Clean the surface of the cylinder head.
Put a straight edge (Item 1) [Figure 70-100-9] on the cylinder head.
NOTE: Do not put the straight edge across the combustion chambers.
Put the feeler gauge (Item 2) [Figure 70-100-9] between the straight edge and the surface of the cylinder head.
Put the straight edge on the cylinder head’s four sides and two diagonal as shown in figure [Figure 70-100-10].
The maximum distortion of the head surface is ±0.002 inch (± 0,05 mm). If the measurement exceeds the specification, replace the cylinder head.