1994 JAGUAR XJ engine

AJ16 Engine Service Manual
0 Application Item
'rimary timing chain Type
Pitch
Roller diameter
secondan/ timing chain Type
Number of pitches
Pitch
Number of
pitches Specification
Endless duplex
80
9,525
mm
6,35 mm
Endless duplex
86
9,525
mm
lil pump chain
lil filter
lil pressure (engine at normal
,perati ng temperature)
Si1 pump
I Roller diameter 16,35 mm
I Type I Endless simplex
Roller diameter
6,35 mm
Deflection (at mid-point of free side) 2 to 4 mm (with a load of 50 N)
Type Full flow disposable canister
At
idle speed 0,5 bar (minimum)
At
4000 RPM 4,83 bar (minimum)
Type Rotor
Rotor end float
0,l mm
Number of pitches I52
Pitch 19,525 mm
___ Overall length
Working length Mandrel length
Mandrel diameter 35 mm
30 mm
57 mm
11,ll mm
Si1 pressure relief valve
Application
Generator
/ water pump drive belt (normally aspirated
engines)
Generator
/ water pump drive belt (4.0 liter
supercharged engine)
I Rotor lobe clearance 10,2 mm I
Specification
Burroughs method: new belt
556 to 578 N. Run for one
minute, allow belt to cool and reset to the in
-service
setting. In service if tension falls below
356 N, reset at
511 to 534 N
.Clavismethod: new belt 174 to 180 Hz. Run for one
minute, allow belt to cool and reset to the in
-service
setting. In service
if tension falls below 140 Hz, reset at 167 to 173 Hz. (Measuring point: mid-way between
crankshaft and generator pulleys)
Burroughs method: new belt
560 to 600 N. Run for one
minute, allow belt to cool and reset to the in
-service
setting. In service if tension falls below
335 N, reset at
405 to 445 N
Clavis method: new belt
180 to 186 Hz. Run for one
minute, allow belt to cool and reset to
the in-service
setting. In service if tension falls below
131 Hz, reset at
155 to 161 Hz. (Measuring point: mid-way between
crankshaft and generator pulleys)
__ ___
.- ...
pket she sizes ___ Outside diameter
1
1
Drive Belt Tensions
0
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AJ16 Engine Service Manual
Application
4ir conditioning compressor drive belt
Supercharger drive belt Specification
Burroughs method: new belt 556 to 578 N (no
retensioning required). In service
if tension falls below
245
N, reset at 378 to 400 N
Clavis method: new belt 167 to 173 Hz (no retensioning
required). In service if tension falls below 85 Hz, reset
at 127 to 133
Hz. (Measuring point: mid-way between
crankshaft and compressor pulleys)
Burroughs method: new belt
993 to 1033 N. Drive the
vehicle for
10 minutes, allow the belt to cool to ambient
(approximately one hour) and reset to the in
-service
setting. In service
at 16000 kilometer (10000 mile)
intervals, reset at 835 to 875
N with the belt cold.
Renew belt at 48000 kilometer (30000
mile) intervals
Clavis method: new belt 119 to 121
Hz. Drive the
vehicle for
10 minutes, allow the belt to cool to ambient
(approximately one hour) and reset to the in
-service
setting.
In service at 16000 kilometer (10000 mile)
intervals, reset
at 11 1 to 113 Hz with the belt cold.
Renew belt at 48000 kilometer (30000 mile) intervals.
(Measuring point mid
-way between crankshaft and
supercharger pulleys)
xvii Issue 1 August 1994

AJ16 Engine Service Manual
0 GENERAL DESCRIPTION - The engine is available as a 3,2 and 4,O liter unit. A 4,O liter supercharged version is also available. Fuel is supplied
to each cylinder via an injector fed from a regulated fuel rail. To comply with statutory regulations in some countries
and to reduce emissions during the warm
-up period, secondary air is delivered to the exhaust manifold by an electri- cally operated air injection pump. This improves oxidation until the catalytic converters are fully effective. All engine
functions are controlled by an integrated engine management system, which incorporates the on-board diagnostic
system (OBDII).
1.1 Construction
The skirted design crankcase is manufactured in cast aluminum alloy with shrink fit dry cast iron cylinder sleeves.
Thecrankshaft ismanufactured from cast
ironforthe3,2 literengine,forged steel forthe 4,O liter engineand is nitro-car-
burize treated to give a very high quality finish on the bearing surfaces and increase the life of the journals.
The crankshaft is supported by seven iron bearing caps having bearings, which are lead bronze on split steel backed
shells with a lead indium overlay.
Crankshaft end
-float is controlled by half thrust washers fitted on each side of the center main bearing journal. The
connecting rods are manufactured from carbon manganese steel, forged in an 'H' section. The small end bushes are
lead bronze with steel backing, machined to size after being pressed into the connecting rods. The connecting rod bear- ings are of a lead bronze alloy on split steel backed shells and with lead indium overlay.
The pistons are of monometal construction (aluminum) and have a spring assisted micro
-land oil control ring situated
below a barrel-faced internally tapered chrome plated compression ring and an externally stepped taper-faced second-
ary ring.
The cylinder head is cast from aluminum alloy with pent
-roof shaped combustion chambers with cross-flow valve
porting. Running directly in the cylinder head are
twocast iron camshafts retained by machined aluminumcaps. Each
camshaft uses chilled cams to drive two valves per cylinder via chilled cast iron bucket tappets with shim adjustment.
Control of each of the four valves per cylinder is maintained by single valve springs.
The camshafts are operated by a two stage 'duplex' chain drive from the crankshaft. Each stage is controlled by a hy
- draulic tensioner operating through a pivoted rubber-faced curved tensioner blade. The first stage incorporates a three
point drive via the crankshaft, intermediate shaft and auxiliary shaft. The intermediate shaft is live and provides a 0.75 x crank speed drive through the timing cover. This drive access is blanked off. The 'live' auxiliary shaft is driven at
crankshaft speed and is situated on the right hand side of the engine (looking from rear). In addition to driving the
engine position sensor via a set of 2 : 1 reduction spiral gears, it provides an external drive for the power assisted steer- ing pump at the rear. The second stage is a three point drive via the intermediate shaft and two camshafts. The 2:l reduction ratio from crank speed is achieved by the combined ratio of the intermediate and camshaft sprockets sizes.
The oil pump is a rotor
-type mounted on the underside of the front of the crankcase and driven by a 'simplex' chain
from the crankshaft nose. The pump incorporates a built-in pressure relief valve. Below the line of the crankcase, but
abovetheoil pan
oillevel aretwowindagetrays; these prevent oil beingsucked upand thrown into thecrankcasethere- by alleviating windage and power losses through oil surge.
At the rear of the crankshaft is
a new design of lip-type PTFE oil seal which provides a high degree of oil retention. It also allows the use of higher engine speeds and easier serviceability.
1.2 Cylinder Head Design
The four valves per cylinder are smaller in diameter than on a conventional two valve per cylinder engine and have a greater combined effective area. They are also lighter and apply less stress to the operating gear. The design in- creases the power at high engine speeds and allows an efficient combustion of the fuel. It also allows the spark plug
to besituated in its ideal central position which creates efficient combustion and consequently enhancesfuel economy.
1.3 Crankcase Breather
Blow-by gases are recycled via the air intake system to maintain a crankcase depression and so prevent their escape
to the atmosphere. A baffled vent from the camshaft cover is used for both full and part load breathing. For full load
breathing,
a connection is made direct to the clean side ofthe air filter upstream ofthe throttle disc. Part load breathing is provided by a spur off the full load pipe to downstream ofthe throttle disc via the water heated restrictor. In this way,
a crankcase depression is maintained at all throttle settings.
1.4 Lubrication System
Oil is drawn from the oil pan via a gauze filter. Pressurized oil, having been regulated by a relief valve, is then fed via
internal galleries on the left hand side of the cylinder block. Pressurized and filtered oil is fed into the main oil gallery,
the seven main bearings are fed and thence via crankshaft drillings to the connecting rod bearings. The intermediate
shaft, auxiliary shaft and camshaft bearings are pressure lubricated by means of internal drillings directly fed from the
front of the main oil gallery. For some markets an oil cooler is fitted to vehicles with
4,O liter supercharged engines.
The pistons run on hardened steel piston pins offset from the center line of the piston towards the thrust face.
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AJ16 Engine Service Manual
1.5 Coohg System
The engine is liquid cooled by a mixture of water and anti-freeze circulating around the coolant passages. The coolant
pump is mounted on the left hand side of the cylinder block and is driven from the crankshaft nose by a three point
belt drive (which includes the generator). The pump is a fully assembled bolt
-on unit. The coolant is fed into the cylin- der block at two places via an external delivery pipe. The coolant is drawn from the cylinder head via a self-contained
thermostat housing back to the radiator or recirculated according to the thermostat position.
7.6 Supercharger
The supercharger optionally available on the 4,O liter engine is a Roots blower type which gives better engine efficiency
at part throttle conditions and responsive off
-boost performance. The principal changes to the engine for the super- charged version are to the piston, valve timing, intake manifold and the additional drive to the supercharger. A lower
compression ratio
of 8.5:l is used which provides the optimum balance between high speed performance and fuel
economy.
The engine heat exchanger of the intercooler system is incorporated into the intake manifold. The blower incorporates
an air by
-pass system which improves efficiency under part throttle conditions. The by-pass valve is controlled by a vacuum actuator referenced to the intake manifold pressure.
2. SERVICE PROCEDURES
2.1 SPS )oint Control System
Afeature of the engine is the use of the SPS joint control system on the cylinder head bolts, crankshaft main bearing
bolts and connecting rod bearing nuts and bolts. This system ensures that the joints receive maximum clamp loading
for a given fixing size and type of material by tightening the fixing to its particular yield point. This greatly helps to
prevent premature cylinder head gasket failures.
0
CAUTION: All SPS fixings must be used only once. Discard
fixings on removal and replace with new bolts/
nuts every time a 'strip down' has been carried
out.
The SPS system in service requires the fixing to be
set to a specific torque initially; it must then be ro
- tated through 90 degrees exactly. The accuracy of
thiscannot betoo highlystressed. Toobtainthecor- rect setting, use Special Tool LST 122, or a self-man-
ufactured tool using the dimensions illustrated (Fig.
I).
SeeTorqueTightening Specifications in the Prelimi-
nary Pages for the correct torque figures.
b:
w:
2.2 Sealants
One of the specified sealants for use on this engine is the Marston compound known as Hylosil 102, a white amine cure
system rubber. Should this not be available an equivalent amine cure sealant must be used. Under no circumstances
should any acidtoxy cure system be used. Loctite sealants are specified for certain applications. See Service Materials
in the Preliminary Pages for the correct sealant for each application.
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AJ16 Engine Service Manual
FAULT DIAGNOSIS
3.1 Introduction
The following diagnostic procedures are provided to assist properly qualified persons to identify and rectify the faults
relating to the engine which are most likely to encountered. Reference is made to the Electrical Diagnostic Manual
(EDM), which should be consulted where necessary. Faults related to the cooling system are dealt with in Section 4.1
and to the fuel system in Section 5.1 in the appropriate Vehicle Service Manual (VSM).
3.2 Diagnostic Procedures
(fails to rotate)
I Engine rotates but 0 I will not fire
I
i
/Overheating
Overheating at tick-
Too cold
Loss of coolant Possible
Cause
Battery leads loose or ter
- minals corroded
Battery discharged
Starter motor inoperative
Starter motor speed too
low
Faulty ignition system
Fuel system defect
Oil requires changing
Worn crankshaft journals
Excessive crankshaft
end- float
Worn main bearing shells
Worn oil pump Oil pressure relief valve stick
- ing open
Oil pressure relief valve
spring too weak
Insufficient oil in oil pan
Engine overheating
Faulty gauge or sensor
Incorrect grade oil (viscosity
too low)
Water in oil Check
Check the condition of the
leads and terminals
Check condition of battery
with hydrometer
If the lights dim when ignition
switch is operated, the starter
may be jammed in starter
ring.
Check for loose and dirty con
- nections to the starter motor
Check battery leads and ter
- minals
Check state of battery charge
Refer to EDM
Remove the spark plugs
Check oil level and color
Listen for rumble or knock
Fit dial gauge and measure
Listen for rumble
Remove oil pump and check
the clearances
Remove valve and check for
sticking
Remove spring and check
spring rates
Check oil level
Refer to EDM
Check oil viscosity
Checkoil level and check if oil
is a milky white color
Check for leaking head gasket Remedy
Clean and tighten as necess
-
ary
Charge or renew battery as
necessary
Remove starter motor, free
off pinion and refit
Clean and tighten connec
- tions
Clean and tighten terminals
Charge or renew battery
as necessary
Rectify as required
Clean and re
-gap the spark
plugs, renew if worn out
Refer to Fuel System fault
finding in Section
5.1, VSM
Refer to Section
4.1, VSM
Refer to Section
4.1, VSM
Refer to Section
4.1, VSM
Refer to Section
4.1, VSM
Change oil and filter
Renew crankshaft
Renew thrust washers
Check crankshaft journals for
wear and renew shells
Renew oil pump
Renew valve
Renew spring
lop-up as required
Refer to Overheating fault
finding in Section
4.1, VSM
Rectify as required
Renew oil and filter
Renew oil and filter
Renew head gasket
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AJ16 Engine Service Manual
Symptom Possible Cause ~~
nsufficient
oil pres- ure (continued)
lil pressure too high
3urning oil
.osing oil (leaking)
Excessive noise
'rom valve gear Cracked
oil pump housing
Blocked oil pick
-up pipe
strainer
Oil pump pipe
'0' rings
Main oil gallery seals leaking
or gallery blocked
Relief valve stuck shut
Wrong pressure relief valve
Incorrect grade engine oil
(viscosity too high)
Gauge or sensor fault
Engine temperature too low
Worn cylinder bores
Worn valve guides
Worn intake valve seals
Worn piston rings
Cylinder head gasket leaking
Incorrect grade of engine oil
Worn front oil seal
Worn rear oil seal
Leaking gaskets
Cylinder block cracked
Excessive valve clearance
Broken valve
spring(s)
Broken valve guide
Broken valve seat insert
Lack of lubrication
Valve clash
Worn
camshaft(s)
Worn camshaft drive chains i tensioners
Check
Remove oil pan and visually
check
Remove oil pan and visually
check
Removeoil
panand pipesand check Eliminate other possible
causes
Remove valve and check for
sticking
Remove spring and check the
rate
Check oil viscosity
Refer to EDM
Check wear with
a compara- tor
Insert valve in guide and
check side movement
Remove seals and check for
splits or wear
Measure rings in bore
Check for blue smoke from
exhaust
Check oil viscosity
Wipe clean, run engine and
visually check
Wipe bell housing clean, run
engine and visually inspect
for cleanliness
Visual check
Visual check
Check valve clearances
Remove valves and check
springs
Remove valves and check
guides
Remove valves and check in
- serts
Check oil pressure gauge re
- ading
Check valve timing
Check valve clearances and
for lack
of lubrication
Remove front timing cover
and check for wear
Remedy
Renew the pump
Remove oil pick
-up pipe and
clean strainer
Fit new '0' rings
Fit new '0 rings or clear oil
gallery
Clean or renew the valve
Renew spring
Renew oil and filter
Rectify as required
RefertoToo Cold fault finding
in Section 4.1, VSM
Rebore cylinders as necess
-
ary
Renew valve guides as
necessary
Renew in sets
Renew rings in sets and re
- bore as necessary
Renew head gasket
Renew oil and filter
Renew seal
Renew seal
Renew gasket Renew cylinder block
Adjust valve clearances
Renew as necessary
Renew as necessary
Renew as necessary
Refer to Insufficient Oil Pres
- sure fault finding
Adjust valve timing
Adjust valve clearances.
Refer to Insufficient Oil Pres
- sure fault finding
Renew as
necessaw
0
0
0 ~~~
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AJ16 Engine Service Manual
Symptom
Joisy chains
)etonation knock pinking)
.oss of power
Gugh running at iormal engine speed Possible
Cause
Low oil pressure
Tensioners not released
Chains worn
Sprockets worn
Tensioner worn
Ignition timing too far ad
- vanced
Head gasket leaking
Fuel
/ air mixture too weak
Engine running
too hot
Valve timing incorrect
Incorrect grade fuel
Burned valves Sticking valves
Poor engine tune
Insufficient valve clearance
Fuel injection fault
Lowcompression in cylinders
Ignition fault
Valve timing incorrect
Partial seizure of engine
Worn
camshaftb)
Incorrect grade fuel
Sticking valves Broken valve springs Piston fault
Leaking head gasket
Valve burned out
Valve seat burned out
Ignition fault
Fuel injection fault
Check
Take reading from oil pres- sure gauge when engine is
hot
Remove camshaft cover and
check tension of chain (top
chain). Remove timing cover
to check bottom chain tension
Visually check
/ remove and
check for wear
Visual check
Visual check
Refer to EDM
Check engine oil level and
checkfor contamination of oil
Pressure test cooling system
and check for contamination
of coolant in header tank
Refer to EDM
Check valve timing
If all other checks
OK, this
could be the cause
Check cylinder compressions
Check cylinder compressions
Refer to EDM
Check valve clearance
Check compressions
Refer to EDM
Check valve timing
Remove spark plugs and ro
- tate crankshaft
Remove
camshaft(s) and
check for wear
If all other checks OK this
could be the cause
Check cylinder compressions
Check cylinder compressions
and for bent valve stems
Check cylinder cornpressions
Check cylinder compressions
Check cylinder compressions
Refer to
EDM
Remedy
Refer to Insufficient Oil Pres- sure fault finding
Insert
3 mm Allen key and
turn tensioner anti-clock- wise, compress tensioner to
release bottom chain
Renew as necessary
Renew as necessary
Renew as necessary
Rectify as required
Renew head gasket
Rectify
as required
Refer
to Overheating fault
finding in Section 4.1, VSM
Adjust valve timing
Drain fuel tank and refill with
correct grade fuel
Remove cylinder head and
renew valves
Remove cylinder head and
renew valves
/ guides or
springs
Rectify as required
Adjust as necessary
Refer to Fuel System fault
finding in Section 5.1, VSM
Rebore
1 re-ring as necessary
Rectify as required
Adjust valve timing
Overhaul engine as required
Renew
camshaft(s)
Drain fuel tank and refill with
correct grade fuel
Renew valve, springs or
guides
Renew valve springs and
valves as required
Renew pistons
Refer to Detonation Knock
fault finding
Renew valve
Re
-cut or renew valve seat
Rectify as required
Refer to Fuel System fault
Tindim in Section 5.1, VSM
issue 1 August 1994 5

AJ16 Engine Service Manual
Symptom
3ough running at iormal engine speed
continued)
3ough idle
Engine backfires
Engine spits back
nto
air box
Engine fails to idle
Possible Cause
Air leaking into intake mani- fold
Leaking exhaust
Valve timing incorrect
Incorrect ignition timing
Valve burned out
Ignition fault
Fuel injection fault
Air leakage
intolfrom the ex- haust system
Leakage past valves and
guides
Ignition timing retarded
Incorrect valve timing
Valves not closing properly
Excessively weak mixture
Air leaking into intake mani
- fold
Incorrect ignition timing
Valve clearances insufficient
Cylinder head gasket leaking
Blockage in exhaust system
Check
Run engine and check for
leaks / whistling. Spray 'Easy Start' around suspect area
[the engine speed will in- crease if an air leak is present)
Visual check
Check valve timing
Refer to EDM
Check cylinder compressions
Refer to EDM
Checkfor leaksor blows in the
system
Check for crankcase fumes
and refer to EDM for analysis
of exhaust gases
Refer to EDM
Check valve timing
Check valve clearances
Check for wear or gum in
valve guides
Check for poor seating of
valves
Refer to EDM
Run engine and check for
leaks
/ whistling. Spray 'Easy
Start' around suspect area
(the engine speed will in- crease if an air leak is present)
Refer to EDM
Check clearances
Check for restrictions
Remedy
Renew gasket or manifold
Repair leak or renew exhaust
Adjust valve timing
Rectify as required
Renew valve
Rectify as required
Refer to Fuel System fault
finding in Section
5.1, VSM
Repair leaks or renew system if necessary
Remove the cylinder head
and overhaul
Rectify as required
Adjust valve timing
Adjust valve clearances
Renew guides or decarbonize
the cylinder head
Overhaul the cylinder head
Rectify as required
Renew intake tube
or gasket
Rectify as required
Adjust clearances
Refer to Detonation Knock
fault finding
Remove the restrictions or
renew components as
necessary
Issue 1 August 1994 6