Valve tips can be reconditioned by grinding.

Valve tips can be reconditioned by grinding.

• A. False
• B. It can be done but not recommended
• C. Only by polishing
• D. True

Answer: (D)

The concept here is that the contact surface at the valve tip can wear or become damaged, and restoring a true, flat contact surface is sometimes needed for proper rocker-arm contact and valve clearance. Valve tips are ground to clean up burrs and to reestablish a square, flat contact area so the rocker arm can ride evenly and the lash can be set correctly. This is acceptable practice within clear limits. If you grind the tip, you must not remove more material than the manufacturer allows, because taking off too much changes the valve length and alters valve lash and timing. After grinding, you must recheck the valve stem height and the valve lash to ensure everything stays within specifications. If the tip has been ground too much or is excessively worn, the valve should be replaced rather than further ground. So, valve tips can be reconditioned by grinding when done within the specified limits and followed by proper measurement and rechecking of clearances.

The concept here is that the contact surface at the valve tip can wear or become damaged, and restoring a true, flat contact surface is sometimes needed for proper rocker-arm contact and valve clearance. Valve tips are ground to clean up burrs and to reestablish a square, flat contact area so the rocker arm can ride evenly and the lash can be set correctly.

This is acceptable practice within clear limits. If you grind the tip, you must not remove more material than the manufacturer allows, because taking off too much changes the valve length and alters valve lash and timing. After grinding, you must recheck the valve stem height and the valve lash to ensure everything stays within specifications. If the tip has been ground too much or is excessively worn, the valve should be replaced rather than further ground.

So, valve tips can be reconditioned by grinding when done within the specified limits and followed by proper measurement and rechecking of clearances.