In search of a larger but more fuel-efficient, lesser emissions engine for big trucks, Nissan responded with their innovations coming through the hoods of those heavy trucks. Inspired by their own VQ V6 engine family, Nissan moved to greater heights by creating a larger one in a V8 category. It was named and released under the family of the VK engines, and the engine we will discuss is the VK56DE.
So, with that being said, let us talk about the engine’s design, power, applications, issues, tuning potential, reliability, and many more.
What are Nissan VK56DE Engines?
The Nissan VK56DE, formerly called ZH engine, is a naturally-aspirated, 5.6 Liter, V8 gasoline engine from the Nissan VK family of engines. This engine was produced and made available for the North American market and was made in the United States in Nissan’s Dechard Plant in Tennessee. It first appeared in the 2004 Nissan Armada. The Nissan VK engines included smaller versions in 4.5 Liter VK45DE and 5.0 Liter VK50VE variants.
The VK56 engines retain most of the technological advancements originally crafted into the Nissan VK45, such as micro-finished camshafts and cranks journals, super quiet chain system, low-friction molybdenum-coated pistons, and epoxy resin-graphite coated piston skirts.
This engine also features a lightweight material aluminum block with a well-balanced five-bearing crankshaft and two aluminum cylinder heads with dual camshafts and four valves per cylinder. The VK56DE engine has an electronic throttle and ignition system, with each spark plug, has its own individual coils. The Variable Valve Timing control system (VVT-i) is absent on the earliest versions of the Nissan VK56DEs. In the later versions from 2007, Nissan integrated its CVTC (Continuously Variable Valve Timing Control) system on the intake camshafts.
VK56DE was also used in Nissan GT-R GT1 from Nissan’s motorsport line, Nismo.
Engine Specifications and Design:
- Production Run: 2003 – Present
- Cylinder Head Material: Aluminum
- Cylinder Block Material: Aluminum
- Configuration: V8
- Bore: 98 mm
- Stroke: 92 mm
- Valvetrain: DOHC with four valves per cylinder CVTCS
- Displacement: 5.6 L (5552 cc)
- Compression Ratio: 9.8
- Weight: 496 lbs.
- Max HP: 320 HP at 5,200 RPM
- Max Torque: 393 lb-ft at 3,400 RPM
The framework design of the VK56DE engine was based on Nissan’s same engine family in VK45DE, but with some minor differences in components as well as dimensions.
The engine’s cylinder block is made from aluminum with ductile iron cylinder liners and manufactured using gravity die casting (GDC); a five-bearing crankshaft system supports it. The engine bore is 98 mm and 92 mm stroke; the height of the block was increased by 12mm, resulting in an increased dimension to 232 mm, and connecting rods are 154.5 mm in length. Nissan VK56DE has one oil control ring and two compression rings.
In order to make a larger bore diameter, Nissan reduced the aluminum thickness between the bores from the previous 14.2 mm to 8.8 mm; the distance between each cylinder is increased from 14 mm to 19 mm. VK56DE engine has low-friction molybdenum-coated pistons, which allows the reduction of the compression ratio to 9.8. Its crankpin diameter is 54 mm, and its crankshaft journal diameter is 64 mm. As a result, this engine became the classical V8 with its torquey characteristic that is an ideal option for SUVs, pickups, and other big vehicles.
This 5.6 Liter V8 cylinder head has an excellent cooling efficiency due to its robust and light aluminum material. It acted with four valves per cylinder – two for both intake and exhaust valves. The earliest version of the VK56DE was not equipped with any valve timing control technology; however, the succeeding version ware equipped with Nissan’s Continuous Variable Valve Timing Control (CVTC) on the intake camshafts. This system enables the response of the variable valve timing to the corresponding engine RPM and throttle opening depending on different driving conditions. Reduced system friction and enhanced controls improve the response and optimize the characteristic of the torque.
The valvetrain is equipped with hydraulic lifters. To add to that, the engine features double overhead camshafts for each cylinder bank which are chain-driven, one for each head. The timing chain sends the rotational movement to both the intake and exhaust camshaft from the crankshaft. The intake manifold and headcovers are made for weight reduction hence its lighter composite material origins. The VK56DE is equipped with coil-on plugs, electric ignition, and an electronic throttle body, as well as the conventional multi-port injection system.
The engine’s intake valve diameter is 37 mm, and the exhaust valve diameter is 31.2 mm. The VK56DE engine uses special valve lifters instead of hydraulic lifters to adjust the valve clearance.
The VK56DE engine produces 320 HP at 4,900 RPM and up to 393 lb-ft of torque at 3,600 RPM.
Applications of the Nissan VK56DE Engine:
- 2004 – 2015 Nissan Armada
- 2004 – 2015 Nissan Titan
- 2004 – 2010 Infiniti QX56
- 2010 – 2016 Nissan Patrol
- 2008 – 2012 Nissan Pathfinder
- 2012 – 2016 Nissan NV2500 HD
- 2012 – 2016 Nissan NV3500 HD
- 2012 – 2016 Nissan NV Passenger
- 2009 – 2011 Nissan GT-R GT1
- 2013 – 2019 Nissan Altima, Supercars Championship
- 2015 LMP3 Racing
As we mentioned above, the VK56DE engine is used by Nismo for the FIA GT1 racing. For that application, the engine produces 600 HP and a staggering 479 lb-ft of torque.
This engine was introduced in Australia for its attempt to join the V8 Supercars Championship in 2013. The machine was then reduced in capacity from 5.6 L to 5.0 L for the engine to fit the regulations of the V8 Supercars. The bore is larger at 102.69 mm and a shorter stroke of 75 mm. It will eventually fall in the hoods of the Nissan Altima of the V8 Supercars “Car of the Future” specification, pushing a championship run from 2013 onwards.
In 2016, the VK56DE production was discontinued, and Nissan completely replaced these engines with a new modified version – the VK56VD. This engine is not unique to the public as it was already introduced in 2010, powering the M56 premium sport luxury sedan.
This VK56VD is a 32 valve, double overhead camshaft, 5.6 Liter V8, which was developed to saturate the growing demand for improved performance laced to a better fuel economy and cleaner emissions. This engine features Direct Injection Gas (DIG) technology – a direct fuel injection system where high-pressure direct injectors inject fuel directly into the cylinders, requiring a new cylinder head design. Added to that, this also allows the engine to control the injection process more accurately, which results in a better fuel economy, improved throttle performance, and emissions performance by improving combustion stability and reducing the engine knock.
Contrary to the early generations of the VK56DE engines, this engine is integrated with the Continuous Variable Valve Event and Lift System (VVEL) on both the intake and exhaust sides. It has an increased compression ratio of 11.2 through the installation of a new piston design. The cooling system is changed from the traditional thermostat to a Multi Control Valve system.
The rated output of the engine varies on its vehicle application.
Applications of the VK56VD Engine:
- 2010 – Present Nissan Patrol 400 HP and 413 lb-ft torque
- 2016 – Present Nissan Patrol Nismo 428 HP and 417 lb-ft torque
- 2011 – Present Infiniti QX80 400 HP and 413 lb-ft torque
- 2011 – 2012 Infiniti M56 420 HP and 417 lb-ft torque
- 2014 – 2019 Infiniti Q70 420 – 436 HP and 417 lb-ft torque
- 2017 – Present Nissan NV2500 HD 375 HP and 387 lb-ft torque
- 2017 – Present Nissan NV3500 HD 375 HP and 387 lb-ft torque
- 2017 – Present Nissan NV Passenger 375 HP and 387 lb-ft torque
- 2017 – Present Nissan Titan 400 HP and 413 lb-ft torque
- 2017 – Present Nissan Armada 390 HP and 395 lb-ft torque
Engine Tuning, Upgrades, and Modifications
I bet that you already know that this engine is incredibly powerful. Its 5.6 Liter capacity is an indication of how enormous the power output of this engine. Well, if you still find yourself looking for more power, you can gain more horsepower for this engine. The first thing is you need to buy new valve springs, cold air intake, JWT 256/256 camshafts, 90 mm throttle body, 3-inch performance exhaust system, and headers. Adjust the ECU, and you can gain about 350 HP.
If you decided to add a supercharger kit, use the Stillen supercharger kit, which can give you around 450 HP.
Problems Surrounding Nissan VK56DE Engine:
Like all other engines, the Nissan VK56DE is not a perfect engine at all, and no machine is. Though it offers the fine balance between longevity and, aggressiveness, and reliability, we cannot change the fact that even the most reliable engines still pose some problems that will eventually occur as the engine starts to age. These issues are addressed so that you will be aware of the problems that might arise in the machine, so you know what to expect.
First is the issue on the timing chain. This issue might not be typical and the least likely you would expect, but it is still an issue that needs to be told. The primary cause might be the stretching of the timing chain. The case can cause severe damage, especially on the tensioners, which escalates the problem more.
You will notice noise in the engine or squeaky rattling sound when chains began to stretch; usually, it is the indicator and warning sign that the timing chain will be out soon. Please note that if the timing jumps, even a few teeth, it results in a serious number of symptoms.
You will have to replace the timing chain with the high-pressure fuel pump to avoid further implications.
Next is the loss of power or rough idling. This issue is identical like on those of VQ35 engines; this trouble happens due to a worn-out catalytic converter, which we can blame and point our finger to the usage of low fuel quality. When the engine absorbs the dust, it grinds the cylinder walls that cause abrasion, reaching the oil system and spreading it all over the engine. Unfortunately, the only way out to solve this is to buy a new VK56DE machine which is not a good idea for those who have shallow pockets. But, you can solve it by installing a high flow catalytic converter plus an ECU reflash.
The third is the loss of dynamics and power. Once this issue happened, the symptoms make progress also and can only mean one thing – the dysfunction of the fuel pump. Check it, and if the situation of the fuel pump is deteriorating, you need to purchase a fresh fuel pump.
There are also some problems regarding the exhaust manifold, also known as exhaust headers and headers. It is one of the most common issues for this engine, especially on the Titan models. The main reason for manifold cracking is its poor design. As science dictates, metals expand when subjected to an increased temperature, and the exhaust manifold is a camper in that temperature region and even on extreme levels. That constant heating and cooling wear down the metal and fatigues the manifold that causes crack and the leaking of exhaust gases.
Another VK56DE issue that needs to be addressed is the unreliable AC condenser cooling fan, which haunted the early VK56DE engines, leading to overheating due to jamming. Furthermore, it is equally vital to wash the radiator annually as the clean ones have less likelihood of overheating as well as the replacement of fuel pumps after 60,000 miles, at minimum.
To avoid these unnecessary issues, use high-quality engine oil and fuel.
Nissan VK56DE engine is a powerhouse considering its colossal capacity. Apart from its enormous profile, this engine is pretty above average in its reliability and longevity, which relatively lasts up to 250,000 miles when properly maintained. However, its earlier models were haunted by some problems such as the unreliable AC condenser radiator cooling fan; and a couple of few design flaws such as the timing chains, faulty exhaust manifold, and even catalytic converters. After all, engine life depends on the level of care, with a little bit of luck, to the machine. This VK56DE engine, a collective product of the previous engine made by Nissan, is truly a craft.
I hope that this simple discussion helped you understand the VK56DE’s engine design, applications, power output, tuning potential, issues, reliability, and overall impact on the industry and community.