Valve Guide Reaming/Valve and Seat Grinding

VALVE GUIDE REAMING PROCEDURE
Perform the following steps for reaming the valve guide:
1. Clean the valve guide thoroughly.

2. Insert the J 42096 reamer into the valve guide from the top of the cylinder head.
3. Apply light hand pressure while turning the reamer until the reamer is all the way through the valve guide.
4. Remove the J 42096.
5. Clean the valve guide of all metal shavings.
6. Clean the cylinder combustion chamber of all metal shavings.

VALVE AND VALVE SEAT GRINDING PROCEDURE
- TOOLS REQUIRED
- J 41775 Valve Seal Installer
- J 8062 Valve Spring Compressor

Seating of valves must be perfect for engine assembly to deliver optimum power and to deliver optimum performance. Another important factor is the cooling of the valve heads. Good contact between each valve and its seat in the cylinder head is necessary to insure that heat in the valve head will be properly carried away.

Several different types of equipment are available for reconditioning valve seats. Carefully follow the equipment manufacturer recommendations to attain proper results. Regardless of what type of equipment is used, it is essential that valve guide bores be free from carbon and/or free from dirt to ensure proper centering of the pilot in the guide.

Valves that are slightly pitted can be refaced to proper angle, insuring correct relation between head and stem, on a valve refacing mechanism. Replace valve stems which show excessive wear. Replace valves that are warped excessively. Replace the valve if the edge of the valve head is less than 1.6 mm (0.0625 in) thick after grinding.

Use a 30 degree and a 60 degree stone to control valve seat width.

Grind the valves at a 90 degree 40 minute angle. Grind the valve seat at a 90 degree angle. The 40 minute difference in angles provides better sealing. The valve seat width should be:
- The intake valve seat width should be 1.0 - 1.4 mm (0.039 - 0.055 in).
- The exhaust valve seat width should be 1.4 - 1.8 mm (0.055 - 0.070 in).