Nissan VH45DE Specifications
| Engine Model: Nissan VH45DE |
| Engine Type: 4-cycle 8-cylinder DOHC 32-valve VTC liquid-cooled gasoline |
| Total Displacement: 274.3 cu.in (4.49 L) |
| Rated Engine Power: 278-285 Hp (207-213 kW) at 6000 rpm |
| Fuel System Type: Multi-point electronic fuel injection |
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The Nissan VH45DE is a 4.5-liter, naturally aspirated
V8 engine that served as Nissan’s flagship powerplant during the early 1990s,
representing the pinnacle of the company’s engineering capability in the luxury
and performance segments. Developed as the premier engine for the Infiniti Q45
and its Japanese domestic market counterpart, the Nissan President, the VH45DE
combined advanced technology with an overbuilt internal architecture that has
since earned it a legendary reputation among enthusiasts for durability and
high-rpm capability.
The engine features a 90-degree V8 configuration with dual overhead camshafts
(DOHC), 32 valves, and variable valve timing control (VTC) on the intake
camshafts. The aluminum cylinder block and cylinder heads contribute to reduced
weight while maintaining structural rigidity through a deep-skirt block design.
The VH45DE is distinguished by its forged steel crankshaft, forged connecting
rods, and six-bolt main bearing caps - components more commonly found in racing
engines than in production luxury sedans.
The engine’s oversquare design, with a bore of 93.0 mm and a stroke of 82.7 mm,
enables a high 6,900 rpm redline while maintaining the torque characteristics
expected of a luxury V8. Early versions produced from 1990 to 1995 are
particularly sought after for their metal timing chain guides, while later
variants utilized plastic guides that introduced a known failure point. The
VH45DE also served as the foundation for the Infiniti Indy 3.5-liter racing
engine used in the Dallara IR series, underscoring the inherent strength of its
architecture.
The VH45DE is a four-stroke, water-cooled gasoline engine operating on the
spark-ignition principle. The engine architecture is a 90-degree V8
configuration with a total displacement of 4,494 cc (274.3 cu.in), derived from
a bore of 93.0 mm (3.66 in) and a stroke of 82.7 mm (3.26 in). This oversquare
design, with bore exceeding stroke, promotes higher engine speeds and increased
volumetric efficiency at elevated rpm, a characteristic suited to the engine’s
high-revving nature. The compression ratio is set at 10.2:1, a value that
balances power output with fuel efficiency and allows operation on premium
unleaded fuel.
The valvetrain utilizes dual overhead camshafts (DOHC) per cylinder bank, with
four valves per cylinder for a total of 32 valves. The intake camshafts are
equipped with variable timing control (VTC), a hydraulic system that adjusts
intake camshaft timing relative to the crankshaft to optimize valve overlap
across the engine speed range. The camshafts are driven by a double-row roller
timing chain, a robust system designed for the engine’s service life. The firing
order for this V8 engine is 1-8-7-3-6-5-4-2, ensuring even firing intervals of
90 degrees of crankshaft rotation. The redline is set at 6,900 rpm, with maximum
power and torque peaks occurring within the upper portion of the rev range.
Performance outputs reflect the engine’s luxury and performance positioning.
Maximum power ranges from 207 kW (278 hp) to 213 kW (285 hp) at 6,000 rpm
depending on market and emission equipment. Maximum torque ranges from 396 Nm
(292 lb-ft) to 399 Nm (294 lb-ft) at 4,000 rpm. The torque curve is
characterized by a broad plateau that provides strong acceleration across the
operating range. The idle speed is set at approximately 650 rpm when the engine
is at operating temperature. The engine requires premium unleaded gasoline with
a minimum octane rating of 91 RON to achieve the specified performance.
The cylinder block is manufactured from aluminum alloy
with a deep-skirt design that extends below the crankshaft centerline, providing
exceptional structural rigidity for a V8 engine of this displacement. The
deep-skirt construction contributes to noise, vibration, and harshness reduction
while supporting the high-rpm capability of the engine. The cylinder bores are
cast directly into the aluminum structure and are finished with a plateau honing
process that optimizes oil retention and piston ring sealing. The bores
incorporate cast-in-place iron liners or a sprayed-on iron bore coating
depending on the production period, providing the wear resistance required for
the forged aluminum pistons.
The main bearing caps are manufactured from high-strength nodular cast iron and
are secured with six bolts per cap - two vertical bolts on each side and two
cross-bolts - a six-bolt main bearing design that provides exceptional
crankshaft support under high-rpm and high-load conditions. This level of main
bearing reinforcement is unusual for a production luxury sedan engine and
reflects the VH45DE’s overbuilt engineering philosophy. The crankshaft is
manufactured from forged steel, a material choice that provides superior
strength and fatigue resistance compared to cast iron crankshafts. The cylinder
block incorporates the timing chain housing at the front, including the mounting
points for the double-row timing chain, hydraulic tensioners, and chain guides.
Each cylinder bank is served by a separate aluminum
alloy cylinder head, a design that reduces manufacturing complexity and
facilitates assembly. Each cylinder head houses dual overhead camshafts - one
intake and one exhaust - supported by five bearing journals per camshaft. The
intake camshaft incorporates the variable timing control (VTC) mechanism, a
hydraulic actuator that rotates the intake camshaft relative to the drive
sprocket to advance or retard valve timing based on engine speed and load.
Each cylinder utilizes four valves - two intake and two exhaust - arranged in a
pent-roof combustion chamber design that optimizes breathing efficiency and
swirl characteristics. The valves are actuated by bucket-type tappets with shims
for valve clearance adjustment. The intake valves have a diameter of 34.0 mm
(1.34 in), while the exhaust valves have a diameter of 31.0 mm (1.22 in).
The exhaust valves are sodium-filled, with hollow stems partially filled with
sodium that liquefies at operating temperature and transfers heat from the valve
head to the stem and into the valve guide, providing superior heat dissipation
under high-rpm operation. The valve seat inserts are manufactured from sintered
metal alloys selected for heat resistance and wear durability. The cylinder head
gaskets are multi-layer steel (MLS) designs, providing robust sealing between
the aluminum block and aluminum heads.
The VH45DE is equipped with a sequential multi-point
electronic fuel injection (SMPFI) system. Fuel is delivered from an in-tank pump
to dual fuel rails mounted on each cylinder head, distributing fuel to eight
individually controlled injectors, each mounted in the intake port directly
upstream of the intake valve. The sequential injection system fires each
injector in synchronization with the intake stroke of its corresponding
cylinder, optimizing fuel atomization and mixture preparation. The fuel pressure
is regulated by a pressure regulator mounted on the fuel rail, maintaining a
constant pressure differential across the injectors relative to intake manifold
vacuum.
The injectors are electrically actuated and are capable of precise fuel metering
based on signals from the engine control unit (ECU). The ECU monitors crankshaft
position, camshaft position, mass air flow, intake air temperature, coolant
temperature, throttle position, and exhaust oxygen content to calculate
injection duration. The fuel system operates at a pressure of approximately 3.0
bar (44 psi) to 3.5 bar (51 psi) depending on engine load and operating
conditions.
The lubrication system is a forced-feed, full-flow
filtration design utilizing a gear-type oil pump mounted at the front of the
engine and driven by the crankshaft. The oil pump is integrated into the timing
chain housing and draws lubricant from the sump through a strainer, delivering
it to the main oil gallery. The system maintains stable oil pressure across the
operating range, with a pressure relief valve calibrated to open at
approximately 4.5 bar (65 psi).
A liquid-to-liquid oil cooler is integrated into the engine coolant circuit to
maintain oil viscosity under sustained high-load or high-speed conditions. The
engine employs a full-flow spin-on oil filter mounted on the engine block. The
oil pan is constructed from aluminum and has a capacity of approximately 5.5
liters (5.8 US qt) to 6.0 liters (6.3 US qt) depending on the variant. The
engine requires 5W-30, 10W-30, or 10W-40 engine oil meeting API SG or higher
specification.
The cooling system is a pressurized, water-cooled
design utilizing a centrifugal water pump driven by the timing chain. The system
maintains engine operating temperature within a range of 80°C to 95°C (176°F to
203°F) under normal conditions. The coolant circuit includes a thermostatic
bypass that facilitates rapid warm-up and reduces internal friction during cold
starts.
The water pump is mounted on the front of the engine block and is serviced in
conjunction with timing chain replacement due to its location behind the timing
chain covers. The aluminum cylinder block and cylinder heads provide superior
thermal conductivity, allowing efficient heat transfer from the combustion
chambers to the coolant. A cross-flow radiator with dual electric cooling fans
supplements the system at low vehicle speeds and during idle conditions. The
total coolant capacity for the engine and cooling system is 9.0 liters (9.5 US
qt) to 10.0 liters (10.6 US qt).
Intake System: The intake system incorporates a
composite plastic intake manifold with variable intake runner lengths. The
manifold features a dual-stage system that opens secondary runners at higher
engine speeds to optimize torque production across the operating range. The
throttle body is electronically controlled on later variants for precise idle
speed management and integration with the vehicle’s traction control systems.
Engine Management: The engine is controlled by a Nissan engine control unit
(ECU) that monitors crankshaft position, camshaft position, mass air flow,
intake air temperature, coolant temperature, throttle position, and exhaust
oxygen content. The ECU controls fuel injection duration, ignition timing,
variable intake manifold actuation, and variable valve timing control on the
intake camshafts.
Ignition System: The ignition system is a distributorless, direct-fire design
utilizing individual ignition coils mounted directly over each spark plug in a
coil-on-plug arrangement. The spark plugs are platinum-tipped for extended
service life. The ignition timing is controlled by the ECU and is not
adjustable.
Exhaust System: The exhaust system incorporates a stainless steel exhaust
manifold on each cylinder bank, merging into a dual exhaust system with
underfloor catalytic converters. The system includes oxygen sensors positioned
before and after each converter for closed-loop fuel control.
The engine length, measured from the timing chain cover
to the flywheel housing face, is 700 mm (27.6 in). The width, measured across
the cylinder banks at the widest point including the intake manifold and exhaust
manifolds, is 750 mm (29.5 in). The height, measured from the oil pan bottom to
the top of the intake manifold or cylinder head covers, is 700 mm (27.6 in).
The dry weight (without fluids, starter, alternator, or air conditioning
compressor) is 200 kg (441 lb). The fully dressed weight for a vehicle
application, including all accessories, wiring harness, and fluids, is 230 kg
(507 lb).
The service life of the VH45DE under proper operating
conditions is engineered to exceed 400,000 km (250,000 mi) with regular
maintenance. Oil change intervals are recommended at 5,000 km (3,100 mi) to
7,500 km (4,700 mi) depending on operating conditions and oil quality. The
engine requires engine oil meeting API SG or higher specification in viscosities
of 5W-30, 10W-30, or 10W-40.
The timing chain system requires inspection at 150,000 km (93,000 mi) intervals,
with particular attention to the chain guides. Early engines (1990-1995) utilize
metal chain guides that exhibit excellent durability, while later engines
(1994-1996) employ plastic guides that may become brittle and fail with age.
Replacement of the timing chain, tensioners, and guides is recommended if wear
or guide deterioration is detected. Valve clearance inspection is mandated every
100,000 km (62,000 mi), with adjustment performed using shims as required.
Replacement of the spark plugs is required every 100,000 km (62,000 mi) for
platinum-tipped plugs. Replacement of the fuel filter is recommended every
40,000 km (25,000 mi). The air cleaner element requires replacement every 40,000
km (25,000 mi), with more frequent servicing in dusty environments. The coolant
must be replaced every 4 years or 80,000 km (50,000 mi), using a phosphate-free,
long-life coolant formulation. The accessory drive belt requires inspection at
each service interval, with replacement recommended every 60,000 km (37,000 mi)
or sooner if cracking or wear is evident.
The cylinder head bolts follow a multi-stage angular
torque procedure. The M12 cylinder head bolts receive an initial torque of 40 Nm
(30 lb-ft), followed by a 90-degree angle, and a final 90-degree angle in a
specified sequence. The main bearing cap bolts are torqued to 60 Nm (44 lb-ft)
plus a 60-degree angle for the vertical bolts, with the cross-bolts receiving 35
Nm (26 lb-ft) plus a 45-degree angle.
The connecting rod bolts are tightened to 25 Nm (18 lb-ft) plus a 90-degree
angle. The flywheel-to-crankshaft bolts receive a torque of 100 Nm (74 lb-ft)
plus a 60-degree angle. The camshaft bearing cap bolts are torqued to 12 Nm (9
lb-ft). The spark plugs are torqued to 20 Nm (15 lb-ft). The intake manifold
bolts are torqued to 20 Nm (15 lb-ft). The exhaust manifold bolts are torqued to
35 Nm (26 lb-ft). The timing chain tensioner bolts are torqued to 10 Nm (7
lb-ft).
The VH45DE served as the flagship engine for Nissan’s
luxury sedan offerings throughout the 1990s. The primary application was the
Infiniti Q45 (G50 generation, produced from 1990 to 1996), where the engine
provided the power and refinement expected of Nissan’s luxury division in North
American and export markets.
In the Japanese domestic market, the engine powered the Nissan President (G50
generation, produced from 1990 to 2002), a limousine-style luxury sedan that
competed with the Toyota Century and other high-end offerings. The President
retained the VH45DE after the Q45 transitioned to the smaller VH41DE and later
VK series engines, making it the longest-serving application of this powerplant.
Beyond production vehicles, the VH45DE’s robust internal architecture made it
the foundation for the Infiniti Indy racing engine. The Dallara IR-7, IR-8, and
IR-9 chassis utilized a 3.5-liter displacement version of the VH45DE for the
Infiniti Indy program in the late 1990s, demonstrating the inherent strength and
design capability of the engine’s architecture in a competitive racing
environment.
The VH45DE remains highly regarded among automotive enthusiasts for its
overbuilt construction, high-rpm capability, and potential for performance
modifications. Its forged internals, six-bolt main bearing caps, and
sodium-filled exhaust valves continue to make it a sought-after engine for
custom vehicle builds and engine swaps decades after its production ceased.
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