944S cranking problem

[1987944Sick]

after put new lifters and head gasket,my car wont start..

it cranks really slow and some times stops,and the cam chain moves up and down..

if i take a open end wrench on the cam and try to spin it,with the tensioner on,the chain tightens up at the top and it gets loose lower end..so one cam is moving the other one is not,then when it get really tight,it just shots the way i was going,and both of them spin..and the longer part of the chain is at the top again.and thats what it dose the whole time i crack or try to start the engine..it turns over then stops then slowly somehow turn again and just cracks slow..could it be that i stretched the chain out..dose it matter what side the chain is installed on..

i just wanna see if anyone on here had this problem..someone must have.