1998 JAGUAR X308 valve

Thi
s sensor uses a piezo-electric sensing element to detect kn
ock which may occur under acceleration at critical conditions.
Should detonation be present the ECM will retard ignition timing of individual cylinders.
Exhaust G
as Recirculation
The EGR
valve (where fitted) reduces NOx
emissions by recirculating a portion of the exhaust gases back into the inlet
manifold.
Heated Oxyg
en Sensors
The h
eated oxygen sensors, one per bank, are situated upstream of the catalysts. Integral
to the sensors are heaters
(under ECM control) which allow the sensor s to reach their operating temperature as soon as possible after engine start. A
comparison between the level of oxygen in the exhaust gas to that in the atmosphere produces an output signal. This signal
is used by the engine closed loop fuel strategy to make fuelling corrections and so control overall emission levels.
Oxygen Sensors

Thes
e sensors, one per bank, are situated downstream of the
catalyst. The comparison of upstream and downstream signals
allows determination of cata lyst conversion efficiency.




Knock Sensor

En
gine - Valve Clea
rance Adjustment
Gene
ral Procedures
S
p
ecial Tool(s)

Tappet adjustment
3
03-
540

Ai
r gun, fan nozzl
e
303-590
1. Open the engine compartment and fit paintwork protection
sheets. Open to the service position.
2. Carefully remove both engine covers, taking care not to
damage the plasti c fixings or the rubber inserts.

3. Disc
onnect the batt
ery ground cable.
Re
move the battery cover.
4. Remove the cam cover from the 'A' bank and the 'B' bank;
including the purge valve, the on-plug ignition coils and the air
intake tube / air flow meter / air cleaner cover assembly. Refer
to Operations 12.29.43 and 12.29.44.
5. Check, and note the valve cleara nces, as described earlier in
this section.
6. Use a rag to wipe up as much oil as possible from the tappet
wells.
7. Valve adjustment involves considerable repetition. A SUMMARY
OF THE PROCEDURE follows:
1. Fit the adjusting tool base plate to one cylinder head.
2. Rotate the crankshaft to position four valves ready for
adjustment.
3. Use the attachment part of the special tool to adjust two valve clearances. Transfer the attachment and
adjust the other two valve clearances.
4. Remove the attachment pa rt from the adjusting tool
base plate.

5.
Repeat steps 2 to 4 three
more times until all sixteen
valves on the first cylinder head have been adjusted.
6. Repeat steps 1 to 5 for the other cylinder head.
7. Remove all equipment and reassemble the engine.
8. The following instructions describe the PROCEDURE FOR
ADJUSTING THE VALVE CLEARANCES.

9. F
it the base plate of the tappet
adjusting tool 303 - 540 to one
of the heads; use the bolts which are supplied with the tool.
It
should be fitted along the head, between the two
camshafts, and bolted to the tapped holes which normally
secure the cam cover.
10. Rotate the crankshaft so that there are four valves which are
'off the cam'(cam lobes uppermos t), so that their clearance
may be measured.

11
.
CAUTION: Do not rotate the crankshaft while the
attachment is fitted to the base plate.
Fit the attachment of 303 - 540 to the base plate. 1. Set the fingers of the attachment to the highest position (unscrew the knurled bolts).
2. Fit the attachment to the base plate, adjacent to the first two valves to be adjusted.
3. Tighten the screws to secure the attachment to the base plate.

12
.
Position the fingers on to the outer edges of the tappet. It is
essential that the recessed step on each finger, locates on the
edge of the tappet as indicated. The use of a mirror will help,
as viewing access is restricted.

13
.
Tighten the knurled bolts to compress the valve springs, until
a firm resistan ce is felt.

14
. WARNING: TH
E FOLLOWING OPERATIONS REQUIRE
THE USE OF COMPRESSED AIR - ALWAYS WEAR SUITABLE EYE
PROTECTION.
Remove, clean and measure the shims.
1. Surround the immediate wo rking area with clean rag
to contain any loose objects and shims displaced by
the compressed air.
2. Use 303 - 590 Air Gun (with a fan nozzle) aimed at the edge of the shim to lift it from the tappet.
Remove the shim from each tappet, noting the
position of each.
15 . Cl
ean and measure the thickness of each shim.
16. Assess the increase or decrease required in shim thickness to
produce the correct valve clearance.
17. Select two shims of the correct size, lubricate each and fit
each to the respective tappet (as calculated in the previous
step). Shims must be fitted with the size marking facing the
tappet NOT the cam.

18 . Loos
en the knurled screws on 303 - 540 attachment to allow
the valve springs to return to their normal position.
19. Check the valve clearance of the two valves. If the clearance
is correct, remove the attachment from the base plate. transfer
the attachment to the other two valves which are in position to
be adjusted.
20. Repeat the adjustment procedure, as described in the
Summary.
21. Refit the cam covers and associated components. Refer to
Operations 12.29.43 and 12.29.44.
22. Refit the engine covers.
23. Check the engine oil level; rectify as necessary.
24. Move the engine compartment cover from the service position
and connect the gas struts.
25. Remove the paint protection sheets and close the cover.
26. Connect the battery and fit the battery cover.
Refe
r to the Battery Reconnection Procedure 86.15.15.

E
ngine - Valve Clearance Check
Gen
eral Procedures

1.
Open the engine compartment and fit paintwork protection
sheets. Open to the service position.
2. Carefully remove both engine covers, taking care not to
damage the plasti c fixings or the rubber inserts.

3. Di
sconnect the batt
ery ground cable.
R
emove the battery cover.
4. Remove the cam cover from the 'A' bank and the 'B' bank;
including the purge valve, the on-plug ignition coils and the air
intake tube / air flow meter / air cleaner cover assembly. Refer
to Operations 12.29.43 and 12.29.44.
5. Rotate the crankshaft so that there are four valves which are
'off the cam' (cam lobes upperm ost), so that their clearance
may be measured.
6. Measure the gap on each of the four valves. Note which valve
has been measured, along with its relevant clearance.
7. Rotate the crankshaft a small am ount so that the next four
valves are 'off the cam'. Measure and note the clearances.
Re
peat this step
a further six times, until all valve
clearances have been measured and noted.
8. Refit the cam covers and associated components. Refer to
Operations 12.29.43 and 12.29.44.
9. Refit the engine covers.
10. Move the engine compartment cover from the service position
and connect the gas struts.
11. Remove the paint protection sheets and close the cover.
12. Connect the battery and fit the battery cover.
Re
fer to the Battery Reconnection Procedure 86.15.15

2. In
stall the camshaft caps to their respective locations (inlet 0 to 4
and exhaust 5 to 9 from the front) and in the correct orientation
(arrow to front of engine).
3. Install and tighten the cap securing bolts. Tighten evenly, in stages, to 10 Nm.
19. Install the camshaft locking tool 303 - 530, align the camshafts as
necessary.

20 . Install the chain guide
.
The
c
hain guide must be installed so that the slotted hole is towards
the top, and the rais ed shoulder to the cylinder block.
1. Install the chain guide to the block and locate it onto the upper retaining pin.
2. Install the retaining bolt and tighten it to 12 Nm.

21. P
ush the secondary chain tensioner piston into the body to provide
clearance for installing the chain.
1. Insert a thin rigid wire through the hole in the end of the tensioner
piston to displace the ball from the non-return valve seat.
2. With the wire in position, press the piston fully into the tensioner body.
Rem
ove the wire.

22 . Ins
tall the secondary chain tensioner to the engine.
1. Fully seat the tensioner to the cylinder head.
2. Install the two bolts which secure the tensioner and tighten to 12 Nm.

23 . N
OTE: Assemble the VVT unit, the exhaust camshaft sprocket and the
secondary chain, in preparation for installing to the engine.
Install the VVT unit to the engine.
1. Install the above assembly to the camshafts with the chain correctly positioned over the tensioner; VVT unit to the inlet and
the sprocket to the exhaust.
2. Install, but do not tighten, each bolt which secures the VVT unit and the exhaust sprocket to the camshafts.
24. Install the chain tensioning tool 303 - 532 to the exhaust camshaft
sprocket.

Re
position the sprocket (and the VVT unit) for the most advantageous
position for use of the tool.
R
emove the tool.

25
.
Install the primary timing chain.
R
eposition the VVT unit forwards on the cam journal (do not rotate it)
to allow the chain to cl ear the head casting. Disconnect the primary
chain from the Ty-strap.
1. Install the primary chain to position over the crankshaft sprocket and the VVT unit sprocket. There mu st be no slack on the drive
side of the primary chain and the VVT unit must not be rotated on
the camshaft.

26
.
Install the primary chain tensioner blade.
1. Position the tensioner blade to the cylinder block.
2. Install the retaining / pivot bolt and tighten it to 14 Nm.

27
.
Push the primary chain tensioner piston into the body to provide clearance
for installing.
1. Insert a thin rigid wire through the hole in the end of the tensioner
piston to displace the ball from the non-return valve seat.
2. With the wire in position, press the piston fully into the tensioner body.
Re
move the wire.

28
.
Assemble the tensioner.
1. Install the two mounting bolts to the tensioner.
2. Locate the tensioner back-plate to the two bolts.
29. Install the tensioner to the cylinder block.
1. Position and align the tensioner to the cylinder block and to the mating slot on the rear face of the tensioner blade.
2. Install and tighten the two bolts to 12 Nm.

To th
e upper face of each bearing surface (two places) in the cylinder
head.
To th
e upper face of each bearing surface (two places) in each bearing
cap.
On
the cam lobes ONLY, not on the base circle area.

17
.
Install the camshafts.
1. Install the camshafts to position in the cylinder head, with the timing flats uppermost.
2. Install the camshaft caps to their respective locations (inlet 0 to 4 and exhaust 5 to 9 from the front) and in the correct orientation
(arrow to front of engine).
3. Install and tighten the cap securing bolts. Tighten evenly, in stages, to 10 Nm.
18. Install the camshaft locking tool 303 - 530, align the camshafts as
necessary.

19
.
Install the chain guide.
• NOTE: The chain guide must be installed so that the slotted hole is
towards the top, and the raised shoulder to the cylinder block. 1. Install the chain guide to the block and locate it onto the upper retaining pin.
2. Install the retaining bolt and tighten it to 12 Nm.

20
.
Push the secondary chain tensioner piston into the body to provide
clearance for installing the chain.
1. Insert a thin rigid wire through the hole in the end of the tensioner
piston to displace the ball from the non-return valve seat.
2. With the wire in position, press the piston fully into the tensioner body.
Re
move the wire.

21
.
Install the secondary chain tensioner to the engine.
1. Fully seat the tensioner to the cylinder head.
2. Install the two bolts which secure the tensioner and tighten to 12 Nm.
22. Install the VVT unit to the engine.
A
ssemble the VVT unit, the exhaust camshaft sprocket and the