Valve Clearance: Service and Repair

Valve Clearances - Check and Adjust

Removal
1. Open the engine compartment and fit paintwork protection sheets. Open to the service position.
2. Carefully remove both engine covers, taking care not to damage the plastic fixings or the rubber inserts.
3. Open the driver's door, or both doors if necessary, to allow the side glass to drop. Ensure that the doors remain open until after the battery has been disconnected.





4. Disconnect the battery ground cable.
Remove the battery cover.
5. Remove the cam cover from Bank 1 and Bank 2; including the purge valve, the on-plug ignition coils and the air intake tube/air flow meter/air cleaner cover assembly.
6. Check, and note the valve clearances, as described earlier in this section.
7. Use a rag to wipe up as much oil as possible from the tappet wells.
8. Valve adjustment involves considerable repetition. A SUMMARY OF THE PROCEDURE follows:
Install the adjusting tool base plate to one cylinder head.
Rotate the crankshaft to position four valves ready for adjustment.
Use the attachment part of the special tool to adjust two valve clearances. Transfer the attachment and adjust the other two valve clearances.
Remove the attachment part from the adjusting tool base plate.
Repeat steps 2 to 4 three more times until all sixteen valves on the first cylinder head have been adjusted.
Repeat steps 1 to 5 for the other cylinder head.
Remove all equipment and reassemble the engine.
9. The following instructions describe the PROCEDURE FOR ADJUSTING THE VALVE CLEARANCES.





10. Install the base plate of the tappet adjusting tool 303-540 to one of the heads; use the bolts which are supplied with the tool.
It should be installed along the head, between the two camshafts, and bolted to the tapped holes which normally secure the cam cover.
11. Rotate the crankshaft so that there are four valves which are 'off the cam'(cam lobes uppermost), so that their clearance may be measured.





12. CAUTION: Do not rotate the crankshaft while the attachment is installed to the base plate.

Install the attachment of 303-540 to the base plate.
Set the fingers of the attachment to the highest position (unscrew the knurled bolts).
Install the attachment to the base plate, adjacent to the first two valves to be adjusted.
Tighten the screws to secure the attachment to the base plate.





13. Position the fingers on to the outer edges of the tappet. It is essential that the recessed step on each finger, locates on the edge of the tappet as indicated. The use of a mirror will help, as viewing access is restricted.





14. Tighten the knurled bolts to compress the valve springs, until a firm resistance is felt.





15. WARNING: THE FOLLOWING OPERATIONS REQUIRE THE USE OF COMPRESSED AIR - ALWAYS WEAR SUITABLE EYE PROTECTION.

Remove, clean and measure the shims.
Surround the immediate working area with clean rag to contain any loose objects and shims displaced by the compressed air.
Use 303-590 Air Gun (with a fan nozzle) aimed at the edge of the shim to lift it from the tappet.
Remove the shim from each tappet, noting the position of each.
16. Clean and measure the thickness of each shim.
17. Assess the increase or decrease required in shim thickness to produce the correct valve clearance.
18. Select two shims of the correct size, lubricate each and install each to the respective tappet (as calculated in the previous step). Shims must be installed with the size marking facing the tappet NOT the cam.





19. Loosen the knurled screws on 303-540 attachment to allow the valve springs to return to their normal position.
20. Check the valve clearance of the two valves. If the clearance is correct, remove the attachment from the base plate. Transfer the attachment to the other two valves which are In position to be adjusted.
21. Repeat the adjustment procedure, as described in the Summary.

Installation
1. Install the cam covers and associated components.
2. Install the engine covers.
3. Check the engine oil level; rectify as necessary.
4. Move the engine compartment cover from the service position and connect the gas struts.
5. Remove the paint protection sheets and close the cover.
6. Connect the battery and install the battery cover.