Prince G18

Prince G18 engineThe Prince G18 is a carbureted 1.8 liter (1,815 cc, 110.8 cu-in) straight-four, four-stroke cycle gasoline from Prince G-family produced since 1968 to 1975.

The Prince G18 engine is a short-stroke unit with a displacement of 1,815 cm3 (110.8 cu-in). The aluminum alloy cylinder head has cross-flow ports and a V-shaped valve layout. The Prince G18 engine was equipped with a dual barrel down draught type carburetor.

The Prince G18 has an 85.0 mm (3.346 in) cylinder bore and 80.0 mm (3.150 in) piston stroke with a compression ratio of 8.3:1. It produced 105 PS (104 HP, 77 kW) at 5,600 rpm of maximum horsepower and 156 Nm (15.0 kg⋅m, 115 lb⋅ft) at 3,600 rpm of torque.

The breakdown of the engine code is as follows:

  • G – Engine Family
  • 18 – 1.8 Liter Displacement

General information

Engine Specifications
Engine codeL18
LayoutFour stroke, Inline-4 (Straight-4)
Fuel typeGasoline
Displacement1.8 L; 1,815 cm3 (110.8 cu in)
Fuel systemCarburetor
Power adderNone
Max. horsepower105 PS (104 HP, 77 kW) at 5,600 rpm
Max. torque156 Nm (15.0 kg⋅m, 115 lb⋅ft) at 3,600 rpm
Firing order1-3-4-2
Dimensions (L x H x W):

Cylinder block

The G-18 engine has a cast-iron cylinder block, bore is 85.0 mm (3.346 in) and stroke is 80.0 mm (3.150 in). The crankshaft is a carbon steel forging and is provided with five main bearings and four balancing weights Aluminium thrust bearings are located at the №2 journal.

The cast aluminum alloy pistons have two compression rings and one oil ring. Gudgeon pins are fully-floating in the piston bores and are equipped with circlips at each end to limit the amount of their travel. The forged steel connecting rods have weight adjusting bosses at both large and small ends to ensure that the rods are correctly balanced during operation.

Cylinder block
Cylinder block alloyCast iron
Compression ratio:8.3:1
Cylinder bore:85.0 mm (3.346 in)
Piston stroke:80.0 mm (3.150 in)
Number of piston rings (compression / oil):2 / 1
Number of main bearings:5
Cylinder inner diameter (standard):85.0 mm (3.346 in)
Piston skirt diameter (standard):84.968-85.000 mm (3.345-3.346 in)
Piston pin outer diameter:21.991-22.000 mm (0.8658-0.8661 in)
Piston ring side clearance:Top0.040-0.080 mm (0.0016-0.0031 in)
Second0.020-0.060 mm (0.0008-0.0024 in)
Oil0.020-0.060 mm (0.0008-0.0024 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)
Oil0.35-0.55 mm (0.0138-0.0217 in)
Connecting rod center distance:140.0 mm (5.51 in)
Crankshaft journal diameter:55.990 mm (2.2043 in)
Crankpin diameter:49.991 mm (1.968 in)
Crankshaft center distance:40.0 mm (1.5748 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 single overhead camshaft is driven from the crankshaft by a double row roller chain at a
reduction ratio of 2:1. Intake valves are 42.00 mm (1.65 in) in diameter and the exhaust valves are 35.00 mm (1.38 in), valve lift is 9.00 mm (0.345 in) for both sides.

A Stromberg type D3034C carburetor is installed on engines with exhaust emission control and a Solex type DAK340 carburetor on engines not equipped with this type of system.

Cylinder head
Valve Arrangement:OHV, chain drive
Valves:8 (2 valves per cylinder)
Intake/Exhaust duration:
Valve head diameter:INTAKE42.0 mm (1.654 in)
EXHAUST35.0 mm (1.378 in)
Valve guide length:INTAKE48.0 mm (1.890 in)
EXHAUST60.0 mm (2.362 in)
Valve stem diameter:INTAKE8.00 mm (0.31 in)
EXHAUST8.00 mm (0.31 in)
Valve lift:INTAKE9.0 mm (0.354 in)
EXHAUST9.0 mm (0.354 in)
Outer camshaft journal diameter:37.45-37.475 mm (1.474-1.475 in)

Maintenance data

Valve clearance (HOT)
Intake valve0.28 mm (0.011 in)
Exhaust valve0.28 mm (0.011 in)
Valve clearance (COLD)
Intake valve0.25 mm (0.009 in)
Exhaust valve0.25 mm (0.009 in)
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 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 (lb/ (66.8-78.2)
Ignition system
Spark plugBP-6E (NGK)
Spark plug gap0.8-0.9 mm (0.03 -0.035 in)

Vehicle applications

ModelYears Produced
Nissan Skyline 1800 (PC10)1968-1972
Nissan Laurel C301968-1972
Datsun 1800 (C30)1968-1972
Nissan Skyline 1800 (PC110)1972-1975
Nissan Laurel C1301972-1975
Author: Sergei Wers
About: Co-founder and CEO of a multi-brand auto repair shop (engine repair, chassis repair, body repair and painting) for over 15 years. I have been developing internet sites with technical specifications for more than seven years.

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