I considered that as we sat here and referred to "TDC" on the crank sprocket, knowing that wasn't exactly accurate. But since Rob wasn't pulling the head off, I figured he was not goint to probe #1 piston for actual TDC and was just going to align marks on crank/cams to get it all back in sync.

If he never seperated the cam sprockets from the cams, then I din't see any reason for him to even expose the back end aligning slots - just sync the marks.

However, if he DID remove the sprockets and needed to reference the back end slots to get it back in time, then I do have a question: If the slots are parallel, with the intake slot above center line and exhaust slot below center line, my assumtion has been that all three timing marks should be aligned on the "safe" mark (not actual TDC). Is that correct? In other words, the entire timing process, starting from scratch, is performed in "safe" zone rather than TDC, allowing the cams to be spun with carefree abandon. Am I on the right page?

I'm trying to learn as much as I can about these engines before Volvo goes to the next version.