Check for warping of the cylinder head mating surface (see subsection «Detailed Specifications») using a polished ruler and a set of probes.
Sand the mating surface if necessary. in this case, it is allowed to remove a layer of metal with a thickness of not more than 0.5 mm. From model year 1978, the reduction in cylinder head height during grinding is allowed by no more than 0.3 mm.
Note. In the case of grinding the mating surface of the cylinder head, grind the contact surface of the upper cover of the timing mechanism drive to the cylinder block by the same amount.