Nissan L18

Nissan L18 Single-carb engineThe Nissan / Datsun L18 is a carbureted 1.8 liter (1,770 cc, 108.01 cu in) straight-4, four-stroke cycle gasoline engine from Nissan L-family. The Nissan L18 motor produced from 1972 through 1976.

The Nissan-Datsun L18 engine feature OHC valves, wedge-shaped combustion chamber, aluminum cylinder head and fully balanced five-bearing crankshaft to turn out smooth, dependable power. The L18 engine uses eight balance weights. The cylinder block is cast in a single unit, featuring deep skirting. The engine is equipped with single, 2-barrel, downdraft carburetor.

The L18 engine with SU twin carburetor was also available, it was called L18T. This engine had higher compression pistons, lower volume combustion chambers, higher compression ratio, higher output power, and torque.

The L18 engine has an 85.0 mm (3.35 in) cylinder bore and 78.0 mm (3.07 in) piston stroke with a compression ratio of 8.5:1. It produced 105 PS (103 HP, 77 kW) at 6,000 rpm and 147 Nm (15.0 kg·m, 108 lb·ft) at 3,600 rpm .

The breakdown of the engine code is as follows:

  • L – Engine Family
  • 16 – 1.8 Liter Displacement

General information

Engine Specifications
Engine codeL18
LayoutFour stroke, Inline-4 (Straight-4)
Fuel typeGasoline
Production
Displacement1.8 L, 1,770 cm3 (108.017 cu in)
Fuel systemSingle carburetor
Power adderNone
Max. horsepower 105 PS (103 HP, 77 kW) at 6,000 rpm
Max. torque 147 Nm (15.0 kg·m, 108 lb·ft) at 3,600 rpm
Firing order1-3-4-2
Dimensions (L x H x W):
Weight

Cylinder block

The Nissan L18 motor has a cast-iron cylinder block. The cylinder block, which is of a monoblock special casting structure, adopts the five-bearing-support system. The cylinder bores are surrounded by cooling jackets and machined directly in the block. The oilways in the block are arranged so that the full-flow oil filter is directly attached to the right-hand side of the block. The Nissan L16 engine cylinder bore is 85.0 mm (3.35 in) and the piston stroke is 78.0 mm (3.07 in), compression ratio rating is 8.5:1.

The crankshaft is a special steel forging. Fully balanced, it turns out smooth, dependable power at high speed. Main bearings gain lubrication from oil pumped through the main oil gallery and the oil holes which run in parallel with cylinder bores.

The pistons are special aluminum casting with struts to control thermal expansion and have two compression rings and one combined oil ring. The piston pin is a special hollow steel shaft. It is full-floating fit to the piston and press-fit to the connecting rods. The connecting rods are special forged steel.

Cylinder block
Cylinder block alloyCast iron
Compression ratio:8.5:1
Cylinder bore:85.0 mm (3.35 in)
Piston stroke:78.0 mm (3.07 in)
Number of piston rings (compression / oil):2 / 1
Number of main bearings:5
Cylinder inner diameter (standard):85.000 mm (3.346 in)
Piston skirt diameter (standard):84.985-85.035 mm (3.3459-3.3478 in)
Piston pin outer diameter:20.995-21.000 mm (0.8266-0.8268 in)
Piston ring side clearance:Top0.045-0.080 mm (0.0018-0.0031 in)
Second0.030-0.070 mm (0.0012-0.0028 in)
Piston ring end gap:Top0.35-0.55 mm (0.0138-0.0217 in)
Second0.30-0.50 mm (0.0118-0.0197 in)
Oil0.30-0.90 mm (0.012-0.035 in)
Connecting rod center distance:130.35 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:39.00 mm (1.5354 in)

Cylinder head

The cylinder head is made of light and strong aluminum alloy with good cooling efficiency; it contains wedge-type combustion chambers. A special aluminum bronze valve seat is used on the intake valve, while a heat resistant steel valve seat is installed on the exhaust valve. These parts are all hot press-fitted.

The camshaft is made of special cast iron and located inside rocker cover. Four aluminum alloy brackets support camshaft. Camshaft bearings are lubricated from oil holes which lead to the main oil gallery of the cylinder head. The valve system has a pivot type rocker arm that is activated directly by the cam mechanism. The Nissan L18 motor use the dual-type valve springs. Intake valves are 42 mm (1.65 in) in diameter and the exhaust valves are 35 mm (1.37 in). The intake valve duration is 240°, valve lift is 10.0 mm (0.39 in); the exhaust valve duration is 248°, valve lift is 10.5 mm (0.41 in).

The camshaft is driven by a double row roller chain driven by the crankshaft. The tension of the chain is controlled by a chain tensioner which is operated by spring and oil pressure.

Cylinder head
Valve Arrangement:OHV, chain drive
Valves:8 (2 valves per cylinder)
Intake/Exhaust duration:240°/248°
Valve head diameter:INTAKE42.0 mm (1.6535 in)
EXHAUST35.0 mm (1.3780 in)
Valve length:INTAKE114.9-115.2 mm (4.524-4.535 in)
EXHAUST115.7-116.0 mm (4.555-4.567 in)
Valve stem diameter:INTAKE7.965-7.980 mm (0.3136-0.3142 in)
EXHAUST7.945-7.960 mm (0.3128-0.3134 in)
Valve spring free length:INTAKE Outer: 49.98 mm (1.968 in)
Inner: 44.85 mm (1.766 in)
EXHAUST Outer: 49.98 mm (1.968 in)
Inner: 44.85 mm (1.766 in)
Camshaft robe lift:INTAKE6.65 mm (0.2618 in)
EXHAUST7.00 mm (0.2753 in)
Rocker arm lever ratio:1.45
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; 28.9 ft·lb
Step 2: 60 Nm; 6.0 kg·m; 43.4 ft·lb
Step 3: 60-85 Nm; 6.5-8.5 kg·m; 47.0-61.5 ft·lb
Connecting rod big end nuts44-54 Nm; 4.5-5.5 kg·m; 33-40 ft·lb
Flywheel bolt137-157 Nm; 14.0-16.0 kg·m; 101-116 ft·lb
Main bearing cap bolt31-37 Nm; 3.2-3.8 kg·m; 23-27 ft·lb
Camshaft sprocket bolt118-157 Nm; 12.0-16.0 kg·m; 87-116 ft·lb
Oil pan bolts6-9 Nm; 0.6-0.0 kg·m; 4.3-6.5 ft·lb
Oil pump bolt11-15 Nm; 1.1-1.5 kg·m; 8-11 ft·lb
Oil pan drain plug20-30 Nm; 2.0-3.0 kg·m; 14-22 ft·lb
Rocker pivot lock nut49-59 Nm; 5.0-6.0 kg·m; 36-44 ft·lb
Camshaft locating plate bolts6-9 Nm; 0.6-0.0 kg·m; 4.3-6.5 ft·lb
Manifold nuts8-12 Nm; 0.8-1.2 kg·m; 5.8-8.7 ft·lb
Fuel pump nuts12-18 Nm; 1.2-1.8 kg·m; 8.7-13.0 ft·lb
Crank pulley nut118-157 Nm; 12.0-16.0 kg·m; 87-116 ft·lb

Maintenance data

Valve clearance (HOT)
Intake valve0.25 mm (0.010 in)
Intake valve0.30 mm (0.012 in)
Valve clearance (COLD)
Intake valve0.20 mm (0.008 in)
Exhaust valve0.25 mm (0.010 in)
Compression pressure
Standard12.0 kg/cm2 (11.77 bar, 171 psi) / 350 rpm
Minimun9.0 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 APISE
Engine oil capacity (Refill capacity) Hight level: 4.3 l
Low level: 3.3 l
Oil change interval, km (miles)5,000-10,000 (3,000-6,000)
Oil pressure, kg/cm2 (psi)3.5-4.2 (49.8-56.9) at 2,000 rpm
Ignition system
Spark plugBP5ES (NGK)
Spark plug gap0.8-0.9 mm (0.03-0.035 in)
Spark plug tightening torque15-25 Nm; 1.5-2.5 kg·m; 11-15 ft·lb

Vehicle applications

ModelYears Produced
Nissan Bluebird1971-1976
Datsun 180B1971-1976
Nissan 160B sedan (610)1971–1977
Nissan Bluebird (P510)1973
Datsun 1600 SSS (P510)1973
Datsun 6101973
Datsun 620 truck1974
Datsun 7101974
Datsun 180SX1979–1981
Datsun 7201980–1986
Datsun 810
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We try to use verified sources and official documentation, however, differences between sources or errors in entering information may occur. We do not provide advice on technical issues related to the engines operation or repair. We do not recommend using provided information for engines repairing engines or spare parts ordering, use only official service manuals and spare-parts catalogs.

6 Comments

  1. good day I appreciate your guidelines and specifications can you please mail me a guideline to assembling my l18j Nissan stanza single carb engine. Will be highly greatfull.

    Regards bruce

  2. THANK YOU FOR YOUR ASSISTANCE CAN YOU KINDLY SEND ME A GUIDELINE ON HOW TO BREAK AND REBUILT MY DATSUN 1800

    THANK YOU

  3. My L18 skyline is not performing normal when I accelerate it picks up after some time. I cleaned the carb but no difference. I wonder what the problem is. Please help me get it back to normal condition.

  4. Hello, thank you very much for the information provided here!
    Do you really have a guideline to rebuild a Datsun 180B, can you please send it to my email ?

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