Mike - I had same frustration on the 318. As I recall I wrapped some mechanics wire around the tensioner - looped over to a bolt installed in the passenger's side head ( someplace that would keep the wire in line) and used a screwdriver to twist the wire and suck the plate way the He''ck out of the way . OK way the heck is a lttle exteme - it was still a PITA to get the chain on, but only way I could get clearance. Not real sure if I could have cleared a needle nose vice grip jaw. It sure doesn't go on as designed out of the package!
The Suggestion is that 2 sets of hands are better than one - just make sure your helper didn't have a Garlic Pizza.