1. When re-torquing cylinder head do you loosen head bolts then torque or just torque without loosing? I saw a video from Heindl where they just tightened and was wondering if this is common practice.
Its non standard to need to check the bolts, I hesitate to use the cylinder head description as its a through stud that is cylinder and head (yes I know may sound picky but I run on mental pictures and I get off track) - but the manual does use the term Cylinder Head nuts.
Many are now one time use bolts. Ural is not fortunately.
Correct technical is you tighten bolts up equally in increments.
37 ft lobs (rounded off). First pass would be to tighten all up to 20.
Then 25, 30, 35 or 37 final.
However, these I think you would all only do if full loose nut found. If its tight but not fully, then a single is ok (and that is my take, any two mechanics could easily disagree)
Keep in mind, torque is lucky to get withing 25% of each set. Nature of the beast. Its no precise though precise values are listed.
What it means is if its roughly in the right area, then its good.
There are some advanced techniques used on some engines we won't get into that are more precise. I worked on Deutz engines that used a low toqur4e value that when you hit it, you then turned the bolt or nut so many degrees. Never talked to a Deutz engineer so I don't know if they felt that was better or the best you could do in the field (they sold a lot to non tech countries and a torque wrench calibration even if you had one would be iffy at best)
