Good news about the bolt - magic !!!
Seems strange that the engine is quite black when you've changed the oil regularly.
Assume the timing chain kit you bought was for the YH.
I got the kit for the YH.
I am assuming the blackness might be due to the wife's driving. I don't think she is getting it up to temp often enough.
Another question for people in the know.
Does 2nm make a great deal of difference when torquing the bolts. My torque wrench starts at 10nm and there are quite a few bolts that need only 8nm. Should I get a smaller torque wrench as well?