Timing Chain & Camshaft




I am planning on replacing the timing chain, chain tensioner, camshaft adjusters, and camshafts on my E300 M274. It has the infamous rattle on startup and was looking to do the job my self seeing it's pretty straight forward with the right tools. I just cannot find the answer anywhere as to whether or not when replacing the timing chain can I leave the camshaft lock down tool on the camshaft and then rotate the crank to pull the new chain in or do I have to completely remove the camshaft and then rotate the crank?
In the MB service manual the pictures show that there is no camshafts and no camshaft tool when snaking the new chain in.
Only reason I am asking if the chain can be replaced without removing the camshafts is because: 1) I do not want to mess with the timing/position of the camshafts too much, and 2) I've seen a couple of videos on YouTube snaking the chain through on M270/M271/etc engines that are all "Interference" engines and should not able to do such a thing.
Any help is appreciated!


