Nissan L20A

Nissan L20AThe Nissan / Datsun L20A is a carbureted 2.0 liter (1,998 cc, 121.9 cu-in) straight-six, four-stroke cycle gasoline engine from Nissan L-family. The L20A was introduced in 1969 for the 1970 model year Nissan Fairlady Z, as well as in the new Cedric. The L20A in-line six engine was based on the design of the L16.

The Nissan (Datsun) L20A engine features a cast-iron block, a wedge-shaped combustion chamber, aluminum head with overhead camshaft and a fully balanced 7-bearing crankshaft. The cylinder block is cast in a single unit and features deep skirting.

The L20A was an over-square design with 78 mm (3.07 in) cylinder bore and 69.7 mm (2.75 in) piston stroke and 9.0:1 compression with twin side draft carb’s or 8.6:1 with a single carb. It produced from 115 PS (114 HP, 85 kW) to 130 PS (129 HP, 96 kW) of horsepower and from 162 Nm (16.5 kg⋅m; 120 ft-lb) to 172 Nm (17.5 kg⋅m; 127 ft-lb) of torque.

The breakdown of the engine code is as follows:

  • L – Engine Family
  • 20 – 2.0 Liter Displacement

General information

Engine Specifications
Engine code L20A
Layout Four stroke, Inline-6 (Straight-6)
Fuel type Gasoline
Displacement 2.0 L, 1,998 cm3 (121.9 cu in)
Fuel system Single or Twin carburetor
Power adder None
Max. horsepower 115 PS (114 HP, 85 kW) at 5,600 rpm (Single carb, regular gas.)
120 PS (119 HP, 88 kW) at 5,600 rpm (Single carb, high-octane gas.)
125 PS (124 HP, 92 kW) at 6,000 rpm (Twin carb, regular gas.)
130 PS (129 HP, 96 kW) at 6,000 rpm (Twin carb, high-octane gas.)
Max. torque 162 Nm (16.5 kg⋅m; 120 ft-lb) at 3,600 rpm (Single carb, regular gas.)
167 Nm (17.0 kg⋅m; 125 ft-lb) at 3,600 rpm (Single carb, high-octane gas.)
167 Nm (17.0 kg⋅m; 125 ft-lb) at 4,400 rpm (Twin carb, regular gas.)
172 Nm (17.5 kg⋅m; 127 ft-lb) at 4,400 rpm (Twin carb, high-octane gas.)

Firing order 1-5-3-6-2-4
Dimensions (L x H x W):

Cylinder block

The L20A engine has a cast-iron cylinder block, bore is 78 mm (3.07 in) and stroke is 69.7 mm (2.75 in). The cylinder block, a monoblock specially cast structure, employs the seven bearing support system for quietness and higher durability. The pistons are each fitted with two compression rings and a single oil ring. The crankshaft of L20A engine is made of special forged steel.

Cylinder block
Cylinder block alloy Cast iron
Compression ratio: Single carb: 8.6:1
Twin carb: 9.0:1
Cylinder bore: 78 mm (3.07 in)
Piston stroke: 69.7 mm (2.75 in)
Number of piston rings (compression / oil): 2 / 1
Number of main bearings: 7
Cylinder inner diameter (standard): 78.000 mm (3.071 in)
Piston skirt diameter (standard): 77.915-77.965 mm (3.0675-3.0695 in)
Piston pin outer diameter: 20.993-20.998 mm (0.8265-0.8267 in)
Piston ring side clearance: Top 0.040-0.080 mm (0.0016-0.0031 in)
Second 0.040-0.080 mm (0.0016-0.0031 in)
Piston ring end gap: Top 0.20-0.35 mm (0.0079-0.0138 in)
Second 0.14-0.29 mm (0.0055-0.0114 in)
Oil 0.30-0.90 mm (0.012-0.035 in)
Piston ring height: Top 1.977 mm (0.0778 in)
Second 1.977 mm (0.0778 in)
Connecting rod center distance: 133.00 mm (5.24 in)
Crankshaft journal diameter: 54.942-54.955 mm (2.1631-2.1336 in)
Crankpin diameter: 49.961-49.974 mm (1.9670-1.9675 in)
Crankshaft center distance: 34.85 mm (1.3720 in)

Cylinder head

The cylinder head is made of a light, strong aluminum alloy with good cooling efficiency. The camshaft is made of specially cast iron and is located inside the rocker cover. The intake manifold is cast aluminum and exhaust manifold is cast iron.

Cylinder head (Single carb specs)
Valve Arrangement: OHV, chain drive
Valves: 12 (2 valves per cylinder)
Intake/Exhaust duration: 232° / 240°
Valve head diameter: INTAKE 38.0 mm (1.50 in)
EXHAUST 33.0 mm (1.31 in)
Valve length: INTAKE 115.6-115.9 mm (4.551-4.562 in)
EXHAUST 115.7-116.0 mm (4.555-4.567 in)
Valve stem diameter: INTAKE 7.965-7.980 mm (0.3136-0.3142 in)
EXHAUST 7.945-7.960 mm (0.3128-0.3134 in)
Outer camshaft journal diameter: 47.949-47.962 mm (1.8878-1.8883 in)

Tightening torque specs

Tightening torque specs
Cylinder head bolt Step 1: 40 Nm; 4.0 kg·m; 28 ft·lb
Step 2: 60 Nm; 6.0 kg·m; 43 ft·lb
Step 3: 73-83 Nm; 7.5-8.5 kg·m; 54-61 ft·lb
Connecting rod big end nut 37-44 Nm; 3.7-4.3 kg·m; 27-31 ft·lb
Flywheel bolt 127-146 Nm; 13.0-15.0 kg·m; 94-108 ft·lb
Camshaft sprocket bolt 127-147 Nm; 13.0-15.0 kg·m; 94-108 ft·lb
Main bearing cap bolt 44-54 Nm; 4.5-5.5 kg·m; 33-40 ft·lb
Crank pulley bolt 127-147 Nm; 13.0-15.0 kg·m; 94-108 ft·lb
Rocker pivot lock nut 49-59 Nm; 5.0-6.0 kg·m; 36-46 ft·lb

Maintenance data

Valve clearance (HOT)
Intake valve 0.25 mm (0.010 in)
Exhaust valve 0.30 mm (0.012 in)
Valve clearance (COLD)
Intake valve 0.20 mm (0.008 in)
Exhaust valve 0.25 mm (0.010 in)
Compression pressure
Standard 12.0 kg/cm2 (11.77 bar, 171 psi) / 350 rpm
Minimun 9.0 kg/cm2 (8.83 bar, 128 psi) / 250 rpm
Oil system
Oil consumption , L/1000 km (qt. per miles) up to 0.5 (1 qt. per 1200 miles)
Recommended engine oil 5W-30
Oil type API SE
Engine oil capacity (Refill capacity) Maximum (H level): 5.0 l (1.3 US gal)
Minimum (L level): 3.9 l (1.0 US gal)
Oil change interval, km (miles) 5,000-10,000 (3,000-6,000)
Ignition system
Spark plug Cold: BP7ES, L44PW, BPR7ES
Standard: BP6ES, L45PW, BPR6ES
Spark plug gap 0.8-0.9 mm (0.03 -0.035 in)

Vehicle applications

Model Years Produced
Nissan Laurel (HLC210) 1975–1977
Datsun 200L (HLC210) 1975–1977
Nissan Bluebird U 2000 GT and GTX
Nissan Cedric (230/330)
Nissan Laurel (HIJC31) 1981–1985
Nissan Fairlady Z 1970-1983
Nissan Gloria (A30)
Datsun 2000 (130)
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