@matti7771 Matti, the tensioning device is essentially the pulley and the
shims. If you think of how a pulley squeezes the belt, the less shims, the
further apart the pulley is from the fan, and less or more tight. So in
this case if he used no shims, that would be the "tightest setting" since
the pulley will directly squeeze against the fan, when fully tight would be
tighter. If you used 3 shims it's then spaced, and the belt would go lower
on the pulley. Hope that clarifies.
I know this is way old at this point but I figure somebody might see it.
The last time I had big issues with my '91 911 there were no awesome videos
like this on the web! But... the fan belt shredded yesterday so I was
investigating the situation and found your video. I suppose you've solved
the shim problem of needing less shims... This is what i found elsewhere:
Less shims belt rides higher/tighter. From pelicanparts fan_belt_911
article... Enjoy the road!
You must have 5 to 6 shims on the fan shaft at all times !!. Shims tip the
top of the pulley into the fan to tighten belt. If you remove shims off of
fan shaft pulley will wear out. You adjust by taking shims from in between
pulleys and move one or two shims to outside of shaft. If you take away
shims off of shaft the nut tightens on shoulder of fan shaft and not the
pulley.
I have the same situation. I don't see how tightening the outside pulley
half with no shim between them would make the belt tighten ; there is no
space .