Belt coming off tensioner

[dstanggt50]

I finally got my car back together and running, but when I started it I noticed the belt was slghtly coming off the stock tensioner, coming close to teh vortech belt while running. When you turn the car off, the belt looks like it centers a little, but if you start it again, same thing. I was thinking either my tensioner might be going south, or possibly the belt might be a little long? The acessory belt that came with the s-trim was just to small, and had to get a 105 lenght belt, a little long, but it worked w/the car off. I'm pretty sure I've ligned everything up per vortech's instructions, so should I go down to the 104 size, you think that might help, or would the tensioner have anything to do with this if its going bad?

Thanks,

 

[fordtech28]

it can be either the belt or the tensioner get a smaller belt if it still does it then the temsioner is going south

 

[dstanggt50]

Just noticed something else, when the car is running the accessory belt seems to want to touch its other side that wraps around the water pump pulley. So I thought it was the belt, went down to the 104 1/4 size, but its really tight, I could barely get it on, would this be to much tension on bearings or anyhting? The tensioner looks like its almost maxed, might have moved a little.
here is the diagram for the belt:http://www.vortechsuperchargers.com/pdf/manuals/4FG218IM.PDF
its step 14, you can see the small gap in between the tensioner and water pump pulley, thats where they are wanting to touch with the 105.