Valve Spring Service
prolonged use, valve springs tend to weaken, lose tension, or even break. During engine
service, always test valve springs to make sure they are usable.
should be tested for uniformity and strength. The three characteristics to check are valve
spring squareness, valve spring free height, and valve spring tension.
spring squareness is easily checked with a combination square. Place each spring next
to the square on a flat surface. Rotate the spring while checking for a gap between the
side of the spring and the square. Replace any spring that is not square.
spring free height can also be measured with a combination square or a valve spring
tester. Simply measure the length of each spring in normal uncompressed condition. If it
is too long or too short, replace the spring.
spring tension, or pressure, is measured by using a spring tester. Compress the spring
to specification height and read the scale on the tester.
pressure must be within specifications. If the reading is too low, the spring has weakened
and must be replaced.