Hi all, is there any reason why I cant change the tensioners on the timing chains? What is involved with changing the upper tensioner? Is the upper the one that is a bolt on the back of the head? As you are no doubt aware I am a novice with these motors but am a reasonable diy mechanic so I don't see why the chains have to be changed as well as the tensioners? Could I change the lower tensioner without removing the gearbox? Thanks for your help. Steve