Engine - Valve Guide Cleaning
No: 12/01/00/NASRef:
Issue: 1
Date: 09/29/00
Use of Land Rover Tools for Valve Guide Cleaning
AFFECTED VEHICLE RANGE:
Range Rover (LH & LP) All
Discovery (LJ & LT) All
Defender (LD) All
SITUATION:
CYLINDER HEAD OVERHAUL DIFFICULTIES
Cylinder head overhauls, particularly in cases of exhaust valve sticking, have previously been carried out using a single Valve Guide Cleaner (LRA-12-003) as directed in the Land Rover V8 Engine Overhaul Manual. The use of the single cleaner has in some cases been difficult. Also repeat valve stick failures due to further carbon build-up over time have occurred.
RESOLUTION:
STEPPED SET OF VALVE GUIDE CLEANER TOOLS
Land Rover has now introduced a stepped set of three cleaners, designed to increase the exhaust valve guide internal diameter by 10 microns (0.0004"), and to ensure that all carbon and valve guide material can be removed as easily as possible.
The process set out in this TIB should always be used where exhaust valve stick is suspected or confirmed to have occurred. This process replaces the exhaust valve guide process described in the Engine Overhaul Manual and should be used for all valve replacement and cylinder head overhaul processes.
TOOL INFORMATION
WARRANTY CLAIMS
Normal warranty policy and procedures apply.
REPAIR PROCEDURE
NOTE:
Vehicles with Bosch Engine Management systems require Prior Authorization before performing valve stick repairs.
1. Confirm exhaust valve stick occurrence by identifying appropriate misfire codes via TestBook.
2. Remove rocker shaft and valve springs.
3. Verify sticking exhaust valve diagnosis before head removal by manually moving the valves.
4. Refer to the Land Rover Engine Overhaul Manual on latest RAVE CD and remove cylinder heads.
5. Remove inlet and exhaust valves.
CAUTION:
The Valve Guide Cleaners are hand tools only, and MUST NOT be used with any power tool. Use of power tools will lead to premature wear of the tool and damage to the valve guide.
CAUTION:
The process outlined in Steps 6 through 8 should be used to clean exhaust valve guides only. Perform intake valve guide cleaning as described in Step 9.
NOTE:
Cleaner LRA-12-008 is designed to match the nominal size of the valve guide. It is possible that a small amount of valve guide material will be removed from valve guides that are manufactured at the lower end of the tolerance band.
6. Insert cleaner LRA-12-008 by hand into each exhaust valve guide from the combustion face side of the cylinder head using T-handle LRA-12-005.
^ Turn cleaner carefully clockwise to clear out all carbon deposits from the guide.
^ Continue turning until the cleaner can be withdrawn from the other end of the guide to prevent burrs being formed on the inner diameter of the guide.
^ Clear out all loose material from the valve guides using the valve guide brush LRA-12-004.
^ Ensure that no carbon deposits or valve guide material remain inside the guides.
NOTE:
Cleaner LRA-12-003 is designed to enlarge the valve guide to the top of the tolerance band. A small amount of valve guide material is likely to be removed during this process.
7. Insert cleaner LRA-12-003 by hand from the combustion face side of the cylinder head using T-handle LRA-12-005.
^ Turn cleaner carefully clockwise.
^ Continue turning until the cleaner can be withdrawn from the other end of the guide.
^ Clear out all loose material from the valve guides using the valve guide brush LRA-12-004.
^ Ensure that no deposits or valve guide material remain inside the guides.
NOTE:
Cleaner LRA-12-007 is designed to enlarge the valve guide to 10 microns (0.0004") oversize. A small amount of valve guide material will be removed during this process.
8. Insert cleaner LRA-12-007 by hand from the combustion face side of the cylinder head using T-handle LRA-12-005.
^ Turn cleaner carefully clockwise.
^ Continue turning until the cleaner can be withdrawn from the other end of the guide.
^ Clear out all loose material from the valve guides using the valve guide brush LRA-12-004.
^ Ensure that no valve guide material remains inside the guides.
9. If carbon deposits are present in the inlet valve guides, insert cleaner LRA-12-003 by hand into each valve guide using T-handle LRA-12-005.
^ Turn cleaner carefully clockwise to clear out all carbon deposits from the guide.
^ Continue turning until the cleaner can be withdrawn from the other end of the guide.
^ Clear out all loose material from the valve guides using the valve guide brush LRA-12-004.
^ Ensure that no carbon deposits or valve guide material remain inside the guides.
10. Clean all carbon deposits from both inlet and exhaust valves, including the valve stems.
NOTE:
Exhaust valves should only be replaced with new items if the existing exhaust valves are not of the "carbon-break" type or the valve is damaged. Carbon-break valves are easily identified by the reduced diameter section on the valve stem just above the valve head (Figure 1). Valve replacement is unnecessary in most cases.
11. Lap-in all valves using a suitable valve grinding compound.
12. Remove all traces of grinding compound.
13. Assemble cylinder head using new valve stem seals on all valves.
14. Refer to the Land Rover Engine Overhaul Manual and install the cylinder heads.
15. Start the engine and check for any leaks.
16. Clear any codes stored in the engine ECU, and perform drive cycle C.
17. Check for any newly stored codes using TestBook.
18. If new codes are stored, follow appropriate diagnostic procedures.