Jaguar AJ6 engine
The
AJ6 (and 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.
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.
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 with 325 Nm of torque.
Vehicles using the 3.6 were:
* 1984-1989
Jaguar XJS* 1984-1989
Jaguar XJ6* 1984-1989
Jaguar XJ6 Sovereign* 1984-1989
Daimler2.9
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).
4.0 (1989-1994)
The 24 valve DOHC 4.0 L (3980 cc) version replaced the AJ6 in
1989. It featured a longer 102 mm stroke, and generated 183 kW (235 hp) power and 392 Nm torque.
3.2 (1993-1994)
A 24 valve DOHC 3.2 L, essentially a shorter-stroke (83 mm) 4.0 L, replaced the 12 valve SOHC 2.9 in
1993. 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*
DaimlerBoth 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).
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 4.0 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:
*
Jaguar XJS (4.0 only)
*
Jaguar XJ6*
Jaguar XJ6 Sovereign*
Jaguar XJ6 Sport*
DaimlerAJ16S
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.
*
Jaguar XK6 engine*
Jaguar V12 engine*
Jaguar AJ-V6 engine*
AJ6 Performance
