8. Valve Guide Reaming/Valve and Seat Grinding

Valve Guide Reaming/Valve and Seat Grinding

Tools Required
* KM-340-1-C Cutter Set
* KM-571-B Gage or equivalent
* KM-805 Valve Guide Reamer

Valve Grind - In





Caution: Refer to Safety Glasses Caution Safety Glasses Caution.

1. Lubricate the valve seat using a fine-grained paste.
2. Lift the valve rhythmically from the seat with a commercially-available valve grinding tool in order to distribute the paste.




3. Inspect the contact pattern on the valve head and in the cylinder head.
4. Clean the valves, the valve guides, and the cylinder head.

Valve Grind

Caution: Refer to Safety Glasses Caution Safety Glasses Caution.

Important: The valve may be reground only 2 times. Do not grind the valve stem end.





1. Ensure that there are no crater line burns on the valve cone.
2. Ensure that the angle at the valve face is 45 degrees.
3. Inspect the assembly height of the intake valves and the exhaust valves.

Valve Guide - Ream





Caution: Refer to Safety Glasses Caution Safety Glasses Caution.

1. Measures the diameter of the valve guide using the KM-571-B (1) and a commercially available inside micrometer.





Important: Valve oversizes may already have been fitted in production.


2. An oversize service code is on the valve guide and the valve stem end. The Valve Guide Reaming Table gives the correct size, reamer, and production code for each service code. Refer to the Valve Guide Reaming Table in Engine Mechanical Specifications Service Limits & General Specifications for correct size, reamer, production code, and service code for each service.
3. Ream the valve guide with the KM-805 (1) from the upper side of the cylinder head to the next oversize.
4. After reaming, cross out the code and emboss the valve guide with the new code.

Valve Seat - Cut





Caution: Refer to Safety Glasses Caution Safety Glasses Caution.

1. Place the cylinder head on wooden blocks.
2. Cut the intake and the exhaust valve seats using the KM-340-7 as follows.

* Cut the valve seat to a 45 degree surface (b) with the KM-340-13.
* Cut the upper correction angle to a 30 degree surface (a) with the KM-340-13.
* Cut lower correction angle to a 60 degree surface (c) with the KM-340-26.

3. Clean the chippings from the cylinder head.
4. Inspect the dimension for the valve seat width.

* The intake valve seat width is 1.2-1.4 mm (0.47-0055 in).
* The exhaust valve seat width is 1.4-1.8 mm (0.055-0.070 in).

5. Inspect the assembly height of the intake valves and the exhaust valves. If the specified dimension is exceeded, install new valves. Inspect the assembly height of the intake valves and the exhaust valves again. If the valve assembly height is still too large despite replacing the valves, replace the cylinder head.