The AJ-V8 4.0 litre, engine is the first of a new family of Jaguar engines. Designed to give excellent
performance, refinement, economy and low vibration levels it also conforms to the strictest emission
legislation. Weighing only 200 kilograms (441 lb), the engine is shorter by 12 inches (300 mm) than the
current AJ16 4.0 litre engine. Compression ratio is 10.75:1, with four valves per cylinder. The cylinder
heads, block and bedplate are all cast aluminum. Cylinders have electro-plated bores which reduce
piston friction, improve warm-up and oil retention. A variable valve timing system has been introduced
to give improved low and high-speed engine performance and excellent idle quality. The valve gear is
chain driven for durability. Low valve overlap improves engine idle speed and low residual fuel levels
which improves combustion and reduces hydrocarbon emissions. The inlet manifold is a one-piece,
composite moulding with integral fuel rails connecting to the eight side feed fuel injectors. Air flow into
the engine is via an electronic throttle assembly. Movement of the throttle is controlled by sensors in
the throttle assembly through the ECM. The engine has a low volume, high velocity, cooling system
which achieves a very fast warm-up with reduced and even metal temperatures in the combustion
chamber and increased bore temperatures.
The generator, A/C pump, and PAS pump are mounted to the cylinder block on rigid cradle supports.
Accessory drive is from a single, 7-ribbed vee belt. Hydraulic engine mounts minimise noise and
A new engine management system adjusts fuel and ignition settings, monitors and controls exhaust
emissions and provides an on-board diagnostic capability.
The transmission is a new ZF 5-speed, automatic, electronically controlled unit.
The unit is oil filled for life so does not have an oil gauge (dipstick). Two driver selected modes are
available, sport or normal. The TCM is programmed with cruise, traction, gradient, warm-up and hot
mode features. It also provides an on-board diagnostic capability.
The engine and transmission meet OBDII USA environmental regulations.
Default limp home modes for both engine and transmission are provided.