Nissan QG18DE

Nissan QG18DEThe Nissan QG18DE is a 1.8 liter (1,769 cc, 107.94 cu in) straight-four 4-stroke natural aspirated gasoline engine from Nissan QG-family. The engine was produced since 1999 as substituted of the SR18DE and was discontinued in 2006. The Nissan QG18DE engine received the RJC Technology of The Year Award of 2001

The QG18DE motor has a cast-iron cylinder block and aluminum alloy cylinder head with two overhead camshafts (DOHC). The engine uses multi-point fuel injection system; variable valve timing system on the intake side (NVCT); electronic ignition system with individual ignition coil for each cylinder; electronic throttle body; intake manifold with vortex valves, ERG system, and three-way catalyst. The engine is also equipped with a mixture ratio self-learning control system. Redline is 6,500 rpm. The engine version without variable valve timing system (NVCT) was also available.

The engine has the same cylinder block with QG16DE, but cylinder bore is enlarged to 80.0 mm (3.15 in), piston stroke is the same 88.0 mm (3.46 in). Compression ratio is 9.5:1. It producted from 115 PS (85 KW; 114 HP) at 5,600 rpm to 125 PS (92 KW; 123 HP) at 5,600 rpm of horsepower and from 158 Nm (16.1 kg·m; 116.6 ft·lb) at 4,400 rpm to 165 Nm (16.8 kg·m; 121.8 ft·lb) at 4,400 rpm of torque.

The breakdown of the engine code is as follows:

  • QG – Engine Family
  • 18 – 1.8 Liter Displacement
  • D – DOHC (Dual Overhead Camshafts)
  • E – Multi Point Fuel Injection

Engine systems description

Engine Control System
The QG18DE engine uses the ECCS (Electronic Concentrated engine Control System). This system controls the fuel injection, ignition timing and idle RPM as one single control unit.

Multiport Fuel Injection System (MFI)
The amount of fuel injected from the fuel injector is determined by the engine ECM. The ECM controls the injection pulse duration. The amount of fuel injected is a program value in the ECM memory. The program value is preset by engine operating conditions. These conditions are determined by input signals from the crankshaft position sensor, camshaft position sensor, and the mass air flow sensor.

Two types of fuel enjection timing system are used.

  • Sequential multiport fuel injection is used when the engine is running. Fuel is injected into each cylinder during each engine cycle according to the firing order.
  • Semultaneous multiport fuel injection system is used when the engine is being started or if the fail-safe system is operating. Fuel is injected semultaneously into all four cylinders two times each engine cycle.

Electronic Ignition System (EI)
The Nissan QG18DE ignition system is controlled by the ECU to maintain the best air-fuel ratio for every running condition of the engine. The ignition timing data is stored in the ECM, this data forms the map shown. The ECM receives information such as the injection pulse width and camshaft position sensor signal. Computing this information, ignition signals are transmitted to the power transistor.

General information

Engine Specifications
Engine codeQG18DE
LayoutFour stroke, Inline-4 (Straight-4)
Fuel typeGasoline
Production1999-2006
Displacement1.8 L, 1,769 cm3 (107.94 cu in)
Fuel systemMulti Point Fuel Injection (MFI)
Power adderNone
Power output 115 PS (85 KW; 114 HP) at 5,600 rpm
117 PS (86 KW; 115 HP) at 5,600 rpm
120 PS (88 KW; 118 HP) at 5,600 rpm
122 PS (90 KW; 121 HP) at 5,600 rpm
125 PS (92 KW; 123 HP) at 5,600 rpm
Torque output 158 Nm (16.1 kg·m; 116.6 ft·lb) at 4,400 rpm
161 Nm (16.4 kg·m; 118.8 ft·lb) at 4,400 rpm
163 Nm (16.6 kg·m; 120.3 ft·lb) at 4,400 rpm
165 Nm (16.8 kg·m; 121.8 ft·lb) at 4,400 rpm
Firing order1-3-4-2
Dimensions (L x H x W):
Weight

Cylinder block

The QG18DE motor has a cast-iron cylinder block, cylinder bore is 80.0 mm (3.15 in) and the piston stroke is 88.0 mm (3.46 in). The pistons are each fitted with two compression rings and a single oil ring. The compression ratio is 9.5:1.

The engine uses forged-steel connecting rods with 140.5 mm (5.53 in) length (center distance). The crankshaft main journal diameter is 49.95 mm (1.966 in) and pins journal diameter is 39.97 mm (1.57 in).

Cylinder block
Cylinder block alloyCast iron
Compression ratio:9.5:1
Cylinder bore:80.0 mm (3.150 in)
Piston stroke:88.0 mm (3.465 in)
Number of piston rings (compression / oil):2 / 1
Number of main bearings:5
Block Height:213.95-214.05 mm (8.4232-8.4271 in)
Cylinder inner diameter (standard):80.000-80.010 mm (3.1496-3.1500 in)
Piston skirt diameter (standard):79.965-79.975 mm (3.1482-3.1486 in)
Piston pin outer diameter:18.989-19.001 mm (0.7476-0.7481 in)
Piston ring side clearance:Top0.040-0.080 mm (0.0016-0.0031 in)
Second0.030-0.070 mm (0.0012-0.0028 in)
Oil0.045-0.155 mm (0.0018-0.0061 in)
Piston ring end gap:Top0.20-0.30 mm (0.0079-0.0118 in)
Second0.32-0.47 mm (0.0126-0.0185 in)
Oil0.20-0.60 mm (0.0079-0.0236 in)
Connecting rod center distance:140.45-140.55 mm (5.5295-5.5335 in)
Connectin rod small end inner diameter:19.000-19.012 mm (0.7480-0.7485 in)
Connectin rod big end inner diameter:43.000-43.013 mm (1.6929-1.6934 in)
Crankshaft journal diameter:49.956-49.964 mm (1.9668-1.9671 in)
Crankpin diameter:39.968-39.974 mm (1.5735-1.5738 in)
Crankshaft center distance:43.95-44.05 mm (1.7303-1.7342 in)

Cylinder head

The engine has an aluminum cylinder head with two chain-driven overhead single-piece cast camshafts and sixteen valves (four per cylinder). The QG18DE has a single timing chain. Intake valves are 30.0 mm (1.18 in) in diameter and the exhaust valves are 25.0 mm (0.99). Intake valves duration is 236° and exhaust valves duration is 222° for engines with valve timing control system and 222°/222°, respectively for engines without NVCTS.

The QG18DE does not have hydraulic lifters, so special shims are used to adjust the valve clearance.

Cylinder head
Cylinder head alloyAluminum
Cylinder head height:118 mm (4.6456 in)
Valve Arrangement:DOHC, chain drive
Intake duration: 236° for NVCTS engine
222° for non NVCTS engine
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Exhaust duration:222° for NVCT and non NVCT engine
Valve head diameter:INTAKE29.9-30.2 mm (1.177-1.189 in)
EXHAUST24.9-25.2 mm (0.980-0.992 in)
Valve length:INTAKE92.00-92.50 mm (3.6220-3.6417 in)
EXHAUST92.37-92.87 mm (3.6366-3.6563 in)
Valve stem diameter:INTAKE5.465-5.480 mm (0.2152-0.2157 in)
EXHAUST5.445-5.460 mm (0.2144-0.2150 in)
Cam height (QG18DE with intake valve timing control):INTAKE40.610-40.800 mm (1.5988-1.6063 in)
EXHAUST40.056-40.246 mm (1.5770-1.5845 in)
Outer camshaft journal diameter:№127.935-27.955 mm (1.0998-1.1006 in)
№2-523.935-23.955 mm (0.9423 – 0.9431 in)

Head tightening procedure and torque specs:

  • Step 1: 29.4 Nm; 3.0 kg·m; 22 ft·lb
  • Step 2: 58.8 Nm; 6.0 kg·m; 43 ft·lb
  • Step 3: Loosen all bolts completely
  • Step 4: 29.4 Nm; 3.0 kg·m; 22 ft·lb
  • Step 5: Turn main bolts 50-55° or 58.8 Nm; 6.0 kg·m; 43 ft·lb

Maintenance data

Valve clearance (HOT)
Intake valve0.32-0.40 mm (0.013-0.016 in)
Exhaust valve0.37-0.45 mm (0.015-0.018 in)
Compression pressure
Standard13.5 kg/cm2 (13.25 bar, 192 psi) / 350 rpm
Minimun11.5 kg/cm2 (11.28 bar, 164 psi) / 350 rpm
Compression differential limit between cylinders1 kg/cm2 (0.98 bar, 14 psi) / 350 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, SF, SG, SH or SJ
Engine oil capacity (Refill capacity) With filter change 2.7 l
Without filter change 2.5 l
Oil change interval, km (miles)10,000 (6,000)
Oil Pressure, kPa (bar, kg/cm2 , psi) Idle speed: More than 98 (0.98, 1.0, 14)
2,000 rpm: More than 294 (2.94, 3.0, 43)
6,000 rpm: More than 392 (3.92, 4.0, 57)
Ignition system
Spark plug Standard: BKR5E-11 (NGK), RC10YC4 (Champion)
Hot: BKR4E-11 (NGL)
Cold: BKR6E-11 (NGK)
Spark plug gap1.0 – 1.1 mm (0.039 – 0.043 in)
Spark plug torque19.6-29.4 Nm (2.00-3.00 kg⋅m, 14.3-21.7 lb·ft)

Valve clearance adjustment data

Calculate the thickness of new adjusting shim so valve clearance comes within specified values.

R = Thickness of removed shim
N = Thickness of new shim
M = Measured valve clearance

Intake:
N = R + [M – 0.37 mm (0.0146 in)]
Exhaust:
N = R + [M – 0.40 mm (0.0157 in)]

Shims are available in 50 sizes from 2.00 mm (0.0787 in) to 2.98 mm (0.1173 in), in steps of 0.02 mm (0.0008 in).

Example (intake valve):
R = 2.10 mm
M = 0.52 mm
N = 2.10 + (0.52 – 0.37) = 2.25 mm, so we need a shim with code 225.

For adjustingFor checking
HotCold*Hot
Intake0.32-0.40 mm (0.013-0.016 in)0.25-0.33 mm (0.010-0.013 in)0.21-0.49 mm (0.008-0.019 in)
Exhaust0.37-0.45 mm (0.015-0.018 in)0.32-0.40 mm (0.013-0.016 in)0.30-0.58 mm (0.012-0.023 in)

*: At a temperature of approximately 20°C (68°F)

Whenever valve clearances are adjusted to cold specifications, check that the clearances satisfy hot specifications and adjust again if necessary.

Vehicle applications

ModelYears Produced
Nissan Sentra (B15, N16)2000-2006
Nissan Pulsar (N16)2000-2005
Nissan Primera (P11)1998-2002
Nissan Primera (P12)2002-2007
Nissan Almera (N16)2000-2006
Nissan Almera Tino2000-2006
Nissan Primera1999-2006
Nissan Expert2000-2006
Nissan Avenir1999-2006
Nissan Wingroad (Y11)1999-2005
Nissan AD van (Y11)1999-2005
Nissan Bluebird Sylphy G101999-2005
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10 Comments

  1. Good day,am tongai from Zimbabwe. I replaced my head cylinder from qg18de to qg16. The engine block is for qg18.we how ever head to use the camshafts of qg18 the ones with vvti gear together with the tappet cover with vvt sensor. Every thing is working, no engine check lights except the noise from the head.we did adjust the chain to suit the new head since the original head chain seem shorter. Its the tapping noise that’s bothering me.what should I do to keep it quite

  2. Good night,In my qg 18 engine, if i dont use my car for a day or two, when i go the next day to start the engine wont idle unless i touch the exceleretor pedel slightly and this stops when the engine heats up a little.
    It would usually cut off if i dont excelerate a little.
    I adjusted the idle nut by the trottle but it still happends.
    Any help or suggestions would be appreciated

  3. I’m Michael from Ghàna, a little comment on qg¹8de,when it comes to the piston arrangements,the side which should face the front side of the engine is not clear enough for a Technicians

  4. When doing a self test on the coil packs when i reach the #3 coil pack the engine shuts off. Can u tell me whats the cause. Please.

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