Nissan LD23 Specifications
| Engine Model: Nissan LD23 |
| Engine Type: 4-cycle inline 4-cylinder OHV 8-valve liquid-cooled diesel |
| Total Displacement: 139.7 cu.in (2.29 L) |
| Rated Engine Power: 70-75 Hp (52-57 kW) at 4000 rpm |
| Fuel System Type: Indirect fuel injection |
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The Nissan LD23 engine is a 2.3-liter,
inline-four, four-stroke, water-cooled diesel engine used primarily in
light commercial vehicles, vans, and utility platforms. Introduced
during the 1980s, the LD23 belongs to Nissan’s LD-series of compact
diesel engines engineered for moderate power output, high torque at low
rpm, and exceptional fuel economy.
Known for its conservative but durable architecture, the LD23 uses a
cast-iron block, cast-iron overhead-valve (OHV) cylinder head,
gear-driven timing, and a fully mechanical fuel-injection system. These
design choices result in stable performance, ease of servicing, and long
service life under commercial-duty cycles. The LD23 has been widely used
in Nissan trade vans, people carriers, and export-market utility
vehicles where reliability and minimal maintenance cost are essential.
The LD23 is particularly valued for its low-end torque characteristics,
efficient combustion, and ability to operate on a wide range of diesel
fuel qualities, making it suitable for global markets including regions
with inconsistent fuel standards. While not designed for high-speed
performance, the engine excels at urban cargo delivery, fleet
operations, and rural-use applications requiring dependable, long-lived
powerplants. Its mechanical simplicity also makes it highly rebuildable
and tolerant of extended service intervals.
The Nissan LD23 engine displaces approximately 2,289 cc (2.3 liters /
139.7 cubic inches). Bore is approximately 87.0 mm (3.43 inches), and
stroke is approximately 96.0 mm (3.78 inches), giving the engine a
long-stroke configuration optimized for torque output.
Compression ratio generally ranges from 21.0:1-22.0:1 depending on
vehicle specification and emissions requirements. Maximum power output
is approx. 70-75 Hp at around 4,000 rpm. Maximum torque output is
approx. 110-120 lb-ft (149-163 Nm) at around 2,000 rpm. Idle speed is
approx. 700-750 rpm. The firing order is 1-3-4-2.
The cast-iron block incorporates thick cylinder liners, generous water
jackets, and reinforced bearing saddles to handle continuous load
operation. The forged-steel crankshaft uses five main bearings for
smooth rotation and long-term durability.
Pistons are cast aluminum alloy with reinforced crowns and three-ring
sets. Connecting rods are forged steel with precision-machined big ends
and bushed small ends. The bottom end is engineered for extended life
even in harsh environments.
The cylinder head is cast iron with two valves per cylinder. The engine
uses an overhead-valve (OHV) design with a single camshaft located in
the block. The camshaft is gear-driven and actuates valves via pushrods
and rocker arms. Valve lash is adjustable using threaded rocker-arm
screws. The combustion system is indirect injection (IDI), using
pre-chambers to promote efficient swirl and smooth cold starting. The
IDI design makes the engine quieter and more tolerant of lower-grade
diesel fuel.
Port layout promotes consistent air distribution and effective mixing.
The cast-iron head resists cracking and offers stable operating
temperatures under heavy load. Heads include provisions for glow plugs
that heat the pre-combustion chambers to ensure reliable cold starts.
The LD23 uses a mechanical diesel fuel system designed for robustness
and simplicity.
Components include:
- Mechanical lift pump
- Primary sediment bowl with water separator
- Secondary high-efficiency fuel filter
- Inline mechanical fuel-injection pump (Bosch-type)
- Mechanical multi-hole injectors
- High-pressure steel fuel lines
- Return lines for excess fuel circulation
Injection timing is controlled via the fuel pump and is adjustable by
rotating the pump body. The mechanical governor inside the pump
regulates engine speed and load response. Injector nozzles atomize fuel
into the pre-chambers for clean combustion. Fuel demand is modest,
contributing to excellent fuel economy.
The lubrication system is a full-pressure wet-sump type.
Specifications:
- Oil capacity: approx. 5.5-6.5 liters (5.8-6.9 US qt)
- Oil pressure: approx. 45-60 psi at 3,000 rpm; approx. 15-20 psi at
idle
- Recommended oil: SAE 15W-40 or 10W-30 diesel-rated (API CF-CI)
A crankshaft-driven trochoid pump provides pressurized lubrication to
all major components. The system includes a full-flow spin-on oil
filter. Critical components, including bearings, camshaft journals,
valve lifters, and rocker mechanisms, receive consistent lubrication.
The cooling system is a liquid-cooled, forced-circulation design with a
belt-driven centrifugal water pump.
Specifications:
- Thermostat begins opening at approx. 82°C (180°F)
- Fully open at approx. 95°C (203°F)
- Cooling-system capacity: approx. 8.0-9.0 liters (8.5-9.5 US qt)
- System pressure: approx. 13-15 psi
The cooling system includes block passages, cylinder-head passages,
radiator, thermostat housing, heater core, and bypass systems. Radiators
may be aluminum or copper-brass depending on vehicle model. Regular
coolant replacement prevents scaling, corrosion, and overheating.
| Intake and Exhaust Systems |
The induction system includes:
- Heavy-duty air-cleaner housing
- Replaceable paper air filter
- Intake ducting and snorkel
- Pre-heater intake system for cold-weather operation
Airflow is tuned for low-end torque and efficient combustion. The system
supports clean airflow even in dusty operating conditions.
The exhaust system uses a heavy cast-iron manifold and a single downpipe
arrangement.
Emissions-controlled versions include:
- EGR valve
- Oxidizing catalyst
- Closed crankcase ventilation system
Backpressure is kept moderate to maintain torque output. IDI diesel
engines like the LD23 run relatively quiet and smooth compared to DI
designs.
The LD23 uses a 12-volt electrical system.
Components include:
- Alternator rated approx. 50-70 amps
- Reduction-gear starter motor
- Glow plugs
- Glow-plug relay and controller
- Heavy-duty battery (approx. 70-100 Ah)
Glow plugs provide essential chamber heating for reliable cold starts.
The charging and starting system is designed to meet commercial-duty
requirements.
- Length: approx. 650-700 mm (25.6-27.6 in)
- Width: approx. 580-620 mm (22.8-24.4 in)
- Height: approx. 700-750 mm (27.6-29.5 in)
Dry weight: 180-210 kg (397-463 lb) depending on accessories.
Recommended intervals:
- Engine oil and filter: every 5,000-7,500 km (3,000-5,000 mi)
- Air filter: inspect every 10,000 km; replace as needed
- Fuel filters: every 10,000-20,000 km
- Valve-lash adjustment: every 20,000-30,000 km
- Cooling system flush: every 2 years
- Injection-timing check: every major service
- Glow-plug system inspection: every 20,000 km
Compression pressure:
- Healthy range: approx. 380-450 psi
- Variation between cylinders: less than 10 percent
Idle rpm should remain stable at approx. 700-750 rpm. Injection timing
and valve clearance must be maintained properly for optimal performance.
- Cylinder-head bolts: 110-130 Nm (81-96 lb-ft)
- Main-bearing-cap bolts: 110-130 Nm (81-96 lb-ft)
- Connecting-rod bolts: 70-80 Nm (52-59 lb-ft)
- Flywheel bolts: 130-150 Nm (96-111 lb-ft)
- Intake-manifold bolts: 20-25 Nm (15-18 lb-ft)
- Exhaust-manifold nuts: 30-35 Nm (22-26 lb-ft)
- Injector hold-down bolts: 25-30 Nm (18-22 lb-ft)
- Oil-drain plug: 30-35 Nm (22-26 lb-ft)
The Nissan LD23 engine was used in:
- Nissan Vanette Largo and Vanette Cargo
- Nissan Homy / Caravan (regional models)
- Nissan trade vans and utility platforms
- Export-market vans and light commercial vehicles
- Industrial and agricultural equipment (select markets)
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