Nissan Z20S

The Nissan Z20 or Z20S is a carbureted 2.0 liter (1,952 cc; 121.9 cu-in) liquid-cooled, straight-four, four-stroke cycle, gasoline engine from the Nissan Z-family. The Z20 engine was manufactured from 1979 through 1984. It replaced the Nissan L20B while using many of the same components.

The Nissan Z20S engine features a cast-iron block and aluminum alloy cylinder head with two ignition plugs per cylinder, but for some commercial vehicles, a single-spark plug head was used. It has a single overhead camshaft and 8 valves (2 per cylinder).

It has an 85.0 mm (3.34 in) cylinder bore and 86.0 mm (3.38 in) piston stroke with a compression ratio of 8.5:1 or 9.3:1. The Z20S engine produced up to 110.0 PS (88.0 kW, 108.0 HP) at 5,200 rpm of max. horsepower and 161.0 Nm (16.4 kg·m; 118.8 lbf·ft) at 3,200 rpm of peak torque.

The breakdown of the engine code is as follows:

• Z – Engine Family
• 20 – 2.0 Liter Displacement
• S – Carburetor

General information

Engine Specifications
Engine code	Z20S
Layout	Four stroke, Inline-4 (Straight-4)
Fuel type	Gasoline
Production	1979-1984
Displacement	2.0 L, 1,952 cc (121.9 cu-in)
Max. horsepower	110.0 PS (88.0 kW, 108.0 HP) at 5,200 rpm
Max. torque	161.0 Nm (16.4 kg·m; 118.8 lbf·ft) at 3,200 rpm
Fuel system	Carburetor
Power adder	None
Cooling system	Liquid-cooling
Firing order	1-3-4-2
Dimensions (L x H x W):	–
Weight	–

Cylinder block

The Z20S engine has a cast-iron cylinder block, bore is 85.0 mm (3.34 in) and stroke is 86.0 mm (3.38 in). The cylinder block, a monoblock specially cast structure, employs the five bearing support system. The pistons are each fitted with two compression rings and a single oil ring.

Cylinder block
Cylinder block alloy		Cast iron
Compression ratio:		8.5:1 or 9.3:1
Cylinder bore:		85.0 mm (3.34 in)
Piston stroke:		86.0 mm (3.38 in)
Number of piston rings (compression / oil):		2 / 1
Number of main bearings:		5
Cylinder inner diameter (standard):		85.000-85.050 mm (3.3465-3.3484 in)
Piston skirt diameter (standard):		84.985-85.035 mm (3.3459-3.3478 in)
Piston pin outer diameter:		20.993-20.998 mm (0.8265-0.8267 in)
Piston ring side clearance (Top):		0.040-0.073 mm (0.0016-0.0029 in)
Piston ring side clearance (Second):		0.030-0.063 mm (0.0012-0.0025 in)
Piston ring end gap (Top):		0.250-0.400 mm (0.0098-0.0157 in)
Piston ring end gap (Second):		0.150-0.300 mm (0.0059-0.0118 in)
Piston ring end gap (Oil):		0.300-0.900 mm (0.012-0.035 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:		42.97-43.03 mm (1.6917-1.6941 in)

Cylinder head

The cylinder head is made of a light, strong aluminum alloy with good cooling efficiency. Intake valves are 42.0 mm in diameter and the exhaust valves are 38.0 mm.

Cylinder head
Valve Arrangement:		SOHC, chain drive
Valves:		8 (2 valves per cylinder)
Valve timing (INTAKE):		248°
Valve timing (EXHAUST):		248°
Valve head diameter (INTAKE):		42.0-42.2 mm (1.654-1.661 in)
Valve head diameter (EXHAUST):		38.0-38.2 mm (1.496-1.4504 in)
Valve length (INTAKE):		Datsun 510: 122.8-123.1 mm (4.835-4.846 in) Nissan 720: 124.1-124.4 mm (4.885-4.898 in)
Valve length (EXHAUST):		Datsun 510: 123.6-123.9 mm (4.866-4.878 in) Nissan 720: 125.1-125.4 mm (4.925-4.937 in)
Valve stem outer diameter (INTAKE):		7.965-7.980 mm (0.3136-0.3142 in)
Valve stem outer diameter (EXHAUST):		7.945-7.960 mm (0.3128-0.3134 in)
Camshaft cam height (INTAKE):		Datsun 510: 38.477-38.527 mm (1.5148-1.5168 in) Nissan 720: 38.481-38.531 mm (1.5150-1.5170 in)
Camshaft cam height (EXHAUST):		Datsun 510: 38.477-38.527 mm (1.5148-1.5168 in) Nissan 720: 38.481-38.531 mm (1.5150-1.5170 in)
Outer camshaft journal diameter:		32.935-32.955 mm (1.2967-1.2974 in)

Tightening torque specs

Tightening torque specs
Front cover bolt	M8: 10-16 Nm; 1.0-1.6 kg·m; 7-12 ft·lb M6: 3.9-9.8 Nm; 0.4-1.0 kg·m; 2.9-7.2 ft·lb
Chain guide bolt	5.9-9.8 Nm; 0.6-1.0 kg·m; 4.3-7.2 ft·lb
Chain tensioner bolt	5.9-9.8 Nm; 0.6-1.0 kg·m; 4.3-7.2 ft·lb
Water pump bolt	M8: 10-16 Nm; 1.0-1.6 kg·m; 7-12 ft·lb M6: 3.9-9.8 Nm; 0.4-1.0 kg·m; 2.9-7.2 ft·lb
Crank pulley bolt	118-157 Nm; 12-16 kg·m; 87-116 ft·lb
Water inlet bolt	10-16 Nm; 1.0-1.6 kg·m; 7-12 ft·lb
Water outlet bolt	10-16 Nm; 1.0-1.6 kg·m; 7-12 ft·lb
Intake manifold bolt and nut	16-21 Nm; 1.6-2.1 kg·m; 12-15 ft·lb
Alternator bracket bolt	39-59 Nm; 4.0-6.0 kg·m; 29-43 ft·lb
Alternator to adjusting bar bolt	20-29 Nm; 2.0-3.0 kg·m; 14-22 ft·lb
Engine mounting bracket bolt	29-39 Nm; 3.0-4.0 kg·m; 22-29 ft·lb
Exhaus manifold bolt and nut	16-21 Nm; 1.6-2.1 kg·m; 12-15 ft·lb
EGR tube nut	34-44 Nm; 3.5-4.5 kg·m; 25-33 ft·lb
EAI tube nut	34-44 Nm; 3.5-4.5 kg·m; 25-33 ft·lb
Cylinder head bolt	69-78 Nm; 7.0-8.0 kg·m; 51-58 ft·lb
Cylinder head to front cover bolt	3.9-7.5 Nm; 0.4-0.7 kg·m; 2.9-5.8 ft·lb
Rocker shaft bracket bolt	15-25 Nm; 1.5-2.5 kg·m; 11-18 ft·lb
Camshaft sprocket bolt	118-157 Nm; 12-16 kg·m; 87-116 ft·lb
Rocker arm nut	16-22 Nm; 1.6-2.2 kg·m; 12-16 ft·lb
Main bearing cap bolt	44-54 Nm; 4.5-5.5 kg·m; 33-40 ft·lb
Connecting rod big end nut	44-54 Nm; 4.5-5.5 kg·m; 33-40 ft·lb
Gusset to cylinder block	43-58 Nm; 4.4-5.9 kg·m; 32-43 ft·lb
Flywheel bolt (M/T)	137-157 Nm; 14-16 kg·m; 101-116 ft·lb
Drive plate bolt (A/T)	137-157 Nm; 14-16 kg·m; 101-116 ft·lb
Clutch cover bolt (M/T)	16-21 Nm; 1.6-2.1 kg·m; 12-15 ft·lb
Torque coverter bolt (A/T)	39-49 Nm; 4.0-5.0 kg·m; 29-36 ft·lb
Starter motor bolt	29-39 Nm; 3.0-4.0 kg·m; 22-29 ft·lb
Transmission to cylinder block bolt	43-58 Nm; 4.4-5.9 kg·m; 32-43 ft·lb
Transmission to gusset bolt	43-58 Nm; 4.4-5.9 kg·m; 32-43 ft·lb

Maintenance data

Valve clearance (HOT)
Intake valve	0.30 mm (0.012 in)
Exhaust valve	0.30 mm (0.012 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 5W-40 10W-30 10W-40
Oil type API	SE
Engine oil capacity (Refill capacity)	With filter change: 4.4 liters (4.6 US.qts, 3.9 Imp. qts) Without filter change: 3.9 liters (4.1 US.qts, 3.4 Imp. qts)
Oil change interval, km (miles)	5,000-10,000 (3,000-6,000)
Ignition system
Ignition timing (B.T.D.C./rpm)	6-12°/600 rpm (depends on the country and vehicle model)
Spark plug	Cold: BP7ES, BPR7ES (NGK) Standard: BP6ES, BPR6ES (NGK) Hot: BP5ES, BPR5ES (NGK)
Spark plug gap	0.8-0.9 mm (0.030-0.035 in)
Spark plug tightening torque	15-20 Nm; 1.5-2.0 kg·m; 11-14 ft·lb

Vehicle applications

Model	Years Produced
Datsun 510	1979-1981
Datsun 720	1981
Nissan Cabstar	–
Nissan / Datsun Caravan, Urvan, Hony (E23)	1980-1986
Nissan Laurel C230	1979-1980
Nissan Laurel C31	1980-1984
Datsun D21	–