VIN JAGUAR XJ6 1997 2.G Owner's Manual

Refitting
7Use a scraper to remove all traces of old
gasket material and carbon deposits from the
manifold and cylinder head mating surfaces. If
the gasket was leaking, have the manifold
checked for warpage at an automotive
machine workshop and resurfaced if
necessary.
8Position new gaskets over the cylinder
head studs (see illustration). Note:The
marks on the gasket should face out (away
from the cylinder head) and the arrow should
point toward the rear of the engine.
9Refit the manifolds and thread the mounting
nuts/bolts into place.
10Working from the centre out, tighten the
nuts/bolts to the torque listed in this Chapter’s
Specifications in three or four equal steps.
11Refit the remaining parts in the reverse
order of removal.
12Run the engine and check for exhaust
leaks.
7 Crankshaft front oil seal-
renewal
3
1Disconnect the negative cable from the
battery.
Caution: If the stereo in your vehicle isequipped with an anti-theft system, make
sure you have the correct activation code
before disconnecting the battery.
2Refer to Chapter 1 and remove the
accessory drive belts.
3Refer to Chapter 3 and remove the fan
shroud and fan clutch assembly.
4Remove the crankshaft damper bolt with a
socket and large breaker bar (see illustration).
To hold the crankshaft stationary, remove the
flywheel inspection cover (see Chapter 8) and
wedge a large screwdriver into the flywheel
ring gear teeth. Warning: The damper bolt is
under considerable torque, so
be sure the socket is firmly in
place and that your hands are
not in danger of hitting anything sharp.
5Use a bolt-type damper puller (available at
most car accessory outlets) to remove the
crankshaft damper (see illustration).
7Remove the Woodruff key from the
crankshaft keyway (see illustration).
8Carefully pry the seal out of the front cover
with a screwdriver or seal-removal tool(see
illustration). Don’t scratch the bore or
Engine in-car repair procedures 2A•5
2A
6.3 Remove nuts (small arrows) retaining
the exhaust pipe to the manifold flanges;
two for each pipe - larger arrow indicates
one heat shield bolt accessible from below6.4 Remove the upper heat shield bolts
(arrowed)6.6 Remove the bolts and nuts and
remove the front and rear exhaust
manifolds
6.8 Refit new gaskets in position over the
studs with the markings facing out
7.7 Carefully tap one end the Woodruff key
up and out from the crankshaft keyway,
then grasp it with a pair of locking pliers
and pull it the rest of the way out - be
careful not to damage the key or keyway7.8 Remove the crankshaft seal with a
screwdriver or seal puller - there are two
slots (arrowed) in the cover which allow
you to pry behind the seal
7.4 Use a large breaker bar and the
appropriate size socket to remove the
crankshaft pulley bolt7.5 After removing the centre bolt, remove
the crankshaft damper with a two-bolt
puller - be careful not to damage the
sensor ring
3261 Jaguar XJ6

damage the crankshaft in the process (if the
crankshaft is damaged, the new seal will end
up leaking).
9The crankshaft seal rides on a spacer that
slips over the front of the crankshaft. Slip the
spacer off and clean the varnish off the seal
surface (see illustration).
10Clean the bore in the cover and coat the
outer edge of the new seal with engine oil or
multi-purpose grease. Apply moly-base
grease to the seal lip.
11Lubricate the spacer with clean engine oil
and refit it onto the crankshaft. Using a socket
with an outside diameter slightly smaller than
the outside diameter of the seal, carefully
drive the new seal into place with a hammer
(see illustration). Make sure it’s installed
squarely and driven in to the same depth as
the original. If a socket isn’t available, a short
section of large-diameter pipe will also work.
Note:The new seal comes with a plastic
installer guide. Do not remove this guide until
refitting is completed. The guide keeps the
seal lip properly oriented over the crankshaft.
12Refit the Woodruff key, then refit the
damper. Tighten the damper bolt to the
torque listed in this Chapter’s Specifications.
Note:The damper bolt can be used to pull the
damper back onto the crankshaft, but make
sure the damper is perfectly aligned with the
Woodruff key.
13The rest of the assembly is the reverse of
the removal procedure.
14Run the engine and check for oil leaks at
the front seal.
8 Timing chains
and sprockets- removal,
inspection and refitting
3
Caution: If the timing chain broke during
engine operation, the valves may have
come in contact with the pistons, causingdamage. Check the valve clearance (see
Section 10) before removal of the cylinder
head - bent valves usually will have
excessive clearance, indicating damage
that will require machine workshop work to
repair.
Note 1:This procedure requires that the sump
be removed (see Section 12).In a professional
workshop, this would be performed as an in-
car procedure with specialised tools to
remove the front suspension. Given the
equipment available to the average home
mechanic, this alternate procedure requires
removal of the engine from the car.
Note 2:If your engine is a 4.0 litre, built after
serial number 9J160552, and you’re
experiencing an engine rattle on cold starts
that disappears after the engine is warmed up,
the problem could be a defective upper
tensioner. A newly designed replacement
upper tensioner is available from the dealer
and should solve the problem. It can be
installed easily without pulling the cylinder
head or front cover, or can be installed during
a chain removal procedure.
Removal
1Disconnect the negative cable from the
battery.
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.
2Block the rear wheels and set the
handbrake.
3Refer to Part B of this Chapter for engine
removal procedures.
4Refer to Section 4 and remove the valve
cover.
5Refer to Section 3 and position the engine
at TDC for cylinder number 1, then mark and
remove the distributor (see Chapter 5).
6Refer to Section 11 and remove the cylinder
head. After cylinder head removal, the uppertiming chain will be loosely retained by the
two upper chain guides, which are retained by
refitting a large rubber band (see Section 10).
Caution: Do not rotate the crankshaft with
the upper timing chain disconnected and
the cylinder head and camshafts in place,
or damage could result from piston-to-
valve contact.
7Some models may be equipped with a
hydraulic pump used for the brake
servo/hydraulic self-levelling suspension
system. If equipped, it will be mounted to the
front cover. Models not equipped with this
option will have a flat block-off plate over the
hole. If equipped with the pump, refer to
Chapters 9 and 10 for procedures to reduce
the high pressure in the brake servo system
and to depressurise the self-levelling system.
Before removing the engine, unbolt the pump
from the front cover and set it aside without
disconnecting the hoses (see illustration).
8Refer to Section 7 and remove the
crankshaft pulley and damper. Refer to
Section 12 for removal of the sump.
9If equipped with the hydraulic pump,
remove the coupling disc and unbolt the drive
coupling from the intermediate shaft (see
illustrations).
2A•6 Engine in-car repair procedures
8.7 Unbolt the hydraulic pump (arrowed)
from the front cover, without
disconnecting the hoses
3261 Jaguar XJ6 7.9 Remove the spacer from the end of the crankshaft
and clean it thoroughly
7.11 Drive the new seal squarely into the front cover with a large
socket or section of pipe - do not remove the plastic refitting
guide (arrowed) until the seal is installed

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

12Remove the four bolts in each camshaft
inner sprocket (see illustration). The bolts are
secured by sheetmetal “washer” plates. Bend
down the locking tabs with a hammer and
screwdriver tip to remove the bolts.
Caution: Stuff rags below the sprockets
while removing the bolts to prevent a bolt
from falling down into the front cover.
13Remove the two bolts retaining the upper
chain guide to the cylinder head (see
illustration).
14Pull the inner sprockets from each
camshaft (see illustration). Each camshaft
sprocket is comprised of an inner and outer,
each with a set of fine splines that lock them
together. The outer sprockets, with the teeth,
can rotate on the camshafts until the inner
sprocket bolts are tightened.
15Pull the outer sprockets from the
camshafts and allow the chain slacken.
16At this point the camshafts can be
carefully lifted straight up and off the cylinder
head. Take care not to nick any of the lobes or
journals during removal.
17Use a magnet to remove the lifters,
keeping them in order in a divided, numbered
box (see illustration). They must be returned
to their original location if reusing the original
camshafts!
18Removing the lifters exposes the
adjusting shims, sitting in a pocket in eachvalve spring retainer (see illustration). Keep
the shims with their matching lifters. Measure
the thickness of each shim with a micrometer
and record the measurements.
Inspection
19After the camshaft has been removed
from the engine, cleaned with solvent and
dried, inspect the bearing journals for uneven
wear, pitting and evidence of seizure. If the
journals are damaged, the bearing surfaces in
the cylinder head and caps may be damaged
as well, requiring renewal of the cylinder head.
20Measure the bearing journals with a
micrometer to determine if they are excessivelyworn or out-of-round (see illustration).
Compare the measurements to Specifications.
21Check the camshaft lobes for heat
discolouration, score marks, chipped areas,
pitting and uneven wear. Measure the lobe
heights with a micrometer and record the
measurements (see illustrations). If there is
variance of more than 0.005-inch, the
camshaft and lifters must be renewed. If the
lobes are in good condition, the camshaft can
be reused.
22Inspect the top, bottom and side surfaces
of the lifters for wear, grooving or scoring. If
the lifters are damaged, the camshaft and its
lifters must be renewed as a set.
Engine in-car repair procedures 2A•11
2A
10.13 Remove the two bolts and the upper
timing chain guide (arrowed)10.14 Pull the inner sprocket from the
outer sprocket of each camshaft
10.17 A magnet can be used to remove
the lifters (arrowed)10.18 The valve adjustment shims
(arrowed) fit into a pocket in the valve
spring retainer - use a magnet to remove
the shims and keep them with their
respective lifters10.20 Measure the bearing journals with a
micrometer to check diameter - measure
at several places around the journal to
check for taper or out-of-round
3261 Jaguar XJ6 10.12 Bend back the locking tabs
(arrowed) and remove the camshaft
sprocket bolts
10.21a Measure the camshaft lobe at its
greatest dimension . . .10.21b . . . and subtract the camshaft lobe
diameter at its smallest dimension to
obtain the lobe lift

Refitting
5Remove all traces of old gasket material
and sealant from the engine block and sump.
Clean the mating surface with lacquer thinner
or acetone.
Caution: Do not use a sharp scraping tool.
Both the sump and the engine block are
aluminium and could be easily damaged.
6Make sure the threaded bolt holes in the
engine block and bellhousing are clean.
7Inspect the flange of the sump for any
cracks, pits or scratches that could cause an
oil leak.
8Remove the baffle plate at the rear of the
sump (see illustration). Clean the sump area
and the baffle, then refit the baffle.
9Inspect the oil pump pickup tube for
cracks, or foreign material blocking the screen
(see illustration).
10Apply a bead of RTV sealant to the sump
flange(see illustration). Note:The sump
must be installed within 5 minutes of sealer
application.
11Carefully position the sump on the engine
block and push it toward the transmission
adapter plate as you press it against the
engine block. Loosely refit four bolts, two on
each side of the sump. Tighten the four bolts
in a criss-cross pattern to the torque listed in
this Chapter’s Specifications, then loosen
each bolt 90°.
12Refit the two engine adapter-to-sump
bolts. Tighten the two bolts to the torque
listed in this Chapter’s Specifications, then
loosen each one 180°.
13Refit the remainder of the sump-to-engine
block bolts hand tight until all are installed,
then tighten them to the torque listed in this
Chapter’s Specifications. Lastly, tighten the
two adapter-to-sump bolts to the torque
listed in this Chapter’s Specifications.
Caution: Failure to follow this tightening
procedure could stress or possibly crack
the adapter plate.
14The remainder of refitting is the reverse of
removal. Be sure to add oil and refit a new oil
filter.
15Run the engine and check for oil pressure
and leaks.13 Oil pump- removal,
inspection and refitting
4
Removal
1Remove the sump (see Section 12).
2Unbolt the oil pickup tube and oil transfer
housing from the engine block (see
illustration). Note:Have a drain pan under the
transfer housing, as oil may drip out when the
housing is loosened from the engine block.
3Carefully pull the transfer housing and
transfer tubes to the rear to separate them
from the oil pump body.
4Bend back the locking tabs and remove thethree bolts retaining the oil pump drive
sprocket to the oil pump (see illustration).
Pull the chain and sprocket from the front of
the pump. Note:There are shims between the
sprocket and the pump. Collect them while
pulling off the sprocket.
5Remove the bolts and detach the oil pump
from the engine.
6Remove all traces of sealant and old gasket
material from the oil pump body and engine
block, then clean the mating surfaces with
lacquer thinner or acetone.
7Remove the screws and separate the front
and rear pump covers from the body. Lift out
the drive and driven rotors (see illustrations).
Note:Mark the front face of each rotor before
removing them.
Engine in-car repair procedures 2A•15
2A
12.8 Remove the bolts (arrowed) and the
sheetmetal baffle plate - clean the sump
area of the sump with the baffle removed12.9 Lubrication system components
A Oil pump
B Transfer tubesC Transfer housing
D Oil pump pickup12.10 Apply a bead of RTV sealant around
the perimeter of the sump mounting
flange, be sure to run the bead around the
outside all bolt the holes
13.7a Remove the bolts and separate the
front and rear pump covers13.7b Remove the outer rotor (A)
and inner rotor (B)
13.2 Unbolt the oil pump pickup (A) and
the bolts (B) retaining the transfer
assembly (C) to the engine block13.4 Pry back the locking tabs and remove
the three bolts retaining the oil pump drive
sprocket to the pump
3261 Jaguar XJ6

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

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

rebuilt engine or short block, some rebuilders
will not warranty their engines unless the
radiator has been professionally flushed. Also,
we don’t recommend overhauling the oil
pump - always refit a new one when an engine
is rebuilt.
Before beginning the engine overhaul, read
through the entire procedure to familiarise
yourself with the scope and requirements of
the job. Overhauling an engine isn’t difficult,
but it is time-consuming. Plan on the vehicle
being tied up for a minimum of two weeks,
especially if parts must be taken to an
automotive machine workshop for repair or
reconditioning. Check on availability of parts
and make sure that any necessary special
tools and equipment are obtained in advance.
Most work can be done with typical hand
tools, although a number of precision
measuring tools are required for inspecting
parts to determine if they must be renewed.
Often an automotive machine workshop will
handle the inspection of parts and offer
advice concerning reconditioning and
renewal. Note:Always wait until the engine
has been completely dismantled and all
components, especially the engine block,
have been inspected before deciding what
service and repair operations must be
performed by an automotive machine
workshop. Since the engine block’s condition
will be the major factor to consider when
determining whether to overhaul the original
engine or buy a rebuilt one, never purchase
parts or have machine work done on other
components until the engine block has been
thoroughly inspected. As a general rule, time
is the primary cost of an overhaul, so it
doesn’t pay to refit worn or substandard
parts.
If it turns out that a number of major
components are beyond reconditioning, it
may be cost effective to buy a factory-rebuilt
engine from a Jaguar dealership.
As a final note, to ensure maximum life and
minimum trouble from a rebuilt engine,
everything must be assembled with care in a
spotlessly-clean environment.
3 Vacuum gauge
diagnostic checks
2
A vacuum gauge provides valuable
information about what is going on in the
engine at a low cost. You can check for worn
rings or cylinder walls, leaking cylinder head or
intake manifold gaskets, incorrect carburettor
adjustments, restricted exhaust, stuck or
burned valves, weak valve springs, improper
ignition or valve timing and ignition problems.
Unfortunately, vacuum gauge readings are
easy to misinterpret, so they should be used
with other tests to confirm the diagnosis.
Both the absolute readings and the rate of
needle movement are important for accurate
interpretation. Most gauges measure vacuumin inches of mercury (in-Hg). As vacuum
increases (or atmospheric pressure decreases),
the reading will decrease. Also, for every
1000 foot increase in elevation above sea level;
the gauge readings will decrease about one
inch of mercury.
Connect the vacuum gauge directly to
intake manifold vacuum, not to ported (above
the throttle plate) vacuum (see illustration).
Be sure no hoses are left disconnected during
the test or false readings will result.
Before you begin the test, allow the engine
to warm up completely. Block the wheels and
set the handbrake. With the transmission in
Park, start the engine and allow it to run at
normal idle speed.
Warning: Carefully inspect the
fan blades for cracks or damage
before starting the engine. Keep
your hands and the vacuum
tester clear of the fan and do not stand in
front of the vehicle or in line with the fan
when the engine is running.
Read the vacuum gauge; an average,
healthy engine should normally produce
between 17 and 22 inches of vacuum with a
fairly steady needle.
Refer to the following vacuum gauge
readings and what they indicate about the
engines condition:
1A low steady reading usually indicates a
leaking gasket between the intake manifold
and carburettor or throttle body, a leaky
vacuum hose, late ignition timing or incorrect
camshaft timing. Check ignition timing with a
timing light and eliminate all other possible
causes, utilising the tests provided in this
Chapter before you remove the timing belt
cover to check the timing marks.
2If the reading is three to eight inches below
normal and it fluctuates at that low reading,
suspect an intake manifold gasket leak at an
intake port or a faulty injector.
3If the needle has regular drops of about two
to four inches at a steady rate the valves are
probably leaking. Perform a compression or
leak-down test to confirm this.
4An irregular drop or down-flick of the
needle can be caused by a sticking valve or
an ignition misfire. Perform a compression or
leak-down test and read the spark plugs.5A rapid vibration of about four in-Hg
vibration at idle combined with exhaust
smoke indicates worn valve guides. Perform a
leak-down test to confirm this. If the rapid
vibration occurs with an increase in engine
speed, check for a leaking intake manifold
gasket or cylinder head gasket, weak valve
springs, burned valves or ignition misfire.
6A slight fluctuation, say one inch up and
down, may mean ignition problems. Check all
the usual tune-up items and, if necessary, run
the engine on an ignition analyser.
7If there is a large fluctuation, perform a
compression or leak-down test to look for a
weak or dead cylinder or a blown cylinder
head gasket.
8If the needle moves slowly through a wide
range, check for a clogged PCV system,
incorrect idle fuel mixture, throttle body or
intake manifold gasket leaks.
9Check for a slow return after revving the
engine by quickly snapping the throttle open
until the engine reaches about 2,500 rpm and
let it shut. Normally the reading should drop to
near zero, rise above normal idle reading
(about 5 in.-Hg over) and then return to the
previous idle reading. If the vacuum returns
slowly and doesn’t peak when the throttle is
snapped shut, the rings may be worn. If there
is a long delay, look for a restricted exhaust
system (often the silencer or catalytic
converter). An easy way to check this is to
temporarily disconnect the exhaust ahead of
the suspected part and redo the test.
4 Cylinder compression check
2
1A compression check will tell you what
mechanical condition the upper end (pistons,
rings, valves, cylinder head gasket) of your
engine is in. Specifically, it can tell you if the
compression is down due to leakage caused
by worn piston rings, defective valves and
seats or a blown cylinder head gasket. Note:
The engine must be at normal operating
temperature and the battery must be fully
charged for this check.
2Begin by cleaning the area around the
spark plugs before you remove them
(compressed air should be used, if available,
otherwise a small brush or even a bicycle tyre
pump will work). The idea is to prevent dirt
from getting into the cylinders as the
compression check is being done.
3Remove all of the spark plugs from the
engine (see Chapter 1).
4Block the throttle wide open.
5Detach the coil wire from the centre of the
distributor cap and ground it on the engine
block. Use a jumper wire with alligator clips on
each end to ensure a good earth. Also,
remove the fuel pump relay (see Chapter 4) to
disable the fuel pump during the compression
test.
Engine removal and overhaul procedures 2B•3
2B
3.4 The vacuum gauge is easily attached
to a port on the intake manifold, and can
tell a lot about an engine’s state of tune
3261 Jaguar XJ6

6Refit the compression gauge in the spark
plug hole (see illustration).
7Crank the engine over at least seven
compression strokes and watch the gauge.
The compression should build up quickly in a
healthy engine. Low compression on the first
stroke, followed by gradually increasing
pressure on successive strokes, indicates
worn piston rings. A low compression reading
on the first stroke, which doesn’t build up
during successive strokes, indicates leaking
valves or a blown cylinder head gasket (a
cracked cylinder head could also be the
cause). Deposits on the undersides of the
valve heads can also cause low compression.
Record the highest gauge reading obtained.
8Repeat the procedure for the remaining
cylinders and compare the results to this
Chapter’s Specifications.
9Add some engine oil (about three squirts
from a plunger-type oil can) to each cylinder,
through the spark plug hole, and repeat the
test.
10If the compression increases after the oil
is added, the piston rings are definitely worn.
If the compression doesn’t increase
significantly, the leakage is occurring at the
valves or cylinder head gasket. Leakage past
the valves may be caused by burned valve
seats and/or faces or warped, cracked or bent
valves.
11If two adjacent cylinders have equally low
compression, there’s a strong possibility that
the cylinder head gasket between them is
blown. The appearance of coolant in the
combustion chambers or the crankcase
would verify this condition.
12If one cylinder is 20 percent lower than the
others, and the engine has a slightly rough
idle, a worn exhaust lobe on the camshaft
could be the cause.
13If the compression is unusually high, the
combustion chambers are probably coated
with carbon deposits. If that’s the case, the
cylinder head(s) should be removed and
decarbonised.
14If compression is way down or varies
greatly between cylinders, it would be a goodidea to have a leak-down test performed by
an automotive repair workshop. This test will
pinpoint exactly where the leakage is
occurring and how severe it is.
5 Engine removal-
methods and precautions
If you’ve decided that an engine must be
removed for overhaul or major repair work,
several preliminary steps should be taken.
Locating a suitable place to work is
extremely important. Adequate work space,
along with storage space for the vehicle, will
be needed. If a workshop or garage isn’t
available, at the very least a flat, level, clean
work surface made of concrete or asphalt is
required.
Cleaning the engine compartment and
engine before beginning the removal
procedure will help keep tools clean and
organised.
An engine hoist or A-frame will also be
necessary. Make sure the equipment is rated
in excess of the combined weight of the
engine and transmission. Safety is of primary
importance, considering the potential hazards
involved in lifting the engine out of the vehicle.
If the engine is being removed by a novice,
a helper should be available. Advice and aid
from someone more experienced would also
be helpful. There are many instances when
one person cannot simultaneously perform all
of the operations required when lifting the
engine out of the vehicle.
Plan the operation ahead of time. Arrange
for or obtain all of the tools and equipment
you’ll need prior to beginning the job. Some of
the equipment necessary to perform engine
removal and refitting safely and with relative
ease are (in addition to an engine hoist) a
heavy duty trolley jack, complete sets of
spanners and sockets as described in the
front of this manual, wooden blocks and
plenty of rags and cleaning solvent for
mopping up spilled oil, coolant and petrol. If
the hoist must be rented, make sure that you
arrange for it in advance and perform all of the
operations possible without it beforehand.
This will save you money and time.
Plan for the vehicle to be out of use for
quite a while. A machine workshop will be
required to perform some of the work which
the do-it-yourselfer can’t accomplish without
special equipment. These shops often have a
busy schedule, so it would be a good idea to
consult them before removing the engine in
order to accurately estimate the amount of
time required to rebuild or repair components
that may need work.
Always be extremely careful when removing
and refitting the engine. Serious injury can
result from careless actions. Plan ahead, take
your time and a job of this nature, although
major, can be accomplished successfully.
6 Engine- removal and refitting
3
Note:Read through the entire Section before
beginning this procedure. It is recommended
to remove the engine and transmission from
the top as a unit, then separate the engine
from the transmission on the workshop floor. If
the transmission is not being serviced, it is
possible to leave the transmission in the
vehicle and remove the engine from the top by
itself, by removing the crankshaft damper and
tilting up the front end of the engine for
clearance,but access to the upper
bellhousing bolts is only practical when the
rear transmission mount and driveshaft have
been removed and the transmission is angled
down with a trolley jack.
Removal
1Relieve the fuel system pressure (see
Chapter 4).
2Disconnect 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.
3Place protective covers on the wings and
cowl and remove the bonnet (see Chapter 11).
4Remove the battery and battery tray.
5Remove the air cleaner assembly (see
Chapter 4).
6Raise the vehicle and support it securely on
axle stands. Drain the cooling system and
engine oil and remove the drivebelts (see
Chapter 1).
7Clearly label, then disconnect all vacuum
lines, coolant and emissions hoses, wiring
harness connectors and earth straps.
Masking tape and/or a touch up paint
applicator work well for marking items (see
illustration). Take instant photos or sketch
the locations of components and brackets.
8Remove the cooling fan(s) and radiator (see
Chapter 3).
9Disconnect the heater hoses.
10Release the residual fuel pressure in the
tank by removing the petrol cap, then detach
the fuel lines connecting the engine to the
chassis (see Chapter 4). Plug or cap all open
fittings.
2B•4 Engine removal and overhaul procedures
4.6 A compression gauge with a threaded
fitting for the spark plug hole is preferred
over the type that requires hand pressure
to maintain the seal - be sure to block
open the throttle valve as far as possible
during the compression check!
6.7 Label both ends of each wire and hose
before disconnecting it
3261 Jaguar XJ6