It is important to clean the head bolt holes in the block first. But I can not get into that.

I know on the M104 engines you torque them to the 55nm. Waite 15 minutes then you stretch the bolts by turning them 90 degrees. Wait another 15 minutes and stretch them another 90 degrees. Put a mark on each rocker so you don’t get lost as to where you left off. When your done each rocker arm should have three marks. One for when you torqued it, then one for each time you stretch it. I used some of my daughter’s nail polish. Oppppps! That's not spec. Buy new bolts and washers and it is important to apply oil to the threads and just under the head.