Question

cylinder head bolts need to be tightened in several phases.
why?
in this way, the cylinder head is clamped evenly to the lower block.
in this way, the cylinder head bolts will not break.
in this way, the cylinder head bolts are stretched to their maximum.
in this way, a more accurate clamping force is achieved.

Explanation:

Tightening cylinder head bolts in phases ensures even clamping (prevents warping), reduces bolt breakage risk (gradual stress), and allows for accurate clamping force application. Stretching bolts to maximum isn't a goal; controlled tightening is.

Answer:

In this way, the cylinder head is clamped evenly to the lower block.
In this way, the cylinder head bolts will not break.
In this way, a more accurate clamping force is achieved.