- Ream the valve guides for oversize valves if the clearance exceeds the
specifications.
- Ream the valve guide bores for the oversize valves as necessary.
- Reconditioning the valve seats is very important.
Recondition valve seat after reaming the valve guide bores.
| • | The valves must seat perfectly for the engine to deliver optimum
power and performance. |
| • | Cooling the valve heads is another important factor. Good contact
between each valve and its seat in the cylinder head is necessary to ensure
that the heat in the valve head is properly carried away. |
| • | Regardless of what type of equipment is used, it is essential
that the valve guide bores are free from carbon or dirt to ensure the proper
centering of the pilot in the guide. |
| • | The valve seats should be concentric to within 0.05 mm (0.031 in)
total indicator reading. |
| • | Reface pitted valves on a valve refacing machine in order to ensure
the correct relationship between the head and the stem. |
| • | Replace the valve if the stem is warped, or if the stem shows signs
of excessive wear. |
| • | Replace the valve if the edge of the head is less than 0.79 mm
(0.031 in) thick after grinding. |
| • | Several different types of equipment are available for reconditioning
valves and valve seats. Use the manufacturers recommendations of equipment
to attain the proper results. |
