Valve Guide: Service and Repair

VALVE GUIDE
1) Check the clearance between valve guide and stem. The clearance can be checked by measuring the outside diameter of valve stem and the inside diameter of valve guide with outside and inside micrometers respectively.

Valve guide inner diameter: 6.000 - 6.015 mm (0.2362 - 0.2368 in)





2) If the clearance between valve guide and stem exceeds the specification, replace guide as follows:
(1) Place cylinder head on ST1 with the combustion chamber upward so that valve guides enter the holes in ST1.
(2) Insert ST2 into valve guide and press it down to remove valve guide. ST1 498267200 CYLINDER HEAD TABLE ST2 499767200 VALVE GUIDE REMOVER





(3) Turn cylinder head upside down and place ST as shown in the Figure. ST 499767000 VALVE GUIDE ADJUSTER
(4) Before installing new oversize valve guide, make sure that neither scratches nor damages exist on the inside surface of the valve guide holes in cylinder head.





(5) Put new valve guide, coated with sufficient oil, in cylinder, and insert ST1 into valve guide. Press in until the valve guide upper end is flush with the upper surface of ST2.
ST1 499767200 VALVE GUIDE REMOVER
ST2 499767000 VALVE GUIDE ADJUSTER





(6) Check the valve guide protrusion.

Valve guide protrusion: L 12.0 - 12.4 mm (0.472 - 0.488 in)





(7) Ream the inside of valve guide with SI. Gently rotate the reamer clockwise while pressing it lightly into valve guide, and return it also rotating clockwise. After reaming, clean valve guide to remove chips. ST 499767400 VALVE GUIDE REAMER

CAUTION:
- Apply engine oil to the reamer when reaming.
- If the inner surface of the valve guide is torn, the edge of the reamer should be slightly ground with an oil stone.
- If the inner surface of the valve guide becomes lustrous and the reamer does not chips, use a new reamer or remedy the reamer.

(8) Recheck the contact condition between valve and valve seat after replacing valve guide.