Nissan HR12DE

The Nissan HR12DE is a 1.2 l (1,198 cc, 73.11 cu-in) straight three, four-stroke naturally aspirated internal combustion gasoline engine from Nissan HR family.

The HR12DE has a cast aluminum engine block with four main bearings and aluminum DOHC (dual overhead camshaft) cylinder head with four valves per cylinder. This motor is equipped with Continuous Variable Valve Timing Control System (CVTCS), multi-point fuel injection system and electronic, distributor less type ignition system with individual ignition coil for each cylinder.

Cylinder bore is 78.0 mm (3.07 in) and piston stroke is 83.6 mm (3.29 in), compression ratio rating is 10.7:1 or 12:1. The Nissan HR12DE producted from 78.9 PS (58 KW; 77.8 HP) at 5,600 rpm to 84.3 PS (62 KW; 83.1 HP) at 6,000 rpm of horsepower and from 103 Nm (10.5 kg·m; 76.0 ft·lb) at 5,200 rpm to 110 Nm (11.2 kg·m; 81.2 ft·lb) at 4,000 rpm of torque.

The breakdown of the engine code is as follows:

• HR – Engine Family
• 12 – 1.2 Liter Displacement
• D – DOHC (Dual Overhead Camshafts)
• E – Electronic Port Fuel Injection

General information

Cylinder block

The HR12DE has an aluminum cylinder block with four bearing support system. Cylinders in the Nissan HR12DE 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 engine has cracking-processed connecting rods. Each piston is equipped with two compression and single oil control ring. The crankshaft and camshaft journals are finished with a polishing tape to produce a mirror-like finish.

Cylinder head

The cylinder head is made of strong, light aluminum alloy which gives it good cooling efficiency. The HR12DE has variable valve timing system (C-VTC) on the intake camshaft. Intake valves are 31.0 mm (1.22 in) in diameter, intake duration is 228°, and the exhaust valves are 25.5 mm (1.00 in), exhaust duration is 208°. The HR16DE 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 60°
• Step 3: Loosen all bolts completely
• Step 4: 40 Nm; 4.1 kg·m; 30 ft·lb
• Step 5: Turn all bolts 75°
• Step 6: Turn all bolts another 75°

Camshaft sprocket bolt

• 78.4 Nm; 8.0 kg·m; 58 ft-lb

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

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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.