XJ-6 L6-4.2L (1983)
Valve Clearance: Adjustments
Service tool: Valve timing gauge C 3993
NOTE: If checking valve clearances with the cylinder head removed from the engine, the camshafts must be fitted and checked one at a time. If one
camshaft is rotated while the other is in position, fouling is likely between inlet and exhaust valves.
If necessary, remove the camshaft covers.
Figure 15
1. Rotate the camshafts and record the clearance between the back of each cam in turn, and the respective tappet, using a feeler gauge as shown (1,
Fig 15). If adjustment is necessary, proceed with operations below as appropriate.
Figure 16
2. If the cylinder head is on the engine, before removing the last securing bolt, rotate the engine until the valve timing gauge C 3993 can be located in
the front flange of each camshaft (1, Fig 16). If necessary, disconnect the sprockets from the camshafts.
NOTE: Do not rotate the engine while the camshaft sprockets are disconnected.
3. When the cylinder head is on the engine and the camshaft sprockets disconnected, ensure that no piston is at TDC otherwise valve/piston fouling
could occur.
4. Remove the camshaft bearing caps (2, Fig 16) and lift the camshaft clear.
5. Remove each tappet, taking careful note of its location.
6. Remove and check the adjusting pad.
NOTE: Subtract the appropriate valve clearance from the dimension obtained above and select suitable adjusting pads which equal this new
dimension.
7. Adjusting pads are available rising in 0.03 mm (0.001 in) sizes from 2.16-2.79mm (0.085-0.110 in) and are etched on the surface with a letter 'A'
to 'Z', each letter indicating an increase in size of 0.03 mm (0.001 in).
8. Fit selected adjusting pads and fit the tappets.
9. Fit the camshaft bearing caps and nuts.
NOTE: If the cylinder head is on the engine, locate the camshaft using gauge C 3993 before tightening the bearing cap nuts.
10. Tighten the bearing cap nuts to the correct torque.
11. Connect the camshaft sprockets.
12. Refit the camshaft covers.
