|This article needs additional citations for verification. (December 2009)|
|Cylinder block alloy||Aluminum|
|Cylinder head alloy||Aluminum|
|Fuel system||Fuel injection|
|Predecessor||Nissan Y engine|
|Successor||Nissan VK engine|
The VH series consists of 4.1 and 4.5 liter engines built from 1989-2001 by the Nissan Motor Corporation. The design consists of a 90 degree V8 with an aluminum cylinder block that features a closed upper deck and a deep skirt. The cylinder heads are also aluminum with a DOHC 4-valve design and pentroof combustion chambers. The production blocks and production head castings were used successfully in various forms of racing including the IRL.
The VH45DE is a 4.5 liter V8 developed by Nissan for use in the Infiniti Q45 sport luxury sedan (G50 platform) which was released in November 1989. The engine was also used in the Japanese market Nissan President limousine (JG50 platform) which debuted in late 1990. The VH45DE generates 278 hp (207 kW) at 6000 rpm and 292 lb·ft (396 N·m) at 4000 rpm with a redline of 6900 rpm.
Some of the pertinent features of the VH45DE are:
- Forged steel crankshaft.
- Forged steel connecting rods.
- 6 Bolt main bearing caps with studs.
- Full-length main bearing girdle.
- Lightweight, floating pistons with molybdenum coating.
- Sodium-filled exhaust valves.
- Cross-flow cooling system.
- Hydraulic lash adjusters.
- Single-row silent timing chain.
- Coil-on-plug ignition system.
- Lifter buckets ride directly on cams to reduce friction.
- Redline of 6900 rpm.
- Compression ratio of 10.2 to 1.
- Bore of 93 mm and stroke of 82.7 mm.
- Dimensions: 890 mm(L) x 740 mm(W) x 725 mm(H).
The 4.5 L VH45DE featured variable valve timing, also known as VTC, from 1990 until 1995. This was due to the "Gentleman's Agreement", requiring all imports to produce no more than 280 hp. Nissan got around this by publishing the hp rating without VTC, meaning its actual power rating is closer to 310 hp and 330 lb·ft. of torque. Due to tightening emissions regulations in the US market, the VTC feature was dropped from the 1996 Infiniti Q45. In the following year, the VH45DE was no longer available in any US market vehicles. The engine continued on in the Japanese market until 2002 in the Nissan President limousine.
VH45DEs made before 1994 used plastic timing chain guides, and over time these have been known to fail. This results in a noisy valvetrain and parts of the plastic guides can end up in the sump and oil pickup, resulting in engine damage. Nissan changed to metal backed chain guides from 1994 onwards.
This engine was used in the following vehicle(s):
- 1990-1996 Infiniti Q45, 278 hp (207 kW), 294 lb·ft (399 N·m)
- 1991-2002 Nissan President, 278 hp (207 kW), 294 lb·ft (399 N·m)
The VH41DE is a 4.1 liter V8 that was based on the VH45DE. The bore of 93 mm remained but the stroke was shortened to 76 mm. Power output for the new engine was 268 hp (200 kW) at 5600 rpm and 278 lb·ft (377 N·m) at 4000 rpm.
The VH41DE also used a double row timing chain, compared to the VH45DE that used a single row timing chain. Its alternator is also located at the top of the engine which creates an overall narrower engine package which can be handy in engine conversions where it may otherwise foul on the chassis rails.
The 4.1 L VH41DE was used in the following vehicles:
- 1997-2001 Infiniti Q45 266 hp (198 kW), 278 lb-ft (370 N-m)
- 1992-1996 Nissan Leopard, 270 PS (199 kW), 278 lb-ft (370 N-m)
- 1991-1996 Nissan Cima Y32, 266 hp (198 kW), 278 lb-ft (370 N-m)
- 1996-2001 Nissan Cima Y33, 270 PS (199 kW), 278 lb-ft (376 N-m)