Valve Guide: Testing and Inspection
WOBBLE METHODMeasure the guide-to-stem clearance with a dial indicator while rocking the stem in the direction of normal thrust (wobble method).
- Intake Valve Stem-to-Guide Clearance:
Standard (New): 0.04-0.09 mm (0.002-0.004 inch)
Service Limit: 0.16 mm (0.006 inch)
- Exhaust Valve Stem-to-Guide Clearance:
Standard (New): 0.11-0.16 mm (0.004-0.006 inch)
Service Limit: 0.24 mm (0.009 inch)
- 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 still exceeds the limit, recheck it using the alternate method below, then replace the valve and guide, if necessary.
BALL GAUGE METHOD
An alternate method of checking guide to stem clearance is to subtract the Outer Diameter (O.D.) of the valve stem, measured with a micrometer, from the Inside Diameter (I.D.) of the valve guide, measured with an inside micrometer or ball gauge.
1. Take the measurements in three places along the valve stem and three places inside the valve guide.
- Intake Valve Stem-to-Guide Clearance:
Standard (New): 0.020-0.045 mm (0.0008-0.0018 inch)
Service Limit: 0.08 mm (0.003 inch)
- Exhaust Valve Stem-to-Guide Clearance:
Standard (New): 0.055-0.080 mm (0.0022-0.0031 inch)
Service Limit: 0.12 mm (0.005 inch)
2. The difference between the largest guide measurement and the smallest stem measurement should not exceed the service limit.