Attention: The manufacturer obliges car owners with a lot of wear on the camshaft and cylinder head holes to replace them without repair (grinding/boring). But some specialized workshops have mastered the technology of repairing the camshaft, which consists in fusing the necks of the camshaft with metal, grinding the necks, boring the cylinder head holes to install the repaired camshaft.
Support journal surfaces (arrows) and camshaft cams should not show signs of wear, but small scratches on the cams can be removed with fine-grained sandpaper or a block. The surface of the cams must be well polished.
Measure the runout on the center journal by determining the maximum difference in indicator readings per revolution.
The nominal runout should be no more than 0.02 mm, the maximum allowable runout is 0.1 mm. If the runout exceeds the allowable limit, replace the camshaft.
Measure the camshaft lobe height with a micrometer.
The maximum allowable wear is 0.2 mm. If wear exceeds allowable values, replace the camshaft.