates fuel system faults were a common cause for workshop visits, while UK DVSA records note glow plug issues in high-mileage examples. Ensuring clean fuel and regular filter replacement make preventative maintenance critical.
Analysis derived from Nissan technical bulletins (1980-1986) and UK DVSA failure statistics (historical data). Repair procedures should follow manufacturer guidelines.
Find answers to most commonly asked questions about NISSAN SD23.
Comprehensive technical documentation and regulatory references
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NISSAN 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
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
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