Nissan LD20 Specifications
| Engine Model: Nissan LD20 |
| Engine Type: 4-cycle 4-cylinder SOHC 8-valve naturally aspirated liquid-cooled diesel |
| Total Displacement: 119.1 cu.in (1.95 L) |
| Rated Engine Power: 60-70 Hp (45-52 kW) at 4600 rpm |
| Fuel System Type: Mechanical fuel injection |
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The Nissan LD20 engine is a 2.0-liter
inline-four, four-stroke diesel engine that became one of Nissan’s most
widely used small-displacement diesel powerplants from the late 1970s
through the 2000s. Designed for compact sedans, vans, taxis, and light
commercial vehicles, the LD20 family includes several versions: the
naturally aspirated LD20 (early type), LD20-II (updated combustion and
block features), LD20T (turbocharged), and LD20T-II (turbocharged with
later refinements and improved fuel-control systems). The LD20 series is
built on principles of durability, fuel economy, low maintenance cost,
and long service life under continuous heavy-duty use.
The LD20’s engineering emphasizes a simple indirect-injection diesel
layout, strong cast-iron block, aluminum or cast-iron cylinder head
depending on version, robust crankshaft with five main bearings,
gear-driven timing components on early models, and belt-driven systems
on later variants. It is known for surviving extreme mileage,
particularly in taxi and commercial fleet applications where engines
frequently exceed 300,000–500,000 km with regular maintenance.
Although not designed for high power output,
the LD20 offers excellent low-rpm torque and outstanding fuel
efficiency, making it ideal for stop-and-go driving, long-distance
transport, and high-load operation.
Because of its simplicity and rugged design, the LD20 family found
widespread use in markets such as Asia, Africa, the Middle East, and
South America. Its ease of overhaul, wide availability of spare parts,
and mechanical injection system helped maintain its popularity long
after more modern diesel engines entered production.
The LD20 is a water-cooled, inline-four diesel engine with a
displacement of 1952 cc (2.0 liters), or approximately 119.1 cubic
inches. Bore is 85.0 mm (3.35 inches), and stroke is 86.0 mm (3.39
inches). This long-stroke configuration produces excellent low- and
mid-range torque, steady idle characteristics, and efficient fuel
consumption typical of diesel engines of its era.
Compression ratios vary between versions:
- LD20 early version: approx. 21.2:1
- LD20-II: approx. 22.0:1
- LD20T / LD20T-II: approx. 20.5:1 to 21.0:1 depending on boost pressure
Power output ranges by version:
- LD20 (early): approx. 60–65 hp (45–48 kW) at ~4600 rpm
- LD20-II: approx. 65–70 hp (48–52 kW) at ~4600 rpm
- LD20T: approx. 78–85 hp (58–63 kW) at ~4400 rpm
- LD20T-II: approx. 85–90 hp (63–67 kW) at ~4400 rpm
Torque output ranges:
- LD20 NA: approx. 100–110 lb-ft (135–150 Nm) at 2400–2600 rpm
- LD20T and LD20T-II: approx. 125–140 lb-ft (170–190 Nm) at 2400–2600
rpm
The firing order for all LD20 versions is 1-3-4-2. Idle speed is
typically 750–800 rpm depending on pump calibration and emission
controls.
The engine block is cast iron, designed with thick cylinder walls
capable of multiple overbores during rebuilds. The crankshaft is a
heavy-duty forged-steel unit supported by five main bearings for
excellent durability and smooth operation under continuous load. Main
bearing sizes and crankshaft geometry are engineered for high endurance
in taxi and commercial fleet use.
Connecting rods are forged steel with large bearing surfaces. Pistons
are aluminum alloy with anodized crowns and reinforced ring lands to
withstand diesel compression pressures. Three piston rings are used: two
compression rings and one oil-control ring. Piston pin fitment varies
between early and later versions but is generally full-floating for
durability.
Cylinder heads differ by generation. Early LD20 engines use a cast-iron
head, while later LD20-II and LD20T versions use an aluminum head with
hardened valve seats. Indirect-injection swirl chambers are cast into
the head, improving cold-start performance and emissions control.
The LD20 uses a single overhead camshaft (SOHC) operating two valves per
cylinder, for a total of eight valves.
Camshaft drive differs by version:
- Early LD20: gear-driven camshaft system
- LD20-II and LD20T: timing-belt-driven camshaft
Valve actuation is via rocker arms, with mechanical valve lash
adjustment required.
Cold valve clearances:
- Intake: approx. 0.30 mm (0.012 in)
- Exhaust: approx. 0.45 mm (0.018 in)
Combustion chambers are precombustion (indirect injection) type,
providing smoother combustion and improved cold-starting.
Fuel delivery is handled by a mechanically controlled diesel fuel
injection system. The LD20 family uses a rotary (distributor-type)
injection pump—typically a Bosch VE licensed unit manufactured by Diesel
Kiki/Zexel. Injection pressures range from 140–160 bar (2030–2320 psi),
depending on version.
Fuel-system characteristics:
- Mechanical governor controlling engine speed
- Fuel cutoff solenoid for engine shutdown
- Lift pump integrated into injection pump
- Inline paper-element fuel filter
- Cold-start advance mechanism
- Glow plug system for preheating
- Turbocharged versions include boost-compensating fuel controls
The LD20T and LD20T-II incorporate aneroid boost-compensation devices to
increase fuel delivery under turbocharged operation. Glow plugs are
essential for cold starting, typically requiring a 5–10 second preheat
period in winter conditions.
The LD20 uses a full-pressure wet-sump lubrication system with a
gear-type oil pump driven by the crankshaft. Oil is distributed to
crankshaft bearings, connecting rod bearings, camshaft bearings, rocker
arms, turbocharger bearings (on turbo models), and timing components.
Oil capacity: Approximately 4.5–5.0 liters (4.8–5.3 US quarts) including
filter
Recommended viscosity: SAE 10W-30, 10W-40, or 15W-40 depending on
climate
Oil pressure:
- At 3000 rpm: 350–450 kPa (50–65 psi)
- Idle: > 70 kPa (>10 psi)
Turbocharged engines require strict oil change intervals to maintain
turbocharger health.
Cooling is handled by a belt-driven centrifugal water pump. Coolant
circulates through the cast-iron block, cylinder head, radiator, and
heater core.
Thermostat operation:
- Begins opening at approx. 82°C (180°F)
- Fully open near 95°C (203°F)
Cooling system capacity:
- Approximately 6.0–7.0 liters (6.3–7.4 US quarts) depending on vehicle
LD20T versions use improved coolant routing and oil-cooling features to
support increased heat load from turbocharging.
| Intake and Exhaust Systems |
Induction varies by version:
- LD20 and LD20-II: naturally aspirated intake manifold
- LD20T / LD20T-II: turbocharger compressor inlet, pressure piping
Exhaust system:
- Cast-iron manifold
- Turbocharger mount flange for LD20T models
- Downpipe with wastegate actuator port (turbo models)
Air filtration uses a replaceable dry paper element.
| Electrical and Starting Systems |
As a diesel engine, the LD20 does not use spark plugs or ignition coils.
Combustion is initiated by compression ignition. The only electrical
system relating to combustion is the glow plug circuit. Glow plug
voltage: 11–12 V rapid glow plugs (varies by version)
Electrical system includes:
- 12-volt charging system
- 60–80 amp alternator depending on application
- Starter motor with reduction gears for cold cranking
Some later LD20T-II versions have ECU-controlled glow plug timing and
idle control, but fuel injection remains fully mechanical.
Turbocharged versions use a small, low-inertia turbocharger (LD20T /
LD20T-II).
Specifications vary by production year but
commonly include:
- Boost pressure: approx. 0.45–0.60 bar (6.5–9 psi)
- Oil-cooled bearing housing
- Internal wastegate
Factory turbocharged versions do not include an intercooler, although
aftermarket conversions often add one for improved performance and lower
exhaust gas temperatures.
- Length: 650–700 mm (25.6–27.6 in)
- Width: 520–540 mm (20.5–21.3 in)
- Height: 650–720 mm (25.6–28.3 in)
Dry weight varies by version:
- LD20 / LD20-II: 150–165 kg (331–364 lb)
- LD20T / LD20T-II: 170–185 kg (375–408 lb) due to turbocharger and
related components
- Oil and filter: every 5000–7000 km (3000–4300 miles)
- Fuel filter: every 20,000–30,000 km
- Air filter: every 20,000 km
- Valve clearance: every 20,000–30,000 km
- Timing belt (LD20-II and turbo): every 80,000–100,000 km
- Glow plugs: inspect every 40,000 km
- Coolant: every 40,000 km or 2 years
- Compression: healthy engines show approx. 400–460 psi (2750–3170 kPa),
<10% variation
- Cylinder head bolts: 110–120 Nm (81–89 lb-ft)
- Main bearing caps: 80 Nm (59 lb-ft)
- Connecting rod bolts: 54 Nm (40 lb-ft)
- Flywheel bolts: 98 Nm (72 lb-ft)
- Crankshaft pulley bolt: 155 Nm (114 lb-ft)
- Intake manifold: 22 Nm (16 lb-ft)
- Exhaust manifold: 28 Nm (21 lb-ft)
- Glow plugs: 15 Nm (11 lb-ft)
- Oil drain plug: 34 Nm (25 lb-ft)
The LD20 engine family powered numerous
Nissan vehicles, including:
- Nissan Bluebird (910, U11, U12)
- Nissan Auster / Stanza
- Nissan Cedric (select markets)
- Nissan Laurel (diesel variants)
- Nissan Vanette / Serena
- Nissan AD Van / Expert
- Nissan Sunny diesel variants (selected regions)
- Taxis and commercial fleet vehicles across Asia, Africa, and the
Middle East
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