Valve Clearance: Adjustments

CAUTION: DO NOT rotate the engine while the camshaft is disconnected.
DO NOT move tappets from their home bore. Keep in same location unless fitting new ones.

Camshaft Cover:

CHECK
- Remove the camshaft covers.

Fig. 8 Valve adjustment:

LEFT CAMSHAFT
- Rotate the engine as necessary and measure the valve clearances between the heel of the LH camshaft and the cam followers .
- Make a note of each reading. The correct clearance is:
Inlet 0.031-0.036 mm (0.012-014in).
Exhaust 0.031-0.036 mm (0.012-014in).

ADJUST
Should the clearances be incorrect, proceed as follows:
- Remove the rubber grommet from the front of the timing cover.

Timing Chain Tensioner Retracting Tool:

- Insert JD 50 (Release Tool) through the timing cover and release the locking catch on the timing chain tensioner.
- Fit JD 50 (Chain Tension Retainer) and retract the timing chain tensioner until the locking catch is engaged.
- Remove Service Tools JD 50.

Camshaft Timing Gauge:

- Rotate the engine until Timing Gauge C3993 can be inserted into the recess in the LH camshaft. Note the two uppermost camshaft sprocket retaining bolts.
- Remove Timing Gauge C 3993.
- Rotate the engine until the two LOWER camshaft sprocket retaining bolts become accessible. Push back the lock tabs and remove the two retaining bolts.
- Rotate the engine to the camshaft removal position and refit Timing Gauge C 3993. Remove the remaining two camshaft sprocket bolts and fit JD 40 or equivalent.
- Gradually loosen each camshaft cap securing nut two turns at a time until the valve springs are fully relaxed.

L/H Camshaft:

- Note the cap to carrier relationship and remove the nuts and washers and lift off the bearing caps.
- Remove the LH camshaft.
- Remove the cam followers.
- Remove each shim in turn, check the size with a micrometer and note the reading.
- Calculate the size of shim required following the examples given below.

Adjusting Shim Chart:

- There are twenty-six shims available, each identifiable by a letter of the alphabet, starting at 0.085in (A), increasing in O.001in stages to 0.110in (Z). When the correct shim sizes have been obtained, refit shims and cam followers to the cam carrier.
- Lubricate the camshaft journals with clean engine oil.
- Refit the camshaft to the camshaft carrier, using C 3993 to position the camshaft correctly.
- Fit the bearing caps, washers and securing nuts. Progressively tighten the securing nuts to the correct torque, working from the center outwards.
- Recheck the valve clearances. Repeat the adjustment procedure if necessary.
- Check that Timing Gauge C 3993 is in position. Engage the camshaft sprocket to the camshaft, fit and tighten one retaining bolt
- Remove JD 40.
- Remove C 3993.
- Rotate the engine and fit the remaining sprocket retaining bolts. Lock over the tabs.

RIGHT CAMSHAFT
- Repeat the valve clearance adjustment procedure for the RH camshaft.

REFIT
- Fit JD 50 (Chain Tension Retainer) and raise the timing chain tensioner slightly.
- Insert JD 50 (Release Tool) through the timing cover.
- Release the locking catch and allow the tensioner to expand.
- Remove both Service Tools. Refit the rubber grommet to the front of the timing cover.
- Refit the camshaft covers using a new gasket and half moon seal. Apply sealant to the radial edge of a new half moon seal. Fit the seal to the cam carrier.
- Fit and tighten the securing bolts and nuts.
- Refit the cam covers. Refer to CAMSHAFT COVER.
- Evacuate and charge the air conditioning system.
- Refit the air cleaner.
- Reconnect the battery.

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

TORQUE
Bearing caps to carrier 71-13.5 Nm
Camshaft sprocket to camshaft 23-27 Nm
Camshaft cover 11 Nm
EGR valve to throttle housing 9.5-12 Nm
Elbow to inlet manifold 12.2 Nm Hose clips 2.5 Nm
Inlet manifold to cylinder head (nuts) 23-27 Nm
Inlet manifold to cylinder head (bolts) 23-27 Nm
Silencer to compressor union 34 Nm