Nissan MRA8DE

Nissan MRA8DEThe Nissan MRA8DE is a 1.8 l (1,798 cc, 109.7 cu.in.) straight-four 4-stroke natural aspirated gasoline engine from Nissan MR-family.

The MRA8DE 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 MRA8DE is different from the MR18DE as it has a CVTC (continuous variable valve timing system) on both the intake and exhaust camshafts, and uses a diamond-like carbon coating.

The cylinder bore is 79.7 mm (3.14 in) and the piston stroke is 90.1 mm (3.54 in). Compression ratio rating is 9.9:1. The Nissan MRA8DE has an electronic throttle, EGR system and NDIS (Nissan Direct Ignition System) with individual coils on each spark plug.

It produces from 131 PS (96 kW; 129 HP) at 6,400 rpm of horsepower and 174 Nm (17.7 kg·m, 128 lb·ft) at 3,600 rpm of torque.

The breakdown of the engine code is as follows:

  • MR – Engine Family
  • A8* – 1.8 Liter Displacement
  • D – DOHC (Dual Overhead Camshafts)
  • E – Multi Point Fuel Injection

* – engine displacement is increased by 1 cc, so in the engine code, the number 1 was replaced by the letter A.

General information

Engine Specifications
Engine codeMRA8DE
LayoutFour stroke, Inline-4 (Straight-4)
Fuel typeGasoline (petrol)
Production20013-
Displacement1.8 L, 1,798 cm3 (109.7 cu in)
Fuel systemMulti Point Fuel Injection
Power adderNone
Power output 131 PS (96 kW; 129 HP) at 6,400 rpm
Torque output 174 Nm (17.7 kg·m, 128 lb·ft) at 3,600 rpm
Firing order1-3-4-2
Dimensions (L x W x H):
Weight

Cylinder block

The MRA8DE has an aluminum cylinder block with a five-bearings crankshaft supported system. Cylinders in the Nissan MRA8DE 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 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 79.7 mm (3.14 in) and the piston stroke is 90.1 mm (3.54 in). Compression ratio rating is 9.9:1. The Nissan MRA8DE motor has two compression and one oil control rings.

Cylinder block
Cylinder block alloyAluminium
Compression ratio:9.9:1
Cylinder bore:79.7 mm (3.138 in)
Piston stroke:90.1 mm (3.547 in)
Number of piston rings (compression / oil):2 / 1
Number of main bearings:5
Cylinder inner diameter (standard):79.700-79.710 mm (3.1378-3.1382 in)
Piston skirt diameter (standard):79.660-79.670 mm (3.1362-3.1366 in)
Piston pin outer diameter:21.989-21.995 mm (0.8657-0.8659 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)
Oil0.055-0.145 mm (0.0022-0.0057 in)
Piston ring end gap:Top0.20-0.30 mm (0.008-0.012 in)
Second0.29-0.44 mm (0.0114-0.0173 in)
Oil0.15-0.45 mm (0.006-0.018 in)
Connecting rod bushing inner diameter:22.000-22.012 mm (0.8661-0.8666 in)
Connecting rod big end diameter:47.000-47.001 mm (1.8504-1.8504 in)
Connecting rod center distance:138.97-139.07 mm (5.47-5.48 in)
Crankshaft main journal diameter:51.979 mm (2.0464 in)
Crankpin diameter:43.970 mm (1.7311 in)
Crankshaft center distance:44.87-44.89 mm (1.7673-1.7705 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 MRA8DE has continuous variable valve timing system (C-VTC) on both the intake and exhaust camshafts. 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 31.2 mm (1.228 in) in diameter, intake duration is 228°, and the exhaust valves are 25.6 mm (1.008), exhaust duration is 220°. The MRA8DE motor does not have hydraulic lifters, so special valve lifters are used to adjust the valve clearance.

The MRA8DE 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:INTAKE228°
EXHAUST220°
Valve head diameter:INTAKE31.2-31.5 mm (1.228-1.240 in)
EXHAUST25.6-25.9 mm (1.008-1.020 in)
Valve length:INTAKE107.08 mm (4.22 in)
EXHAUST106.06 mm (4.18 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:INTAKE49.4-49.6 mm (1.945-1.953 in)
EXHAUST54.5-54.7 mm (2.146-2.154 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 MR engines are 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 MRA8DE 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
Standard14,1 kg/сm2 (200 psi) / 250 rpm
Minimun12.4 kg/сm2 (177 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 0W-20
Oil type API
Engine oil capacity (Refill capacity) With filter change 4.0 L (4-1/4 US qt, 3-1/2 Imp qt)
Without filter change 3.8 L (4 US qt, 3-3/8 Imp qt)
Oil change interval, km (miles)8,000 (5,000)
Oil Pressure, kPa (bar, kg/cm 2, psi) Idle speed: More than 71 (0.7, 0.72, 10.3)
2,000 rpm: More than 200 (2.0, 2.0, 29)
Ignition system
Spark plugNGK: DILKAR6A-11 (California) or PLZKAR6A-11 (except California)
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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