Nissan MR16DDT / Renault M5M

The Nissan MR16DDT is a 1.6 l (1,618 cc, 98.78 cu.in.) straight-four 4-stroke turbo-charged gasoline engine from Nissan MR-family. The MR16DDT also called DIG-T (Direct Injection Gasoline Turbo-charged) engine. The MR16DDT engine was co-developed with Renault and in the Renault production line it is called M5M.

The MR16DDT (M5M) features a lightweight aluminum block with a fully balanced five-bearings crankshaft and aluminum head with two camshafts (DOHC) and four valves per cylinder.

Compression ratio rating is 9.5-10.5:1. Cylinder bore and piston stroke are 79.7 mm (3.138 in) and 81.1 mm (3.193 in), respectively. The MR16DDT (M5M) engine has an electronic throttle, continuous variable valve timing system on both shafts (Twin CVTC), electronic ignition with individual coils on each spark plug, direct injection mechanism and turbocharger.

The power output is from 188 HP (140 kW; 190 PS) at 5,600 rpm up to 215 HP (160 kW; 218 PS) at 6,000 rpm on Nissan Juke RS NISMO. The torque is 240-280 Nm (24.5-28.5 kg·m, 177-206.5 lb·ft) of torque.

The breakdown of the engine code is as follows:

• MR – Engine Family
• 16 – 1.6 Liter Displacement
• D – DOHC (Dual Overhead Camshafts)
• D – Direct Cylinder Fuel Injection
• T – Turbocharged

General information

Cylinder block

Cylinders in the Nissan MR16DDT / Renault M5M 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 MR-family engines have cracking-processed connecting rods. These integrally cast con rods offer lighter weight than conventional con rods, which are constructed in two parts, separated at the eye where they join the crankshaft. The cracking processed conrod is manufactured in one piece, then the lower connecting rod eye is broken in two (the cracking process) and, finally, the two parts are rejoined after mounting. Mating of the uneven surfaces created by the cracking process results in a very precise joint.

The crankshaft 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. Cylinder bore of the MR16DDT (M5M) is 79.7 mm (3.138 in) and stroke is 81.1 mm (3.193 in). The compression ratio rating is 9.5:1 or 10.5:1 depending on the car model. The pistons are each fitted with two compression rings and a single oil ring.

Main bearing cap bolts tightening procedure and torque specs:

• Step 1: 34.3 Nm; 3.5 kg·m; 25 ft·lb
• Step 2: Turn all bolts 70°

After securing bearing cap bolts, make sure crankshaft turns smoothly by hand.

Connecting rod bearing bolts

• Step 1: 27.4 Nm; 2.8 kg·m; 20 ft·lb
• Step 2: 0 Nm; 0 kg·m; 0 ft·lb
• Step 3: 19.6 Nm; 2.0 kg·m; 14 ft·lb
• Step 4: Turn all bolts 60°

Crankshaft pulley bolt

• Step 1: 29.4 Nm; 3.0 kg·m; 22 ft·lb
• Step 2: Turn another 60 degrees clockwise

Flywheel (M/T) or Drive plate (CVT) fixing bolts

• 108 Nm; 11 kg·m; 80 ft·lb

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 MR16DDT (M5M) has twin continuous variable valve timing system (CVTC) on 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.

The surface of the camshafts has been nano-finish coated. The nano-finished camshaft polished smooth like a mirror and the DLC valve lifter achieve a major reduction in friction. The top of the beehive valve spring has narrowed, realizing compact retainers and also further contributing to friction reduction.

Intake valves are 31.3 mm in diameter, intake duration is 228°, and the exhaust valves are 25.7 mm, exhaust duration is 228°. The MR16DDT motor does not have hydraulic lifters, so special valve lifters are used to adjust the valve clearance.

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 95°
• Step 6: Turn all bolts another 95°

Camshaft sprocket bolts

• Step 1: 35.0 Nm; 3.6 kg·m; 26 ft·lb
• Step 2: Turn all bolts 30°

Problems and malfunctions

The Nissan MR16DDT is reliable and durable. 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).

Maintenance data

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.

Vehicle applications

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.