I am in the process of changing my timing belt on my 91 civic si and I was wondering if you put the timing belt one tooth off and then turn the crank to tighten the belt, tighten the tensioner and it should be dead on. Correct? If not then after you tighten the belt it will be off? correct?

 

No. There is not a tooth's worth of slack in the timing belt before it is tightened. Leave both gears at TDC.