1997 JAGUAR XJ6 Crankshaft

23Clean and lubricate the lower tensioner.
Fill the lower tensioner oil reservoir with engine
oil and refit it on the engine block, aligning the
notch in the tensioner with the lug on the back
of the guide (see illustrations). This should
remove all slack from the lower timing chain. If
not, push the lower tensioner guide back and
forth a few times to prime the tensioner.
24Refit the upper chain tensioner guide and
mounting bracket to the engine block.
Caution: Before fully tightening the
mounting bracket to the engine block,
make sure the mount and chain guide are
clear of the lower chain, auxiliary sprocket
and intermediate sprocket. If necessary,
position the mount for clearance before
tightening the mounting bolts.
25Refit the oil pump drive chain and
sprocket to the crankshaft (see Section 13).
26Refit the upper chain fixed guide to the
engine block and place the upper timing chain
over the intermediate sprocket and auxiliary
shaft sprocket, draping the excess chain over
the top of the fixed guide. Lubricate the chain
and sprockets with clean engine oil.27Gather the loose portion of the upper
timing chain and place it between the upper
guides. Use a large rubber band to hold the
two guides snugly around the chain (see
Section 11).
28If necessary, renew the intermediate shaft
seal (see illustrations).
29Apply a thin coat of RTV sealant to the
engine side of the front cover and RTV sealant
to the oil-pan mating surface (bottom of the
front cover), then refit the front cover. Note:
Make sure the top surface of the cover aligns
with the top surface of the engine block, by
checking with a straightedge(see illustration).
30Refer to Section 11 for refitting of the
cylinder head and Section 10 for refitting of
the camshafts and connection of the upper
timing chain to the two camshaft sprockets.
31The remainder of the refitting is the
reverse of the removal procedure. If your car
is equipped with the hydraulic/self-levelling
suspension, refit the drive coupling and
coupling disc to the intermediate shaft (see
illustrations 8.9a and 8.9b). Coat the
mounting surface of the pump with RTVsealant and make sure the tang on the pump
aligns with the slot in the intermediate shaft
before bolting the pump to the front cover.
Refer to Section 7 for refitting of the
crankshaft spacer, damper and puller.
Caution: DO NOT start the engine until
you’re absolutely certain that the timing
chains are installed correctly. Serious and
costly engine damage could occur if the
chains are installed wrong.
32Run the engine and check for proper
operation.
9 Auxiliary shaft- renewal
3
Caution: If the stereo in your vehicle is
equipped with an anti-theft system, make
sure you have the correct activation code
before disconnecting the battery.
1Refer to Chapter 10 and remove the power
steering pump, without disconnecting the
hoses. Remove the plastic power steering
pump drive coupling disc.
2A•8 Engine in-car repair procedures
8.28a Drill a small hole in the intermediate
shaft seal, thread a sheet metal screw into
it and use a small slide-hammer pull the
seal out of the cover8.28b Drive the new seal in with a seal-
driver or socket, to the same depth as the
original seal8.29 Bolt the front cover on hand tight, use
a straightedge to make sure the cover’s
top surface is level with the top of the
engine block, then tighten the cover bolts
3261 Jaguar XJ6 8.23a Add oil to the reservoir in the lower tensioner . . .
8.23b . . . and refit the tensioner against the guide -
after it’s installed, push the tensioner guide back and forth
a few times to prime the tensioner

2Refer to Section 8 and remove the front
cover and upper and lower timing chains.
3Remove the power steering drive coupling
from the auxiliary shaft (see illustration).
4Use a small drill to drill holes in the oil seal,
then use a slide-hammer puller to remove the
seal from the rear of the auxiliary shaft
housing (see illustration).
Caution: Drill straight and carefully to avoid
damaging the auxiliary shaft.
5Use a pair of snap-ring pliers to remove the
snap ring from the rear of the auxiliary shaft
(see illustration).
6Pull the auxiliary shaft out toward the front
of the engine.
7Remove the three internal hex-head bolts
and the auxiliary shaft housing.
8Examine the surface of the auxiliary shaft,
it’s sprocket, and the distributor drive-gear. If
there is noticeable wear or damage, replace
the auxiliary shaft assembly with a new one
(see illustration).
9If the auxiliary shaft housing has been
removed, clean it, scrape away the old gasket
material from the housing and the engine
block and refit the housing with a new gasket
(see illustration).
10Clean the auxiliary shaft, lubricate it with
engine oil and refit it through the front of the
block, then refit the washer (see illustration).
Refit the snap-ring(refer to illustration 9.4).11The new oil seal for the rear of the auxiliary
shaft comes with a plastic refitting sleeve that
keeps the seal lip from folding back during
refitting. Keep this sleeve in place until the seal
is fully installed. Tap the new seal into the
housing with a hammer and appropriate-size
socket until the seal is flush, then remove the
plastic sleeve (see illustration).
12The remainder of the refitting is the
reverse of removal. Note:When refitting the
distributor (see Chapter 5), use a new O-ring
to prevent oil leaks at the distributor.
13Run the engine and check for oil leaks at
the power steering pump-to-housing interface.10 Camshafts and valve lifters-
removal, inspection and
refitting
4
Removal
Note:The renewal of the camshafts requires
the use of several special tools. Read through
the procedure and acquire the special tools,
or their equivalent, before beginning work.
1Remove the valve cover (see Section 4).
2Refer to Section 3 and position the engine
at TDC for number 1 cylinder.
3Refer to Chapter 5 and remove the
distributor cap and set it aside along with the
spark plug leads. Mark the positions of the
distributor body and rotor.
4Using a feeler gauge, measure and record
the clearance between the intake and exhaust
camshaft lobes and the lifters for cylinder
number 1 (see illustration). Rotate the
crankshaft until the next cylinder in the firing
order is at TDC and check and record the
valve clearance for that cylinder. Following the
firing order, check and record the valve
clearance for the remaining valves with the
appropriate cylinder at TDC.
5Return the engine to TDC for cylinder
number 1. Using the special tool (Jaguar tool
no. 18G 1433), check the position of each
Engine in-car repair procedures 2A•9
2A
9.3 Use a screwdriver to hold the drive
coupling (arrowed) stationary while
removing the bolt9.4 Remove the auxiliary shaft seal with a
small slide-hammer puller9.5 Use snap-ring pliers to remove the
snap ring (arrowed) from the shaft - note
the three internal hex-head bolts retaining
the housing to the engine block
9.8 Inspect these areas of the auxiliary
shaft for wear
A Oil seal surface
B Bearing journalC Sprocket
D Distributor drive9.9 Refit the auxiliary shaft rear housing
with a new gasket, aligning the oil slot
(arrowed) with the housing
3261 Jaguar XJ6
9.10 Refit the washer before replacing the
snap-ring
9.11 Tap the seal squarely into the bore
with a socket until the seal is flush
with the housing, then remove the
plastic fitting sleeve

camshaft to ensure that they are truly at TDC
(see illustration). It may be necessary to
rotate the crankshaft slightly, to allow the tool
to fit into the slot. Once the camshafts are
positioned, DO NOT rotate the crankshaft
further.
6Check the TDC marks made on the
distributor body and refer to Chapter 5 for
removal of the distributor. Note:Plug the
distributor hole with a rag to keep out dirt.7Locate the upper timing chain tensioner on
the right front of the cylinder head. Loosen the
bolt on the clamp and swing the clamp away
from the tensioner return valve, then remove
the valve (see illustration).
8Remove the tensioner bolts and pull out the
tensioner.
9The camshaft bearing caps are each
retained by three bolts (the two front caps on
each camshaft have only two bolts), of whichone is a cylinder head bolt that threads into the
engine block. If the camshafts are being
removed as a step in cylinder head removal,
the following steps involving spacer blocks are
not required, just remove the bolts and caps,
then remove the camshafts. If the procedure is
being used for camshaft removal or adjustment
of the lifter shims, the procedure must be
followed exactly to maintain the cylinder head
gasket seal.
10To maintain a good seal on the cylinder
head gasket, if the cylinder head is not being
removed, a spacer block (Jaguar tool no.
18G 1435) is used to replace each camshaft
bearing cap as it is removed. Begin by
unbolting and removing intake cap no. 2.
Remove the large cylinder head bolt first, then
the cap bolts. Without delay, refit a spacer
block, with the cylinder head bolt, and tighten it
to 53 Nm (39 lbf ft) (see illustrations).
11Repeat paragraph 10 with the remainder
of the intake camshaft caps in sequence. After
cap 5 in the sequence, loosen the front and
rear caps alternately until valve spring
pressure is relieved from the camshaft (see
illustrations). Note:No spacer blocks are
required with the number 1 camshaft caps.
2A•10 Engine in-car repair procedures
10.7 Loosen this bolt (arrowed) and swing
the clamp away from the tensioner, then
use pliers to pull the valve out10.10a As each cap is removed . . .10.10b . . . replace it with the special
spacer block (arrowed) and tighten the
cylinder head bolt to 53 Nm (39 lbf ft)
3261 Jaguar XJ6 10.4 Measure the valve clearance with a feeler gauge inserted
between the heel of the camshaft lobe and the lifter
10.5 Position the camshaft alignment tool over each camshaft - the
projection on the tool only fits into the slot on the camshafts when
they are at TDC - flip the tool over to check the other camshaft
10.11a Each of the camshaft bearing caps
are stamped with I (intake) or E (exhaust)
and a number (arrowed)10.11b After cap no. 2 is replaced with a
spacer, repeat the procedure for the other
caps in the sequence shown - after cap 5,
loosen caps 6 and 7 alternately until valve
spring pressure is relieved

Inspection
8Clean and dry the pump body and both
rotors. Measure the outside diameter of the
outer rotor and thickness of both rotors.
9Place the outer rotor into the pump body
and use feeler gauges to measure the
clearance between the outer rotor and the
body (see illustration).
10Place a straightedge across the pump
body and measure between the straightedge
and the rotors to check the over-the-rotor
clearance (see illustration). Compare your
measurements to this Chapter’s Specifications
and renew the oil pump if any are beyond the
maximum allowable.
11Remove the oil pressure relief valve cap.
Remove and clean the relief valve components
(see illustration).
12Clean all components with solvent and
inspect them for wear and damage. If
excessive wear, damage or if any clearance is
beyond the Specifications, renew the entire
pump as an assembly.
13Check the oil pressure relief valve piston
sliding surface and valve spring. If either the
spring or the valve is damaged, they must be
renewed as a set.
Refitting
14Lubricate the drive and driven rotors with
clean engine oil and place them in the casewith the marks facing out. Apply a thin coat
of anaerobic sealant (Loctite 510 or 518) to
the gasket flange and refit the cover (see
illustration).
15Lubricate the oil pressure relief valve
piston with clean engine oil and refit the valve
components into the oil pump body (see
illustration 13.11).
16Apply a thin coat of anaerobic sealant
(Loctite 510 or 518) to the oil pump-to-engine
block-mounting surface, position the oil pump
body against the engine block and refit the
mounting bolts, tightening the bolts to the
torque listed in this Chapter’s Specifications.
Follow a criss-cross pattern when tightening
the bolts to avoid warping the oil pump body.
17If using the original oil pump, refit the
original sprocket shim pack (see illustration).
If a new pump is installed, start off with a
0.38 mm (0.015-inch) thick shim pack, refit the
drive sprocket and align the sprocket as
follows.
18Use a straightedge to check the alignment
of the oil pump sprocket with the crankshaft
sprocket (see illustration). If they are not
aligned, increase or decrease the shim pack at
the oil pump sprocket until alignment is correct,
then secure the oil pump sprocket bolts by
bending up the sheetmetal tabs. Note:You
may be able to use all or part of the original
shim pack from the original oil pump (if a new
pump is being fitted). If required, shims areavailable in 0.127 mm (0.005 inch), 0.254 mm
(0.010 inch) and 0.508 mm (0.020 inch) sizes.
19Fit new O-rings to each end of the transfer
tubes and refit the tubes into the transfer
housing. Note:Use petroleum jelly to lubricate
the O-rings.
20Apply a thin coat of RTV sealant to the
engine block-mounting surface of the transfer
housing. Lift the transfer housing and tubes
into place and push the front of the tubes
in the back of the oil pump, until you can start
the transfer housing-to-engine block bolts.
Tighten the bolts to the torque listed in this
Chapter’s Specifications.
21Refit the remaining parts in the reverse
order of removal.
22Add oil, start the engine and check for oil
pressure and leaks.
23Recheck the engine oil level.
14 Driveplate-
removal and refitting
4
Removal
1Raise the car and support it securely on
axle stands, then refer to Chapter 7 and
remove the transmission. If it’s leaking, now
would be a very good time to renew the front
pump seal/O-ring.
2A•16 Engine in-car repair procedures
13.9 Measure the outer rotor-to-body
clearance with feeler gauges (arrowed)13.10 With a straightedge held tight to the
pump surface, measure the clearance over
the rotors with feeler gauges13.11 Oil pressure relief valve components
A Relief valve cap
B TubeC Spring
D Valve
13.14 Apply a thin coat anaerobic sealant
(Loctite 510 or 518) to the pump cover
sealing surface
13.17 Refit the original shim pack
(arrowed) if the original pump is being
used - if a new pump is being installed,
refit a 0.38 mm (0.015-inch) shim pack
3261 Jaguar XJ6
13.18 Check the oil pump and crankshaft
sprocket alignment with a straightedge -
add or subtract shims until the sprockets
are aligned for smooth chain operation

2Use a centre punch or paint to make
alignment marks on the driveplate and
crankshaft to ensure correct alignment during
refitting(see illustration).
3Remove the bolts that secure the driveplate
to the crankshaft. If the crankshaft turns,
wedge a screwdriver through a hole in the
driveplate to keep it from turning (see
illustration).
4Remove the driveplate from the crankshaft.
A spacer is located behind the driveplate(see
illustration). Pry it off and store it with the
driveplate.
Warning: The ring-gear teeth
may be sharp, wear gloves to
protect your hands when
handling the driveplate.
Refitting
5Clean the driveplate to remove grease and
oil. Inspect the surface for cracks. Check for
cracked and broken ring gear teeth. Note:If
there is any damage to the driveplate, replace
the driveplate with a new driveplate, a new
spacer and new bolts. Improved parts are
available as a set from the dealer.
6Clean and inspect the mating surfaces of
the driveplate and the crankshaft. If the
crankshaft rear seal is leaking, renew it before
refitting the driveplate (see Section 15).
7Position the driveplate against the
crankshaft. Be sure to align the marks made
during removal. Some models may have an
alignment dowel or staggered bolt holes to
ensure correct refitting. Before refitting the
bolts, apply thread-locking compound to the
bolt threads.
8Wedge a screwdriver in the ring gear teeth
to keep the driveplate from turning and tighten
the bolts to the torque listed in this Chapter’s
Specifications. Follow a criss-cross pattern
and work up to the final torque in three or four
steps.
9The remainder of refitting is the reverse of
the removal procedure.
15 Crankshaft rear oil seal-
renewal
4
1The transmission adapter plate and
driveplate must be removed from the car for
this procedure (see Chapter 7).
2Remove the bolts, and detach the oil seal
retainer. Remove the gasket material from the
block and the seal retainer (see illustration).
3Position the oil seal and retainer assembly
between two wood blocks on a workbench
and drive the old seal out from the backside
(see illustration).
4The new seal must be driven into the
retainer plate from the engine side. Drive thenew seal into the retainer with a wood block
or a section of pipe slightly smaller in diameter
than the outside diameter of the seal (see
illustration). The seal should be driven in only
until it is flush with the transmission side of
the retainer.
Caution: The new seal comes with a
special plastic refitting sleeve inserted in
the seal. It is designed to allow the seal to
slide over the end of the crankshaft
without displacing the seal lip. Do NOT
remove this plastic sleeve until the retainer
and seal have been installed on the engine.
5Lubricate the seal area of the crankshaft
with engine oil. Apply a bead of RTV sealant
to the sealing surface of the retainer (see
illustration).
Engine in-car repair procedures 2A•17
2A
14.2 Mark the driveplate and the
crankshaft so they can be reassembled in
the same relative position14.3 Use a screwdriver to secure the
flywheel while the bolts are removed14.4 Pry off the driveplate spacer - if a
driveplate is replaced, the spacer should
be replaced also
15.2 Remove the bolts (arrowed) and the
crankshaft rear oil seal retainer from the
back of the engine block15.3 After removing the retainer assembly
from the engine block, support it between
two wood blocks and drive out the old seal
with a drift punch and hammer
15.4 Drive the new seal into the retainer
with a wood block
3261 Jaguar XJ6
15.5 Apply RTV sealant
to the sealing surface

6Slowly and carefully press the seal and
retainer squarely onto the crankshaft (see
illustration). The plastic sleeve may be
pushed out as the retainer seats on the engine
block. Remove the plastic sleeve.
7Refit and tighten the retainer bolts to the
torque listed in this Chapter’s Specifications.
8The remaining steps are the reverse of
removal.
16 Engine mounts-
check and renewal
3
1Engine mounts seldom require attention,
but broken or deteriorated mounts should be
renewed immediately or the added strain
placed on the driveline components may
cause damage or wear.
Check
2During the check, the engine must be
raised to remove the weight from the mounts.3Raise the car and support it securely on
axle stands, then position a jack under the
engine sump. Place a large wood block
between the jack head and the sump, then
carefully raise the engine just enough to take
the weight off the mounts. Do not position the
wood block under the drain plug.
Warning: DO NOT place any part
of your body under the engine
when it’s supported by a jack!
4Check the front mounts to see if the rubber
is cracked, hardened or separated from the
metal plates. Sometimes the rubber will split
down the centre.
5Check for relative movement between the
mount plates and the engine or frame (use a
large screwdriver or pry bar to attempt to
move the mounts). If movement is noted,
lower the engine and tighten the mount
fasteners.
6Rubber preservative should be applied to
the mounts to slow deterioration.
Renewal
7Disconnect the battery negative cable.
Caution: If the stereo in your vehicle is
equipped with an anti-theft system, make
sure you have the correct activation code
before disconnecting the battery.
8Raise the car and support it securely on
axle stands. Support the engine as described
in paragraph 3.
Caution: Ensure the cooling fan doesn’t hit
the shroud as the engine is raised.
9To remove either engine mount, remove the
nut from the engine bracket, then raise the
engine (see illustration).
10From underneath the car, lower the
steering gear (see Chapter 10) for access to
the nut retaining the insulator to the chassis
bracket.
11Refitting is the reverse of removal. Use
thread-locking compound on the mount
bolts/nuts and be sure to tighten them
securely.
12See Chapter 7 for transmission mount
renewal.
2A•18 Engine in-car repair procedures
3261 Jaguar XJ6 15.6 Refit the retainer and oil seal onto the crankshaft
16.9 Front engine mount (A)
and retaining nut to engine bracket (B)

3261 Jaguar XJ6
2B
Chapter 2 Part B
Engine removal and overhaul procedures
General
Cylinder compression pressure @ 300 rpm, warm
Standard . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10.6 to 11.3 bar (150 to 160 psi)
High compression models . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11.3 to 12.1 bar (160 to 170 psi)
Maximum variation between cylinders . . . . . . . . . . . . . . . . . . . . . . . . 0.8 bar (10 psi)
Oil pressure (engine warm)
At idle . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2.1 bar (30 psi) minimum
At 4000 rpm . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4.9 bar (70 psi) minimum
Cylinder head
Resurfacing limit . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 0.25 mm (0.010 inch) maximum
Minimum thickness (see text)
3.6 litre . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 129.6 mm (5.101 inches)
3.2 and 4.0 litre . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 129.7 mm (5.108 inches)
Valves and related components
Valve stem-to-guide clearance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 0.038 to 0.076 mm (0.0015 to 0.0030 inch)
Valve springs, free length . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 40.13 mm (1.580 inches)
Valve lifter
Diameter . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33.34 to 33.35 mm (1.3126 to 1.3130 inches)
Lifter-to-bore clearance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 0.02 to 0.05 mm (0.0008 to 0.0020 inch)
Crankshaft and connecting rods
Connecting rod journal
Diameter . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 52.97 to 52.99 mm (2.0856 to 2.0861 inches)
Taper and out-of-round limits . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 0.008 mm (0.0003 inch) maximum
Bearing oil clearance
3.6 litre . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 0.040 to 0.083 mm (0.0016 to 0.0033 inch)
3.2 and 4.0 litre . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 0.025 to 0.0068 mm (0.0010 to 0.0027 inch)
Connecting rod side clearance (endplay) . . . . . . . . . . . . . . . . . . . . . . . . 0.127 to 0.228 mm (0.005 to 0.009 inch)
Main bearing journal
Diameter . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 76.217 to 76.233 mm (3.0007 to 3.0012 inches)
Taper and out-of-round limits . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 0.008 mm (0.0003 inch) maximum
Bearing oil clearance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 0.040 to 0.083 mm (0.0016 to 0.0033 inch)
Crankshaft endplay (standard) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 0.101 to 0.254 mm (0.004 to 0.010 inch) CHECK ENGINE light . . . . . . . . . . . . . . . . . . . . . . . . . . . See Chapter 6
Crankshaft - inspection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19
Crankshaft - refitting and main bearing oil clearance check . . . . . . . 23
Crankshaft - removal . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14
Cylinder head - cleaning and inspection . . . . . . . . . . . . . . . . . . . . . . 10
Cylinder head - dismantling . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
Cylinder head - reassembly . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12
Cylinder compression check . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
Cylinder honing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17
Engine block - cleaning . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15
Engine block - inspection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16
Engine overhaul - dismantling sequence . . . . . . . . . . . . . . . . . . . . . . 8
Engine overhaul - general information . . . . . . . . . . . . . . . . . . . . . . . . 2
Engine overhaul - reassembly sequence . . . . . . . . . . . . . . . . . . . . . . 21Engine rebuilding alternatives . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
Engine - removal and refitting . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
Engine removal - methods and precautions . . . . . . . . . . . . . . . . . . . 5
General information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
Initial start-up and running-in after overhaul . . . . . . . . . . . . . . . . . . . 26
Main and connecting big-end bearings - inspection and selection . 20
Pistons/connecting rods - inspection . . . . . . . . . . . . . . . . . . . . . . . . 18
Pistons/connecting rods - refitting and big-end bearing
oil clearance check . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25
Pistons/connecting rods - removal . . . . . . . . . . . . . . . . . . . . . . . . . . 13
Piston rings - refitting . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22
Rear main oil seal refitting . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24
Vacuum gauge diagnostic checks . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
Valves - servicing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11
2B•1
Specifications Contents
Easy,suitable for
novice with little
experienceFairly easy,suitable
for beginner with
some experienceFairly difficult,
suitable for competent
DIY mechanic
Difficult,suitable for
experienced DIY
mechanicVery difficult,
suitable for expert DIY
or professional
Degrees of difficulty
54321

Engine block
Deck warpage limit . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 0.076 mm (0.003 inch)
Cylinder bore diameter
Standard
Size group A . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 90.990 to 91.003 mm (3.5823 to 3.5828 inches)
Size group B . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 91.005 to 91.018 mm (3.5829 to 3.5834 inches)
Oversize
0.25 mm (0.010 inch) OS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 91.259 to 91.272 mm (3.5929 to 3.5934 inches)
0.50 mm (0.020 inch) OS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 91.513 to 91.526 mm (3.6029 to 3.6034 inches)
Pistons and rings
Piston-to-bore clearance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 0.017 to 0.043 mm (0.0007 to 0.0017 inch)
Piston ring end gap
No.1 (top) compression ring . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 0.40 to 0.66 mm (0.016 to 0.026 inch)
No.2 (middle) compression ring . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 0.40 to 0.66 mm (0.016 to 0.026 inch)
Oil ring . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 0.30 to 0.55 mm (0.012 to 0.022 inch)
Piston ring groove clearance
No. 1 (top) compression ring . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 0.040 to 0.076 mm (0.0016 to 0.0030 inch)
No. 2 (middle) compression ring . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 0.040 to 0.076 mm (0.0016 to 0.0030 inch)
Torque wrench settingsNm lbf ft
Main bearing cap bolts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 136 to 142 100 to 105
Connecting rod cap nuts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 50 to 60 37 to 44
* Note:Refer to Part A for additional torque specifications.
2B•2 Engine removal and overhaul procedures
3261 Jaguar XJ6
1 General information
Included in this portion of Chapter 2 are the
general overhaul procedures for the cylinder
head and internal engine components.
The information ranges from advice
concerning preparation for an overhaul and
the purchase of replacement parts to detailed,
step-by-step procedures covering removal
and refitting of internal engine components
and the inspection of parts.
The following Sections have been written
based on the assumption that the engine has
been removed from the vehicle. For
information concerning in-vehicle engine
repair, as well as removal and refitting of the
external components necessary for the
overhaul, see Part A of this Chapter.
The Specifications included in this Part are
only those necessary for the inspection and
overhaul procedures which follow. Refer to
Part A for additional Specifications.
2 Engine overhaul-
general information
It’s not always easy to determine when, or if,
an engine should be completely overhauled,
as a number of factors must be considered.
High mileage is not necessarily an indication
that an overhaul is needed, while low mileage
doesn’t preclude the need for an overhaul.
Frequency of servicing is probably the most
important consideration. An engine that’s had
regular and frequent oil and filter changes, as
well as other required maintenance, will most
likely give many thousands of miles of reliableservice. Conversely, a neglected engine may
require an overhaul very early in its life.
Excessive oil consumption is an indication
that piston rings, valve seals and/or valve
guides are in need of attention. Make sure that
oil leaks aren’t responsible before deciding
that the rings and/or guides are bad. Perform a
cylinder compression check to determine the
extent of the work required (see Section 4).
Also check the vacuum readings under various
conditions (see Section 3).
Check the oil pressure with a gauge
installed in place of the oil pressure sender
unit (see illustrations)and compare it to this
Chapter’s Specifications. If it’s extremely low,
the bearings and/or oil pump are probably
worn out.
Loss of power, rough running, knocking or
metallic engine noises, excessive valve train
noise and high fuel consumption rates may
also point to the need for an overhaul,
especially if they’re all present at the same
time. If a complete tune-up doesn’t remedy
the situation, major mechanical work is the
only solution.An engine overhaul involves restoring the
internal parts to the specifications of a new
engine. During an overhaul, the piston rings
are replaced and the cylinder walls are
reconditioned (rebored and/or honed). If a
rebore is done by an automotive machine
workshop, new oversize pistons will also be
installed. The main bearings, big-end bearings
and camshaft bearings are generally replaced
with new ones and, if necessary, the
crankshaft may be reground to restore the
journals. Generally, the valves are serviced as
well, since they’re usually in less-than-perfect
condition at this point. While the engine is
being overhauled, other components, such as
the distributor, starter and alternator, can be
rebuilt as well. The end result should be a like
new engine that will give many trouble free
miles. Note:Critical cooling system
components such as the hoses, drivebelts,
thermostat and water pump should be
replaced with new parts when an engine is
overhauled. The radiator should be checked
carefully to ensure that it isn’t clogged or
leaking (see Chapter 3).If you purchase a
2.4a The oil pressure sender unit (arrowed)
is located in the right front corner of the
engine block, near the oil filter2.4b The oil pressure can be checked by
removing the sender unit and refitting a
pressure gauge in its place