Valve Spring: Testing and Inspection

Legend
Installed length, dimension "A"

1. Assemble shims, valve spring support, valve, valve spring cap and valve keepers with an accessory spring.
- Use a accessory spring for testing purposes assembly, e.g. spring for oil thermostat (engine 928), part number 928.107.171.01,

NOTE: If required, the spring may be shortened slightly to facilitate assembly.





2. Using a depth gauge, measure vertically from valve spring cap to surface to valve spring seat surface. Record measurement.





3. Determine thickness of valve spring cap. Record measurement.
4. Determine Actual Demension

Example: for determining the actual dimension:

Inlet valve spring
Measured value 37.8
Thickness of valve spring cap -1.6 _________
36.2

Result: The value of 36.2 is within the admissible tolerance.

NOTE:: Take care not to confuse the parts after the measurement.

Installation Dimension Specifications
Inlet valve A = 36.1 + 0.3 mm
Exhaust valve A = 34.7 + 0.3 mm