Jaguar AJ6 engine

From Wikipedia, the free encyclopedia

Jaguar AJ6
Manufacturer	Jaguar Cars
Production	1984–1996
Predecessor	Jaguar XK6
Successor	Jaguar AJ-V6 Jaguar AJ-V8
Class	DOHC I6
Engine	3.6 L (3590 cc/219 in³) 2.9 L (2919 cc/178 in³) 3.2 L (3239 cc/197 in³) 4.0 L (3980 cc/242 in³)

The AJ6 (Advanced Jaguar 6-cylinder), and the similar AJ16, was an inline-6 piston engine used by Jaguar in the 1980s and 1990s. It was designed to replace the much-loved Jaguar XK6 engine, and was introduced in 1984. The AJ6 was only the third engine ever designed by the company. The AJ6 was replaced in 1996 with the Ford Duratec-derived Jaguar AJ-V6 engine.

Jaguar had considered cutting the V12 in half to build a V6, or possibly a V8, but chose instead to develop a new inline-6. The cylinders are inclined, as in a slant-6, by 22 degrees. It is uses an aluminum block to reduce weight, and has an optional DOHC head for higher efficiency and power.

1 AJ6
2 AJ16
- 2.1 4.0 / 3.2 (1994-1997)
- 2.2 AJ16S
3 See also

[edit] AJ6

The original engines were the DOHC 3.6 and the SOHC 2.9. The DOHC 3.6 was revised and enlarged to 4.0 in 1990. It is still essentially an "AJ6", however. This was, as per usual, offered for the XJ-S before it was built into the XJ40 saloon.

[edit] 3.6

The 3.6 was the first AJ6 engine, debuting in 1983 on the XJS. It had DOHC 4-valve heads with a 91 mm bore and 92 mm stroke. Power was 165 kW (221 hp) with 325 Nm (240 Lb-Ft) of torque. Power was reduced to 201 hp for versions having catalytic exahust system. Early versions of the 3.6L AJ6 as used in the 1984 - 1987 XJS cars had a conventional distributor type of ignition system with electronics within the distributor body. This early AJ6 ignition system is nearly identical to the system used on the XK engine in the Series III XJ6 cars. The Lucas fuel injection system on the 3.6L AJ6 engines in these early XJS cars sensed engine load using a Manifold Air Pressure (MAP) sensor just like the V12 cars from the same era. Later 3.6L AJ6 engines as used in the 1986-1989 XJ40 cars had a crank sensor type of ignition system with a bare distributor that only carried the spinning ignition rotor inside the distributor cap. The fuel injection system used on the later 3.6L AJ6 engines used a hot wire Mass Air Flow sensor to determine engine load.

Vehicles using the 3.6 were:

1984-1989 Jaguar XJS
1986-1989 Jaguar XJ6
1986-1989 Jaguar XJ6 Sovereign
1986-1989 Daimler

[edit] 2.9

The 2.9 used a SOHC head from the Jaguar V12 engine, and was prone to failure. The block is the same as the 3.6, with the crankshaft and pistons lowering the stroke to 74.8 mm. Only the 1984-1989 Jaguar XJ6 used the 2.9. It was used for the entry-level XJ6 in Britain and Europe but rarely, if ever, seen in models exported to the US. The SOHC 2.9, which was generally considered somewhat underpowered for such a large car, was discontinued in 1992 and replaced with a DOHC 3.2 (essentially identical to the DOHC 4.0).

[edit] 4.0 (1989-1994)

The 24 valve DOHC 4.0 L (3980 cc) version replaced the 3.6 L AJ6 in 1989. It featured a longer 102 mm stroke, and generated 183 kW (235 hp) power and 392 Nm (290 Lb-Ft) of torque. The 4.0L engines as used in the 1990-1994 XJ40 cars continued with the crank sensor and empty distributor type of ignition system and the hot wire Mass Air Flow sensor type of fuel injection control system as the 1988-1989 3.6L XJ40 cars.

[edit] 3.2 (1990-1994)

A 24 valve DOHC 3.2 L, essentially a shorter-stroke (83 mm) 4.0 L, replaced the 12 valve SOHC 2.9 in 1990. It produced 149 kW of power and 298 Nm of torque, and proved a popular engine in Europe (sales outnumbered 4.0 L saloons roughly 4:1) but was not exported to the America.

Following the launch of the Aston Martin DB7, a car based on Jaguar's original replacement platform for the XJ-S (which was discarded in favour of the XK8 based on the X300 platform, note the traditional Jaguar 6-dial dashboard and ski-slope), the Jaguar AJ6 was used by Aston Martin as well. This version featured an Eaton supercharger.

Cars using the 4.0 and 3.2 included:

Jaguar XJS (4.0 only)
Aston Martin DB7 (modified, supercharged 3.2)
Jaguar XJ6
Jaguar XJ6 Sovereign
Jaguar XJ6 Sport
Daimler

[edit] AJ16

Both the 3.2 and 4.0 were substantially revised for the 1994 launch of the new X300 saloon. These are the "AJ16" engines, both now featuring coil-on-plug distributorless ignition, new engine management systems, magnesium alloy heads, etc. The AJ16 was discontinued with the launch of the AJ-V8 (XK8 and XJ8 in 1996/7). Even now in 2007, it is already getting hard to get internal engine parts like correct bearing shells and pistons for these AJ16 motors so rebuilds a few years down the line may be challenging.

[edit] 4.0 / 3.2 (1994-1997)

For the launch of the new X300 saloon for 1995, substantial revisions were made to the 4.0 L and 3.2 L AJ6 engines. The new design was called the AJ16 to reflect the major differences between it and the original AJ6.

Cars using the 4.0 and 3.2 included:

[edit] AJ16S

A supercharged version of the 4.0 L AJ16 was released in 1996 in the Jaguar XJR which used an Eaton blower to boost output to 240 kW and 512 Nm or 322 hp and 377 Lb-Ft.

[edit] See also

Jaguar Cars, a subsidiary of Ford since 1989, road and race car timeline, 1940s-1980s v • d • e
Type	1940s					1950s										1960s										1970s										1980s
	5	6	7	8	9	0	1	2	3	4	5	6	7	8	9	0	1	2	3	4	5	6	7	8	9	0	1	2	3	4	5	6	7	8	9	0	1	2	3	4	5	6	7	8	9
Sports				XK120							XK140			XK150			E-type S1							E S2			E-type S3				XJ-S						XJ-S HE
Saloon											Mark 1					Mark 2, 240, 340
																				S-Type											XJ-C
																						420		XJ6 Ser I						XJ6 Ser II						XJ6 Ser III								XJ6 (XJ40)
	Mk IV				Mk V			Mk VII				Mk VIII			Mk IX			Mk X				420G						XJ12		XJ12 S II						XJ12 Ser III
Supercar														XKSS
Racing							C-Type			D-Type								E-Type				XJ13										XJ-C		Jaguar XJ41& XJ42						XJRs
Corporate ownership	Independent																					BMH		British Leyland															Independent					Ford