Need help with tensioner upgrade

[project 911]

So here's the picture.
Pretty much stock 70 2.2T that has been running with solid tensioners. I'm upgrading, but not going to the pressure-fed at this point.

I picked up the 930 tensioners with collars and a set of the wider idler's. See pic below.


When I installed the new parts I noticed that the tensioner on the right side had a copper shim washer located on the large shaft between the idler and the back side of the chain case (see green arrow in the pic below). Everything looks fine on that side.



On the left side there wasn't any shim at the back of the shaft. When I put the tensioner in place and tighten the nut, there is almost an 1/8" gap between the tensioner and idler. I can push the idler back and forth on the shaft (see pic below).



So... Am I supposed to have some kind of spacer/shim in there, or does the idler just fine it's own alignment within this free space.
Any advice would really be appreciated. It was in the sixties today and I really want to get back on the road.

[project 911]

Anyone? Don't know where else to turn...