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Home >> Jaguar >> 1992 >> XJ-6 L6-4.0L >> Repair and Diagnosis >> Engine, Cooling and Exhaust >> Engine >> Camshaft, Lifters and Push Rods >> Camshaft >> Service and Repair

Camshaft: Service and Repair


Remove
- Remove the distributor cap and leads assembly.
- Disconnect the cam cover breather hose.

Camshaft Cover:





- Remove the camcover to cylinder head securing screws (1).
- Remove the camcover (2).
- Remove and discard the camcover gasket (3), and half moon seals (4).

Camshaft Timing Gauge:





- Rotate the engine and set number 1 cylinder at TDC using Service Tool 18G 1433.
- Remove the distributor and block off the aperture to prevent ingress of dirt and dust.

Sprocket Bolts:





- Push back the lock tabs (1) from the camshaft sprocket securing bolts (2).
- Loosen the bolts and tab washers.

Fig. 14 Upper Timing Chain Tensioner Removal:





- Remove the upper chain tensioner valve clamp bolt (1), remove the clamp (2), and remove the valve (3).
- Using a 3mm Allen key, wind back the tensioner (turn clockwise) until the snail engages in the park position.
- Remove the tensioner housing securing bolt (4).

Tensioner:





- Withdraw the tensioner assembly (2,3).
- Remove and discard the O-ring (1) and gasket.
- Remove the camshaft sprocket securing bolts/tab washers and remove the sprockets.

Fig. 15 Cylinder Head Bolt Spacer Locations:





- Remove the cylinder head bolt from No 2 cap, LH camshaft (1).
- Remove the cap securing bolts from No 2 cap, LH camshaft.
- Remove No 2 cap from the LH camshaft.
- Fit spacer tool 18G 1435 (2) to the head. Fit and torque tighten the cylinder head bolt.
- Repeat the procedure for Nos 3, 4, 5 and 6 caps, LH camshaft (3).
- Remove the cylinder head bolt from No 7 cap, LH camshaft.
- Remove alternately the securing bolts from Nos 1 and 7 caps, until the LH camshaft is free. Lift the camshaft from the cylinder head, and fit spacer tool 18G 1435 to No 7 cylinder head bolt position (5). Fit and torque tighten the bolt.
- Repeat the procedure for the RH camshaft.
- Clean all components and examine for wear and damage. Replace all worn or damaged components.
- Lubricate the new LH camshaft.
- Fit the camshaft at approximately TDC.
- Lubricate Nos 1 and 7 caps.
- Fit No 1 cap. Fit but do not tighten the cap securing bolts.
- Remove No 7 cap cylinder head bolt.
- Remove the spacer tool.
- Fit No 7 cap. Fit but do not tighten the cap securing bolts.
- Finally tighten Nos 1 and 7 cap securing bolts in sequence.
- Remove No 4 cap cylinder head bolt and remove the spacer tool.
- Lubricate and fit No 4 cap.
- Fit and tighten No 4 cap securing bolts.
- Fit and tighten No 4 cap cylinder head bolt.
- Repeat the procedure for Nos 2, 3, 5 and 6 caps, LH camshaft.
- Set the LH camshaft to TDC.
- Repeat the procedure for the RH camshaft.
- Rotate the engine as necessary to measure the valve clearances between the heel of the camshaft and the cam followers.
- The correct clearance is 0.012 to 0.014 in.
- Make note of each clearance measurement.
- Should the clearances be incorrect, proceed as follows: Rotate the engine and set number 1 cylinder at TDC using Service Tool 18G 1433.
- Remove the cylinder head bolt from No 2 cap, LH camshaft (1).
- Remove the cap securing bolts from No 2 cap, LH camshaft.
- Remove No 2 cap from the LH camshaft.
- Fit spacer tool 18G 1435 (2) to the head. Fit and torque tighten the cylinder head bolt.
- Repeat the procedure for Nos 3, 4, 5 and 6 caps, LH camshaft (3).
- Remove the cylinder head bolt from No 7 cap, LH camshaft.
- Remove alternately the securing bolts from Nos 1 and 7 caps, until the LH camshaft is free.
- Lift the camshaft from the cylinder head, and fit spacer tool 18G 1435 to No 7 cylinder head bolt position (5). Fit and torque tighten the bolt.
- Repeat the procedure for the RH camshaft.

Valve Clearance Calculation
- Remove all the shims, or only those requiring adjustment, check the size of the existing shims with a micrometer and note the reading.
- Calculate the size of the shim required following the examples below.

VALVE CLEARANCES
Inlet and Exhaust 0.012-0.014in

EXCESSIVE CLEARANCE - EXAMPLE
Size of existing shim 0.100
Plus the actual clearance noted 0.019
= 0.119
Less the specified valve clearance 0.013

Equals required shim size 0.106

INSUFFICIENT CLEARANCE - EXAMPLE
Size of existing shim 0.107
Plus the actual clearance noted 0.010
= 0.117
Less the specified valve clearance 0.013

Equals required shim size 0.104

Letter Thickness

A 0.085 in
B 0.086 in
C 0.087 in
D 0.088 in
F 0.089 in
G 0.089 in
H 0.090 in
I 0.091 in
J 0.094 in
K 0.095 in
L 0.096 in
M 0.097 in
N 0.098 in
0 0.099 in
P 0.100 in
0 0.101 in
R 0.102 in
S 0.103 in
T 0.104 in
U 0.105 in
V 0.106 in
W 0.107 in
X 0.108 in

Refit
- Fit the relevant shims to the cylinder head.
- Fit the LH camshaft at approximately TDC.
- Lubricate Nos 1 and 7 caps.
- Fit No 1 cap. Fit but do not tighten the cap securing bolts.
- Remove No 7 cap cylinder head bolt.
- Remove the spacer tool.
- Fit No 7 cap. Fit but do not tighten the cap securing bolts.
- Finally tighten Nos 1 and 7 cap securing bolts in sequence.
- Remove No 4 cap cylinder head bolt and remove the spacer tool.
- Lubricate and fit No 4 cap.
- Fit and tighten No 4 cap securing bolts.
- Fit and tighten No 4 cap cylinder head bolt.
- Repeat the procedure for Nos 2, 3, 5 and 6 caps, LH camshaft.
- Set the LH camshaft to TDC.
- Repeat the procedure for the RH camshaft.
- Fit and align the camshaft sprockets to the chain and the camshafts.
- Move all the slack to the tensioner side.

Timing Chain Tensioner Tool:





- Fit upper chain tensioner tool 18G 1436. Fit and tighten the bolts.
- Tension the cam chain.

Camshaft Sprocket:





- Remove the inner sprocket spring clip (1).
- Remove the inner sprocket (2) from the outer sprocket (3) and align the securing bolt holes.
- Fit the tab washers. Fit and tighten the securing bolts.
- Lock over the tabs.
- Refit the inner sprocket securing clip.
- Repeat the procedure for the other sprocket.
- Loosen the chain tensioner tool bolts.
- Remove the tensioner tool.
- Clean the tensioner assembly and gasket faces.
- Fit a new housing gasket. Fit a new O-ring. Lubricate the O-ring.
- Fit the tensioner assembly to the cylinder head.
- Fit and tighten the tensioner securing bolt.
- Fit but do not tighten the valve clamp bolt.
- Clean the valve assembly and fit new O-rings.
- Lubricate the tensioner valve.
- Using an Allen key, release the tensioner, ie turn the, Allen key anti-clockwise.
- Fit the tensioner valve. Position the clamp over the valve. Tighten the clamp bolt.
- Refit the camcover using a new gasket and half moon seals.
- Refit the distributor, cap and leads.
- Reconnect the breather hose.

TORQUE FIGURES
Camshaft sprocket to camshaft 23-27 Nm
Cylinder head bolts
Tighten to 52-54 Nm
Rotate the bolts clockwise through 90 degrees
Distributor clamp plate to timing cover 9.5- 12 Nm
Upper chain tensioner to cylinder block 23-27 Nm













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