Ford Ranger Maintaince And Repair Manual page 471

HOW TO USE THIS BOOK
Use a micrometer to check the valve stem diameter
Springs, Retainers and Valve Locks
The first thing to check is the most obvious, broken springs. Next check the free length and squareness of each
spring. If applicable, insure to distinguish between intake and exhaust springs. Use a ruler and/or carpenter's
square to measure the length. A carpenter's square should be used to check the springs for squareness. If a
spring pressure test gauge is available, check each springs rating and compare to the specifications chart.
Check the readings against the specifications given. Any springs that fail these inspections should be replaced.
The spring retainers rarely need replacing, however they should still be checked as a precaution. Inspect the
spring mating surface and the valve lock retention area for any signs of excessive wear. Also check for any
signs of cracking. Replace any retainers that are questionable.
Valve locks should be inspected for excessive wear on the outside contact area as well as on the inner notched
surface. Any locks which appear worn or broken and its respective valve should be replaced.
Use a caliper to check the valve spring free−length
INSPECTION 465