1994 JAGUAR XJ remove seats

AJ16 Engine Service Manual
4.5 Cylinder Head, Overhaul
SRO 12.29.19
1 Remove the cylinder head, see Section 4.4.
1 Place the cylinder head on suitable blocks on a bench.
1 Remove the spark plugs and the intake and exhaust mani-
folds.
1 Mark the position of the camshaft caps relative to the
head, remove the cap securing bolts and remove the caps
(1 Fig. 1).
1 Remove the camshafts.
. Using a magnet, lift out the cam followers (1 Fig. 2).
1 Remove the valve springs, using Service Tool MS 1519A,
1 Retrieve the collars, collets and spring retaining plates.
1 Remove the valves, noting the relationship between valve
and guide to ensure correct pairing during re-assembly.
* Remove the seals from the intake valve guides and re- move the cylinder head rear blanking plate.
1 Clean all component parts.
1 Check for wear and burning of valves or seats.
1 Check the cylinder head face for distortion.
1 If distortion is evident, a maximum of 0,25 mm may be re- moved by skimming the cylinder head.
1 Taking care not to damage the inside surface of the com-
bustion chambers, clean the intake and exhaust ports.
CAUTION: When using scrapers or wire brushes for re- moving carbon deposits, avoid scratching the
valve faces and seats. A soft wire brush is the most suitable implement for this purpose.
1 Clean all carbon and other deposits from the valve guide
using a suitable valve guide brush. Thoroughly wash the
cylinder head to ensure that all loose carbon is removed
and dry the cylinder head with a high pressure air line.
. After cleaning and polishing each valve, examine the
stems for straightness and wear, using a suitable dial
gauge and vee
-block see example at Fig. 3.
1 Examine the valve faces for burns, pitting and distortion.
Renew any valves that are excessively worn, bent, or too
badly pitted to be salvaged by refacing.
Support the
valves using a wooden block.
valve spring compressor.
/ 112 310
Fig. 1
Fia. 2
I
JlZ 268
Fia. 3 I " 1
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AJ16 Engine Service Manual
Note: No attempt should be made to clean up a burnt or
badly pitted valve face by extensive 'grinding in' of
the valve to the seat.
m Lightly lap the valves into the seats with a fine grinding
compound. The reseating operation should leave the fin- ished surfaces smooth. Excessive lapping will groove the
valve face resulting in a poor seat when the engine is hot.
A
- Correctly seated B - Undesirable condition C - Rectified condition
. Totestthe valvesforconcentricity withtheirseats,coatthe face of the valve with Prussian blue or similar, and rotate
the valve against the seat. If the valve face is concentric
with the valve stem, a mark will be made all around the
face. Should
a mark be made on only one side of the face,
the face is not concentric with the valve stem. Clean the
valve and again coat with Prussian blue and rotate the
valve against the seat.
. Check that the valve guide is concentric with the valve
seat,
if not, the seat must be re-cut. Whenever valves are
renewed the seats must be re-cut prior to lapping of the
valves. Check valve guide wear by inserting a new valve
into the guide to be checked,
lift it 6 mm from its seat and
rock it sideways.
. Movement of the valve across its seat (A Fig. 2) must not
exceed 0,04 to 0,07 mm. Should the movement exceed
this tolerance, the valve guide must be renewed. Ensure
that the relevant valve guide is selected prior to fitting.
. When new guides are to be fitted they should always be
one size larger than the old guide.
. Cylinder head bores will require reaming as follows: Re- move the old valve guide and ream the cylinder head to
the relevant dimension. Immerse the cylinder head in
boiling waterfor30 minutes. Coat the guide with graphite
grease, and drive in the guide from thecamshaft side until
the snap
-ring is seated in the groove.
b: The interference should not be sufficient to require
the use of excessive force when fitting the guide.
1 After fitting a valve guide, the valve seat must be recut using Service Tool MS 204 (Fig. 3). Examine the valveseat
inserts for pitting or excess wear. If renewal is necessary,
proceed as follows.
1 Remove the inserts by machining, leaving approximately 0,25 mm of metal which can easily be removed by hand
without damaging the cylinder head. Measure the diam- eter of the insert recess in the cylinder head. Grind down
the outside diameter of the new insert to a dimension 0,08
mm larger than the insert recess.
Heat the cylinder head for 30 minutes from cold to a tem- perature of 15OOC 1, Fit the insert ensuring that it beds
evenly in the recess. When the cylinder head has cooled,
re
-cut the valve seat using Service Tool MS 204. For cor- rect valve seat angles see Service Data in the Preliminary
Pages.
If new valve inserts have been fitted, the clearance
between valve stem and cam must be checked, see
Service Data in the Preliminary Pages.
. Fig. 1 shows:
U:
I
A
JIZ 2M
Fia. 2
Fig. 3
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AJ16 Engine Service Manual
. The dimension must be taken between the valve stem and
the back of the cam. Should
this dimension not be ob-
tained, metal must be ground from thevalveseat of the in-
sert.
&&: Use only suitable grinding equipment.
* Remove only very small amounts of metal from the valve
seat at one time before re-checking the clearance.
. Examinethecamfollowersforwear on the topface. Check
for any sign of barreling on the side faces (Fig. 1). Renew
all followers that are worn or suspect. Wash the valves,
springs, collets, followers and air dry.
. After the valve springs have been thoroughly washed,
they must be examined for fatigue and distortion. Renew
as necessary.
. Test the valve springs either by comparison with the fig- ures given in Service Data in the Preliminary Pages, or by
comparison with a new valve spring (using a recom- mended valve spring testing machine).
. To test against a new valve spring, insert both valve
springs end to end between the test equipment. Apply a
load to partly compress the springs and measure their
comparative lengths (Fig.
2).
&@:
. If the distance 'A' is smaller than the distance 'B', then 'A'
b: Spring distortion is determined by positioning the
spring upright on a surface plate and checking the
squareness of each end with a set square (Fig.
3). All
valve springs which have diminished in length and/ or are not square must be renewed.
. Fit the valves into the guides and place the cylinder head
on wooden blocks.
. Fit the valve spring seats, intake valve guide oil seals,
springs and collars.
. Compress the springs using Service Tool MS 1519A and
insert the split collets.
. Refit the original shims (1 Fig. 4) in the valve collar re- cesses. (Ensure that the shims are seated correctly and fit
the cam followers, see Section 4.3).
If the cylinder head has been overhauled to the ex-
tent of having the valve seats recut, each shim
should be 0,010 in. smaller than the original.
. Lubricatethecamshaftsand fittothecylinder head,ensur- ingthattheyarefittedwiththeslotsto thetop. Fitthecam- shaft caps and torque tighten the securing bolts. Measure
the valve clearance between the heel of the cam and the
cam follower, turning the camshaft as necessary to
measure
all the clearances see Section 4.3.
It is advisable to set the valve clearances to the
upper
limit to allow for the clamping effect exper- ienced through torque tightening upon engine re- assembly.
Afinal checkof the valve clearances should be done
when the cylinder head is fitted and torque tigh
- tened to the cylinder block.
Clean the cylinder head thoroughly and checkthe cylinder
head and cylinder block for warping, bowing or cracks.
. Fit the cylinder head, see Section 4.4.
'A' is the old spring.
must be renewed.
&&:
m:
&@:
Fig. 1
K
Fig. 2
I Fig. 4
Issue 1 August 1994 18

0 4.6 Cylinder Head Casting, Renew
SRO 12.29.15
1 Remove the cylinder head, see Section 4.4.
1 Place the cylinder head on suitable blocks on a bench.
1 Remove the spark plugs.
1 Remove the intake valve camshaft cap securing bolts.
1 Remove the camshaft caps.
1 Remove the camshaft.
1 Repeat the procedure for the exhaust camshaft.
1 Remove the cam followers and shims, noting the posi-
1 Remove the valves using Service Tool MS 1519A valve
1 Remove the seals from the intake valve guides.
1 Remove the rear blanking plate.
1 Clean all components and examine for wear and damage.
Renew any worn or damaged parts as necessary.
1 Clean thoroughly the new cylinder head casting.
1 Refit the rear blanking plate to the new cylinder head.
0 1 Smearfinegrindingcompound on tothe face ofonevalve.
1 Oil the valve stem.
1 Fit the valve to the head.
1 Lightly lap the valves into the seats, leaving a smooth fin-
ish to both surfaces.
Note: Excessive lapping will groove the valve face, result- ing in poor seating when hot.
1 Clean the valve and seat.
1 Repeat the procedure for the remaining valves.
1 Fit a new seal to the intake valve guide.
1 Lubricate the valve stem. Fit the valve to the guide. Fit the
. Fit Service Tool MS 1519A spring compressor to the valve.
1 Compress the valve spring, fit and seat the collets, and re- lease the clamp.
1 Repeat the procedure for the remaining valves.
. Refit the shims.
1 Ensure that the shims are seated correctly.
1 Lubricate and fit the cam followers (Fig. 1).
. Lubricate the camshafts and bearings.
1 Fit the camshafts.
1 Fit the camshaft caps.
1 Fit and torque tighten the camshaft cap securing bolts.
. Measure the valve clearance between the heel of the cam
and the cam follower (Fig.
21, turning the camshaft as
necessary to measure all the clearances, see Section 4.3.
Afinal check of the valveclearancesshould be done
when the cylinder head is fitted and torque tigh- tened to the cylinder block.
1 Clean the cylinder head thoroughly and check the cylinder
head and cylinder block for warping, bowing or cracks.
Renew if necessary.
tions
for re
-assembly.
spring compressor.
spring seat, spring and collar.
Note:
1 Fit a new cylinder head gasket.
1 Fit the cylinder head assembly, see Section 4.4.
I II
Fig. 1
JI1 U4
Fig. 2
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