JAGUAR S TYPE 1999 1.G Powertrain Manual

V6 Engine
6
Basic Engine
Engine Structure
Basic engine construction is similar to the V8 in
that a structural bedplate is used which bolts to
the cylinder block to provide a very strong
housing for the crankshaft, minimising vibration.
Both units are of cast aluminium alloy and are
accurately aligned together by the use of eight
hollow dowels.
The cylinder block is fitted with dry cast iron
liners.
The oil sump is an aluminium alloy casting which
combines a sump body and oil pan in a single
structural component. The sump mounts to the
bedplate via an aluminium gasket incorporating a
silicone rubber seal.
D.303.1360
D.303.1360
ENGINE STRUCTURE
D.303.1364
ENGINE DATA LOCATIONS
Engine Identification Data
An engine identification code tag is located on the
bank 2 side of the front cover assembly.
Mains bearing selection codes are located at the
rear of the cylinder block and on the rear face of
the crankshaft flange. The two codes are
compared using reference data provided in the
JTIS service information to identify the correct
bearing.
Engine identification codeMains bearing selection codes
D.303.1364
AJ-V6/AJ28

D.303.1210
V6 EngineAJ-V6/AJ28
7 CRANKSHAFT
D.303.1210
D.303.1208
CONNECTING ROD AND PISTON
D.303-1208
Crankshaft
The forged steel crankshaft runs in four
aluminium/tin main bearings with the lower
bearing shells supported in cast iron inserts in the
bedplate. Fore and aft location of the shaft is set
by the rear bearing assembly which consists of an
upper shell and thrust half washer and a lower,
flanged, thrust bearing shell. A keyway locates the
crankshaft timing sprockets, timing pulse ring and
crankshaft damper to the crankshaft.
Connecting Rods and Pistons
The connecting rods are manufactured from
sintered iron. The bearing caps are produced by
the fracture split method (as used on the V8
engines) to provide a strong, accurately mated
assembly. Bearing shells are of aluminium/tin
alloy.
The pistons are made of aluminium alloy with
valve cut-outs in the piston crown to allow for the
extra inlet timing advance of the VVT system.
Four cut outs are provided to enable a common
piston to be used in each engine bank. The piston
is fitted with two compression rings and an oil
control ring assembly.

V6 Engine
8
Cylinder Head
The aluminium alloy cylinder heads have square
squish combustion chambers with four valve
ports and a central spark plug. Each head is
aligned to the cylinder block via two split hollow
dowels and sealed with a composite stainless steel
gasket. Steel balls (10.11mm diameter) are used
to plug the external bores of the oilway drillings
and cup plugs are fitted to the water jacket
openings. Two half round aluminium cap inserts
are fitted via a sealant at the rear of the head.
Cam Cover
The cylinder heads are fitted with lightweight
polyester cam covers, (bank 2 is silver colored)
with silicone seals, to save weight and reduce
airborne noise. A central aperture allows access to
the coil on plug units and a second hole has a
grommet through which the VVT oil control valve
protrudes. The oil filler hole is in the LH cover.
D.303.1368
CYLINDER HEAD
D.303.1207
CAM COVER
D.303.1207
Cylinder Head Assembly
D.303.1368
AJ-V6/AJ28

V6 EngineAJ-V6/AJ28
9
Camshafts and Valve Gear
The basic camshaft consists of individual
machined cam lobes, thrust washer and end plug
assembled on a steel tube. The exhaust camshafts
also have a pressed on drive sprocket, forming a
single camshaft assembly. On the inlet camshaft
the drive sprocket is fixed to the VVT unit which
is removable but the rear end of the camshaft is
fitted with a pressed on multi-tooth sensor ring.
Each camshaft is supported in four bearings with
the front (thrust) bearing cap having a special
oilway for the VVT unit (see VVT section): on the
exhaust camshaft this oilway is redundant. The
bearing caps are made of aluminium.
The cams actuate the valves via direct acting
mechanical bucket tappets made of lightweight
aluminium with phosphate coated cast iron shims
D.303.1209
CAMSHAFTS AND VALVE GEAR
D.303.1209
mounted on top. The valve components are of
lightweight design with 5.5mm valve stems.
VVT Unit
Inlet Camshaft
Exhaust Camshaft

V6 Engine
10
D.303.1204
CAMSHAFT DRIVE
D.303.1204
AJ-V6/AJ28
Camshaft Drive
Two timing chains are used, one for each cylinder
bank and driven by separate sprockets keyed to
the crankshaft. The chains are of the silent-type,
with a multiple link construction and sprocket
engagement on one side only.
Each chain has a hydraulic tensioner, fed from the
engine oil supply, which acts on a pivoted
tensioner arm with side flanges. Fixed guides bear
on the drive side of the chains and are unique to
each side.
A single piece aluminium alloy front cover is
aligned to the cylinder block by two dowels andencloses the timing gear. The crankshaft front oil
seal fits into the front cover and the inner lip
bears on the crankshaft damper.
Crankshaft timing disc
VVT unit

V6 EngineAJ-V6/AJ28
11
D.303.1220
IGNITION COIL COVERIgnition Coil Cover
A plastic ignition coil cover, embossed with
ÔJAGUAR V6Õ, is fitted to engine bank 2 only. The
cover is attached via two push fit studs on the
camshaft cover.
D.303.1220

V6 Engine AJ-V6/AJ28
12
D.303.1216
Exhaust Manifold
The exhaust manifolds are of cast iron with a
threaded hole in the bank 1 manifold for the EGR
pipe or blanking plug (if EGR not fitted). Each
manifold is fitted with a heat shield constructed
of a fibre compound sandwiched between an
aluminium coated carbon steel shell.
Engine Mountings
The engine is supported at each side on
hydramounts fitted between the aluminium alloy
engine brackets and the No 2 front cross member.
The hydramounts are similar to those on the XJ
and XK Series and have an integral heat shield
and anti-separation restraint. EXHAUST MANIFOLD AND HEATSHIELD
D.303.1216
D.303.1367D.303.1367
ENGINE MOUNTING

V6 EngineAJ-V6/AJ28
13
Oil Distribution
(see illustration on page 14)
Oil distribution within the block and cylinder
heads is similar to that of the V8 engine, the main
differences being in the filter and cooler
arrangement and the method of supplying the
VVT system.
Oil is drawn from the sump through the strainer
by the crankshaft driven pump, passes through
the externally mounted filter and oil cooler and
returns to the block. Distribution is via the main
gallery and crankshaft oilways to the lower
crankcase components and via branch feeds to
the chain tensioners and then cylinder head
components. Extra oilways in the cylinder heads
provide a built-in feed for the VVT components
(see VVT section).
Oil Pump
The oil pump is of the inner/outer rotor type with
the directly driven inner rotor located via flats on
the crankshaft and the body of the pump bolted
to the cylinder block. The oil pressure relief valveis located in the lower LH side of the pump. An
oil pick-up tube and strainer is bolted to the
pump inlet and projects directly down to the
sump. Oil foaming is reduced by the windage tray
bolted to the underside of the bedplate.
D.303.1211
Lubrication System
OIL PUMP
D.303.1211

V6 Engine
14
J.303.1289
ENGINE OIL SUPPLY
J.303.1289
AJ-V6/AJ28
1. VVT oil feed
2. Bank 1 camshaft oil feeds
3. Bank 2 camshaft oil feeds
4. Oil cooler
5. Oil filter
6. Oil filter adaptor7. Oil pressure switch
8. EOT sensor
9. Oil pressure relief valve
10. Oil strainer
11. Oil pump
12. Timing chain tensioner oil feed
1
21
3
4
5
678
12
910
11
12

V6 EngineAJ-V6/AJ28
15
Oil Cooler and Filter Mounting
The oil filter and oil cooler are mounted slightly
away from the cylinder block on an aluminium
alloy adaptor which is an integral extension of the
LH engine mount. The oil filter is a replaceable
canister screw on type and the cooler is fixed by a
single through bolt to the adaptor. Both
components are connected to the cylinder block
through internal oilways in the adaptor casting
and via an interfacing filter mounting in the
block. A hollow bolt passes through the
adaptor/engine mount and screws into the centre
channel of the block filter mounting to provide
the oil return from the cooler to the cylinder
block.
The adaptor mounted oil cooler is an oil to water
heat exchanger and the coolant matrix is
connected via hoses into the main coolant system
at the radiator bottom hose (see Cooling System).
ENGINE OIL PRESSURE AND OIL TEMPERATURE SENSORS
D.303.1205
OIL COOLER AND FILTER ASSEMBLY
EOP Sensor
EOT Sensor
D.303.1205
D.303.1371
Engine Oil Pressure (EOP) and Oil
Temperature (EOT) Sensors
EOP and EOT sensors are fitted on the LH side of
the cylinder block in the return feed from the oil
cooler. The oil temperature is monitored to
provide data for the VVT system.
Oil Cooler
Hollow Bolt
Engine Mount/
Oil Cooler Adapter