Nissan VQ35HR

The Nissan VQ35HR is a 3.5 l (3,498 cc, 213.45 cu.in.) natural aspirated V6 60° 4-stroke gasoline engine from Nissan VQ-family. The engine is producted on Nissan’s Iwaki Plant in Fukushima Prefecture. The VQ35HR engine was honored by Ward’s 10 Best Engines list in 2007.

The VQ35HR engine is a re-engineered version of earlier VQ35DE engine. The VQ35HR features a lightweight aluminum block with a fully balanced four-bearings crankshaft and two aluminum heads with two camshafts (DOHC) and four valves per cylinder. The Nissan VQ35HR engine is equipped with CVTC system on intake valves, e-VTC on exhaust valves and NDIS (Nissan Direct Ignition System) with individual coils on each spark plug. The redline is 7,500 rpm.

Compression ratio rating is 10.6:1. Cylinder bore and piston stroke is 95.5 mm (3.76 in) and 81.4 mm (3.20 in), respectively. It produces from 297 HP (221 kW) at 6,800 rpm on a version of Infiniti EX37 up to 313 HP (232 kW) at 6.800 rpm. On some hybrid vehicle models this engine produces up to 360 HP (268 kW), but only in combined with an electric motor. The maximum torque is 358 Nm (36.50 kg·m, 264.0 lb·ft) at 4,800 rpm.

The breakdown of the engine code is as follows:

• VQ – Engine Family
• 35 – 3.5 Liter Displacement
• HR – High Response and High Revolution

General information

Cylinder block

The VQ35HR has an aluminum block with a four-bearings crankshaft supported system. The VQ35HR engine employs a stiff ladder frame to support the crankshaft.

To support higher engine speeds, Nissan applied a friction-reducing solution: lengthening the connecting rods. Raising the cylinder block deck height permits a 7.6 mm (0.3 in) increase in connecting rod length. The new VQ engine uses asymmetrical piston skirts to reduce friction. The connecting rod bolt diameter has been increased from 8 mm (0.31) to 9 mm (0.35 in) to gain about 25% in strength.

During high-rev operation, the crankshaft may flex and twist, causing noise, vibration and, potentially, damage to the journals. To deal with this issue, the new VQ35 engine uses a larger journal diameter and a stiffer crankshaft. The crankshaft journal diameter has been increased from 60 mm (2.36 in) on DE-engine to 65 mm (2.55 in) on HR-version, the crankpin diameter has also been increased from 52 mm (2.04 in) to 54 mm (2.12), respectively.

The cylinder bore is 95.5 mm (3.760 in), piston stroke is 81.4 (3.205 in) mm and compression ratio rating is 10.6:1. The Nissan VQ35HR motor has two compression and one oil control rings. The connecting rod’s length is 144 mm (5.66 in)

Cylinder head

The cylinder head is made of strong, light aluminum alloy which gives it good cooling efficiency. The engine is equipped with hydraulically actuated CVTC (Continuous Variable Valve Timing Control) for intake cams and electromagnetic Valve Timing Control (e-VTC) on the exhaust side.

The camshafts are driven by single primary and two secondary chains. The primary timing chain transmits the rotational movement from the crankshaft to the intake camshafts, the secondary chains connects intake and exhaust sprocket on each head respectively.

The intake valve diameter decreased from 37.0 mm (1.45 in) on DE-version to 36.6 mm (1.44 in) on HR-engine and the exhaust valve diameter decreased from 31.2 mm (1.22 in) to 30.2 mm (1.18 in), respectively. The VQ35HR motor does not have hydraulic lifters, so special valve lifters are used to adjust the valve clearance.

To reduce air intake resistance, the new VQ engine adopts asymmetrical twin intake configuration. To support high-rev, high-power engine performance, the VQ35HR engine adopts a straight intake port design.

Head tightening procedure and torque specs:

• Step 1: 105 Nm; 11.0 kg·m; 77 ft·lb
• Step 2: Loosen all bolts completely
• Step 3: 40.0 kg·m; 4.1 kg·m; 30 ft·lb
• Step 4: Turn all bolts 95°
• Step 5: Turn all bolts another 95°

Camshaft sprocket bolts

• 103 Nm; 11.0 kg·m; 76 ft·lb

Problems and malfunctions

The Nissan VQ35HR is reliable and durable, but sometimes the following problem can happen:

• High oil consumption. The VQ37VHR has a catalytic converter and they are very sensitive to the fuel quality. They produce ceramic dust, which damaging the cylinders sleeve and piston rings. As a result, the engine has low compression, high fuel, and oil consumption. Such an engine requires repair or replacement.

  To prevent this problem, you need to change the upper catalytic converters for high flow catalytic converter. It will decrease ecological standard, but this problem will not happen.

The engine has three timing chains, 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 Nissan VQ35HR motor life expectancy is 200,000 miles of mileage (300,000 km) or more.

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 – 0.34 mm (0.013 in)]

Valve lifters are available in 27 sizes to range from 7.88 mm (0.3102 in) to 8.40 mm (0.3307 in), in steps of 0.02 mm (0.0008 in).

Example (exhaust valve):
R = 7.90 mm
M = 0.52 mm
N = 7.90 + (0.52 – 0.34) = 8.08 mm, so we need a valve lifter with identification mark 808P.

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.