Rev if you have Issue No. 23 of High Performance Imports they go through installing Cam gears in the technical section.
The major point they make is :
"Be very careful; after each and every adjustment, turn the engine over by hand to ensure there is no interference between the pistons and valves. This can quickly make the whole task very expensive."
It also says to make sure the inner adjustment ring is set to zero.
And also to make sure that the bolts are nice and tight, so the gears dont slip position and make the engine stop.
Hope those little snippets of info helps