Nissan MR18DE

Nissan MR18DE engineThe Nissan MR18DE is a 1.8 l (1,797 cc, 109.65 cu.in.) straight-four 4-stroke natural aspirated gasoline engine from Nissan MR-family.

The MR18DE engine features a lightweight aluminum block with a fully balanced five-bearings crankshaft and aluminum head with two camshafts (DOHC) and four valves per cylinder.

The cylinder bore is 84.0 mm (3.3 in) and the piston stroke is 81.1 mm (3.19 in). Compression ratio rating is 9.9:1. The Nissan MR18DE motor has an electronic throttle, continuous variable valve timing system CVTC on the intake camshaft, EGR system and NDIS (Nissan Direct Ignition System) with individual coils on each spark plug.

It produces from 124 to 128 PS (91 to 94 kW; 122 to 126 HP) of horsepower and 173-176 Nm (17.6-17.9 kg·m, 127-130 lb·ft) of torque.

The breakdown of the engine code is as follows:

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

General information

Engine Specifications
Engine codeMR18DE
LayoutFour stroke, Inline-4 (Straight-4)
Fuel typeGasoline (petrol)
Production2005-
Displacement1.8 L, 1,797 cm3 (109.65 cu in)
Fuel systemMulti Point Fuel Injection
Power adderNone
Power output 124 PS (91 kW; 122 HP) at 5,200 rpm
126 PS (93 kW; 125 HP) at 5,200 rpm
128 PS (94 kW; 126 HP) at 5,200 rpm
Torque output 173 Nm (17.6 kg·m, 127 lb·ft) at 4,800 rpm
176 Nm (17.9 kg·m, 130 lb·ft) at 4,800 rpm
Firing order1-3-4-2
Dimensions (L x W x H):
Weight

Cylinder block

The MR-family engines use the same technology as in the HR-series. The MR18DE has an aluminum cylinder block with a five-bearings crankshaft supported system. Cylinders in the Nissan MR18DE engines are fitted at an offset to minimize friction arising from the angle of the connecting rod as a piston descends into the cylinder. The resulting smoother reciprocating motion of the pistons contributes to high power output and high torque as well as fuel economy. Also, the structure is designed so that the piston remains in the upper part of the cylinder longer than in a conventional engine (piston velocity slows down). This permits more efficient use of combustion energy and effectively improves thermal efficiency.

The crankshaft and camshaft journals are finished with a polishing tape to produce a mirror-like finish. The result is a thorough reduction in friction on these bearing surfaces of key engine components. The cylinder bore is 84.0 mm (3.3 in) and the piston stroke is 81.1 mm (3.19 in) and compression ratio rating is 9.9:1. The Nissan MR18DE motor has two compression and one oil control rings.

Cylinder block
Cylinder block alloyAluminium
Compression ratio:9.9:1
Cylinder bore:84.0 mm (3.307 in)
Piston stroke:81.1 mm (3.193 in)
Number of piston rings (compression / oil):2 / 1
Number of main bearings:5
Cylinder inner diameter (standard):84.000-84.010 mm (3.3071-3.3075 in)
Piston skirt diameter (standard):83.970-83.980 mm (3.3059-3.3063 in)
Piston pin outer diameter:19.989-19.995 mm (0.7870-0.7872 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)
Oil0.015-0.185 mm (0.001-0.007 in)
Piston ring end gap:Top0.20-0.30 mm (0.008-0.012 in)
Second0.50-0.65 mm (0.020-0.026 in)
Oil0.15-0.45 mm (0.006-0.018 in)
Connecting rod bushing inner diameter:20.000-20.012 mm (0.7874-0.7879 in)
Connecting rod big end diameter:47.000-47.001 mm (1.8504-1.8504 in)
Connecting rod center distance:143.44-143.54 mm (5.647-5.650 in)
Crankshaft main journal diameter:51.979 mm (2.0464 in)
Crankpin diameter:43.970 mm (1.7311 in)
Crankshaft center distance:40.41-40.49 mm (1.5909-1.5940 in)

Cylinder head

The cylinder head is made of strong, light aluminum alloy which gives it good cooling efficiency. Each camshaft is supported by five bearings. The MR18DE has continuous variable valve timing system (C-VTC) on the intake camshaft. C-VTC enables variable valve timing in response to engine rpm and throttle opening. Enhanced control and reduced system friction improve response and optimize torque characteristics.

Intake valves are 34 mm in diameter, intake duration is 224°, and the exhaust valves are 27.6 mm, exhaust duration is 212°. The MR18DE motor does not have hydraulic lifters, so special valve lifters are used to adjust the valve clearance.

The engine has a plastic intake manifold with an integrated tumble control valve. The MR18DE is equipped with EGR (Exhaust Gas Recirculation) system. This system returns a portion of the exhaust gas to the intake side to reduce fuel consumption and minimize emission.

Cylinder head
Valve Arrangement:DOHC, chain drive
Cylinder head height:130.9 mm (5.15 in)
Valves:16 (4 valves per cylinder)
Valve timing:INTAKE224°
EXHAUST212°
Valve head diameter:INTAKE33.8-34.1 mm (1.331-1.343 in)
EXHAUST27.6-27.9 mm (1.087-1.098 in)
Valve length:INTAKE106.27 mm (4.184 in)
EXHAUST105.26 mm (4.144 in)
Valve stem diameter:INTAKE5.465-5.480 mm (0.2152-0.2157 in)
EXHAUST5.455-5.470 mm (0.2148-0.2154 in)
Valve spring free length:INTAKE44.90-45.10 mm (1.7677-1.7755 in)
EXHAUST45.74-45.94 mm (1.8007-1.8086 in)
Camshaft cam height:INTAKE44.605-44.795 mm (1.7560-1.7635 in)
EXHAUST43.175-43.365 mm (1.6997-1.7072 in)
Camshaft journal diameter:№127.935-27.955 mm (1.0998-1.1006 in)
№2, 3, 4, 524.950-24.970 mm (0.9823-0.9381 in)

Head tightening procedure and torque specs:

  • Step 1: 40 Nm; 4.1 kg·m; 30 ft·lb
  • Step 2: Turn all bolts 100°
  • Step 3: Loosen all bolts completely
  • Step 4: 40 Nm; 4.1 kg·m; 30 ft·lb
  • Step 5: Turn all bolts 100°
  • Step 6: Turn all bolts another 100°

Problems and malfunctions

The Nissan MR18 is reliable and durable. This engine sometimes has a problem with alternator belt (whistle noise). It needs to tighten or replace the old belt by a new one.

The engine has a timing chain, their service life is about 150,000 miles of mileage (200,000-250,000 km). The valve clearance needs to be adjusted every 60,000 miles of mileage (90,000 km). The MR18DE motor life expectancy is 200,000 miles of mileage (300,000 km) or more.

Maintenance data

Valve clearance (HOT)
Intake valve0.304-0.416 mm (0.012-0.016 in)
Exhaust valve0.308-0.432 mm (0.012-0.017 in)
Compression pressure
Standard15.3 kg/сm2 (217 psi) / 250 rpm
Minimun12.2 kg/сm2 (174 psi) / 250 rpm
Compression differential limit between cylinders1.0 kg/сm2 (15 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
Engine oil capacity (Refill capacity) With filter change 4.1 L (4-3/8 US qt, 3-5/8 Imp qt)
Without filter change 3.8 L (4 US qt, 3-3/8 Imp qt)
Oil change interval, km (miles)6,000 (3,750)
Oil Pressure, kPa (bar, kg/cm 2, psi) Idle speed: More than 60 (0.6, 0.61, 9)
2,000 rpm: More than 200 (2.0, 2.0, 29)
Ignition system
Spark plugDENSO: FXE20HR11
Spark plug gap1.1 mm (0.043 in)
Spark plug tightening torque19.6 Nm; 2.0 kg·m; 14 ft·lb

Valve clearance adjustment data

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

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

Intake:
N = R + [M – 0.30 mm (0.012 in)]
Exhaust:
N = R + [M – 0.33 mm (0.013 in)]

Valve lifters are available in 26 sizes range from 3.00 mm (0.1181 in) to 3.50 mm (0.1378 in), in steps of 0.02 mm (0.0008 in).

Example (intake valve):
R = 3.10 mm
M = 0.52 mm
N = 3.10 + (0.52 – 0.30) = 3.32 mm, so we need a valve lifter with identification mark 332.

ColdHot
Intake0.26 – 0.34 mm (0.010 – 0.013 in)0.304 – 0.416 mm (0.012 – 0.016 in)
Exhaust0.29 – 0.37 mm (0.011 – 0.015 in)0.308 – 0.432 mm (0.012 – 0.017 in)

Vehicle applications

ModelYears Produced
Nissan Tiida (JC11)2004–2012
Nissan Versa (JC11)2004–2012
Nissan Grand Livina2006–present
Nissan Wingroad (Y12)2006–present
Nissan AD (Y12)2006–present
Nissan Cube2009-2014
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