Timing on N62 4.8is.

[craigatkinson]

I am timing my 2006 4.8is n62 engine. I have the engine out of the car. I got the timing in perfect position with the special tools. I tightened everything down, checked and rechecked to make sure there was no gap between the special tool and the cylinder head. I decided to check to see if it would stay in time, so I spun the engine around one time back to TDC. I locked it back at TDC again, and rechecked the timing, and there is no a big gap between the special tool and the cylinder head. Way more than the .5 mm that they say is allowed. Why would it do this? Is my engine not timed right? Any input would be appreciated. I'm shocked how little information here is about this on the internet. I'm making a youtube video as I go along so that I can share when I'm done. Hopefully I can provide some information that is currently lacking on the internet for DIYers.