1st phase: 2.5 kgf/m
2nd phase: 4.5 kgf/m
3rd phase: -90º (loosen a quarter turn) + 4.5 kgf/m (then throw again at 4.5 kgf/m)
4th phase: + 105º (finish with angular tightening)
the first and second phase is clear, you make the 10 screws at 2.5 4.5.
In the third phase, what they send you is to loosen a room back to avoid the premature stretching of the screws and leave them again to 4.5 kg. In this way, they are tight in the established torque without tensions in the threads or torsions in the butt screws.
In the last phase, what they ask for is to pull with a goniometer and give the pair in degrees, it is more precise than to give it in kgf/mo in Nm because the torque value you are giving to the asparagus of the cylinder head is so high that it escapes the measure of the key, (about 12 to 15 kgf/m) That is why they give it to you in degrees.
It is even better to distribute the 105 degrees in two batches, for example, 4 phase +60º and fifth +45, because if we do not return to the roll of tensions in the threads and the torsions in the screws. In this way you get the same tightening but better distributed. Putting 105 degrees is a buried but ... for that the engineers think (although sometimes they screw it)
for example, in Opel they get 2.5 kgf/m +60º +60º +60º for gasoline, and it is how the screws are thrown best without risks, if you put a tighter of 2.5 +90º +90º Tighten 10 at the same time) and you put more torsion to asparagus without need.
Well, I hope I have clarified it a little (go bump)
greetings.
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