Valve Guide: Testing and Inspection

Valve Stem-to-Guide Clearance Inspection

1. Remove the valves. Valve, Spring, and Valve Seal Removal

2. Slide the valve out of its guide about 10 mm (3/8 in.), then measure the valve stem-to-guide clearance with a dial indicator while rocking the stem in the direction of normal thrust (wobble method).
- If the measurement exceeds the service limit, recheck it using a new valve.

- If the measurement is now within the service limit, reassemble using a new valve.

- If the measurement with a new valve still exceeds the service limit, go to step 3.









3. Subtract the O.D. of the valve stem, measured with a micrometer, from the I.D. of the valve guide, measured with an inside micrometer or ball gauge.
Take the measurements in three places along the valve stem and three places inside the valve guide.

The difference between the largest guide measurement and the smallest stem measurement should not exceed the service limit.