Valve Spring

CAUTION: Visually inspect the valve springs and replace them if damage or abnormal wear is evident.

Measure the free height of the springs. The springs must be replaced if the free height is below the specified limit.
Standard: 44.6 mm (1.7559 in)

Limit: 43.6 mm (1.7165 in)

Fig 1: Measuring Free Height Of Valve Spring
Courtesy of ISUZU MOTOR CO.
Measure the valve spring squareness with a steel square and replace the valve springs if the measured value exceeds the specified limit.
Limit: 2 mm (0.0787 in)

Fig 2: Measuring Squareness Of Valve Spring
Courtesy of ISUZU MOTOR CO.
Using a spring tester to compress the springs to the installed height, measure the compressed spring tension, and replace the springs if the measured tension is below the specified limit.
At installed height: 35.0 mm (1.38 in)

Standard: 196 N (44 lb)

Limit: Less than 181 N (41 lb)

Fig 3: Measuring Compressed Valve Spring Tension
Courtesy of ISUZU MOTOR CO.