Attention: The manufacturer obliges car owners to replace the camshaft and cylinder head holes without repair if they are heavily worn (grinding/boring). But some specialized workshops have mastered camshaft repair technologies, which consist of welding the camshaft journals with metal, grinding the journals, and boring the cylinder head holes to install the repaired camshaft.
The surfaces of the bearing journals (arrows) and camshaft lobes should not show any 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, determining the maximum difference in indicator readings per revolution.
The nominal runout should be no more than 0.02 mm, the maximum permissible runout is 0.1 mm. If the runout exceeds the permissible limit, replace the camshaft.
Measure the camshaft lobe height using a micrometer.
The maximum permissible wear is 0.2 mm. If the wear exceeds the permissible values, replace the camshaft.