VK56DE Engine

The Nissan VK engine (previously called the ZH) is a V8 piston motor, featuring an aluminum dual overhead camshaft with four valves.

Actually, VK56 was built on the framework of the brand’s VQ V6 motor but not VH V8, applied for Q45/Cima vehicles. Among the main differences are a variable intake manifold of polymer, restyled heads and a better drive of the wire throttle chamber. Intake manifold routes air in different directions depending on the engine speed. It helps to enhance low-end torque or high-end horsepower.

 

Nissan VK56DE engine specs

The breakdown of the engine code is as follows:

  • VK – Engine Family
  • 56 – 5.6 Liter Displacement
  • D – DOHC (Dual Overhead Camshafts)
  • E – Multi Point Fuel Injection

Manufacture of VK56DE was launched in 2003 as the power unit for the Nissan Armada car, sold in the United States. Being an American product, this 5.6L motor has more compact modifications, VK45DE and VK50VE.

Though VK56DE has much in common with VK45DE, they differ in some aspects. Thus, the height of the cylinder block rose to 232 mm while the bore became 98 mm (in comparison with 93 mm in the original version). The motor keeps connecting rods of 154.2 mm along with fresh pistons able to diminish the compression index to 9.8. Consequently, the engine turned out to be more classically torquey V8 and became a great option for pickups, SUVs and some other big vehicles.

With aluminum cylinder heads, featuring 4 valves per cylinder and 2 camshafts, this motor keeps an intake camshaft with Continuous Variable Valve Timing Control system (shortly CVTCS). While the engine is provided with hydraulic lifters, timing chains remain its blind side.

VK56VD is another modification of the motor. It features more advanced technologies, using direct injection fuel system, variable valve timing system on two camshafts along with Variable Valve Event and Lift system.

Manufacturer Decherd Plant
Also called Nissan VK56
Production 2003-present
Cylinder block alloy Aluminum
Configuration V8
Valvetrain DOHC
4 valves per cylinder
Piston stroke, mm (inch) 92 (3.62)
Cylinder bore, mm (inch) 98 (3.86)
Compression ratio 9.8 (VK56DE)
10.8 (VK56VD)
Displacement 5552 cc (338.8 cu in)
Power output 224 kW (305 HP) at 4,900 rpm
239 kW (325 HP) at 5,200 rpm
298 kW (405 HP) at 5,800 rpm
300 kW (408 HP) at 6,000 rpm
Torque output 522 Nm (385 lb·ft) at 3,500 rpm
533 Nm (393 lb·ft) at 3,400 rpm
560 Nm (413 lb·ft) at 4,000 rpm
550 Nm (406 lb·ft) at 4,400 rpm
Redline 6,000
HP per liter 54.9
58.5
72.9
73.5
Fuel type Gasoline
Weight, kg (lbs) 227 (500)
Fuel consumption, L/100 km (mpg)
-City
-Highway
-Combined
for Infiniti QX80
20.6 (11)
11.0 (21)
14.5 (16)
Turbocharger  Naturally aspirated
Oil consumption , L/1000 km
(qt. per miles)
up to 1.0
(1 qt. per 600 miles)
Recommended engine oil 5W-30
5W-40
10W-30
10W-40
Engine oil capacity, L (qt.) 6.5 (6.9)
Oil change interval, km (miles) 5,000-10,000
(3,000-6,000)
Normal engine operating temperature, °C (F)
Engine lifespan, km (miles)
-Official information
-Real

400,000+ (250,000)
Tuning, HP
-Max HP
-No life span loss
400+



Applications

  • Infiniti M56/Q70
  • Infiniti QX56/QX80
  • Nissan Pathfinder
  • Nissan Patrol
  • Nissan Armada
  • Nissan NV
  • Nissan Titan

VK56DE Cylinder Head

Durable but light aluminum alloy, the cylinder head is made of, provides it with great cooling efficiency. While the original motor lacked valve timing control system, the intake camshafts of its new variation feature Continuous Variable Valve Timing Control, which permits variable valve timing to respond to motor redline and throttle opening.

Meanwhile, the advanced control and the lowered system friction contribute to better reaction and advanced torque specifications. Two chains control the camshafts.

The timing chain conveys the rotating movement from the crankshaft to intake and exhaust camshafts.

Diameter of the intake valve is 37.0 mm (1.45 inches) while the exhaust valve is 31.2 mm (1.22 inches). The intake duration for the motor without CVTC is 230 degrees and 232 degrees for the one featuring it. The exhaust duration for CVTC is 244 degrees while it’s 232 degrees for the engine without it. VK56DE isn’t equipped with hydraulic tappets and, consequently, the valve clearance is regulated by specific valve lifters.

Block head alloy Aluminum
Valve Arrangement: DOHC, chain drive
Cylinder head height: 126.3 mm (4.97 in)
Valves: 32 (4 valves per cylinder)
Intake valve timing: W/o CVTC: 230°
With CVTC: 232°
Exhaust valve timing: W/o CVTC: 232°
With CVTC: 244°
Valve head diameter: INTAKE 37.0-37.3 mm (1.457-1.469 in)
EXHAUST 31.2-31.5 mm (1.228-1.240 in)
Valve length: INTAKE 96.21-96.71 mm (3.7878-3.8075 in)
EXHAUST 93.74-94.24 mm (3.6905-3.7102 in)
Valve stem diameter: INTAKE 5.965-5.980 mm (0.2348-0.2354 in)
EXHAUST 5.965-5.970 mm (0.2344-0.2350 in)
Valve spring free length: INTAKE 50.58 mm (1.9913 in)
EXHAUST 50.58 mm (1.9913 in)
Camshaft cam height: INTAKE 44.465-44.655 mm (1.7506-1.7581 in)
EXHAUST 44.465-44.655 mm (1.7506-1.7581 in)
Camshaft journal diameter: 25.953-25.970 mm (1.0218-1.0224 in)

VK56DE Problems and reliability

  1. Motor uproar. It usually caused by the stretched timing chain. It’s important to take care of it as such a trouble may emerge even if the vehicle hasn’t run too much. If you face this problem, replace the timing chain plus high pressure fuel pump in order to avoid the emergence of any malfunctions in the future. Be ready that this procedure will be pretty pricy as in order to replace the timing chain, it’s necessary to disassemble the car’s front.
  2. Rough idle and decreased output. Like in VQ35, this trouble is caused by worn out catalytic converters due to fuel of low quality. Consequently, the motor absorbs the dust, which abrades the cylinder walls and later reaches the oil system before spreading all over the motor. Bad news: the only way out is to acquire a brand new engine. However, in countries, which have poor quality gasoline, the problem is resolved by mounting high flow catalytic converter plus ECU reflash.
  3. Decreased efficiency and bad dynamics. The basic reason is the dysfunction of the fuel pump. And if the situation deteriorates, it’s the right time to buy a fresh pump.

The first VK56DE motors featured unreliable AC condenser radiator cooling fan, which could jam and lead to overheating. Moreover, it’s crucial to wash the radiator every year as the clean one is less prone to overheating, which leads to cylinder head gaskets destruction. Furthermore, it’s advisable to replace the high-pressure fuel pump after 50,000-60,000 miles (80,000-90,000 kilometers) are run as it’s not very durable.

You may also face the deformation of filter bodies, which result in dust and other small litter getting stuck in the motor and causing its malfunction.

Having faced with the erratic idling speed trouble, cleaning of the throttle body may help to get rid of it. It’s advisable to do that every 60,000-70,000 miles (100,000-120,000 kilometers). Be ready that radiator leakage may happen after 120,000 miles (200,000 kilometers) are run.

In order to avoid these troubles, try to use the fuel and engine oil only of high quality. Moreover, it’s advisable to replace oil on a regular basis and serve the vehicle on time.



Written by Dan Hoffman

Dan Hoffman

Dan is a co-founder of Engineswork. He knows everything about internal combustion engines. Ask your questions in comments down below this article – he will be glad to help you anytime.

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