Couldn't get my damper in very well, so I emailed Shoe...his reply:

Ah. You have the same problem as me - I had a little bit of rust build up in
the threaded hole on the engine block.

What you can do is spray a little bit of WD-40 in there (very little) and
use a pipe cleaner (or come up with your own at-home solution) to provide
some friction. Then you can use a little lock-tite on the bolt to prevent it
from backing it.

Without spraying a little WD-40 I too was unable to get the bolt all the way
in. This has only happened to one other person besides you. Strange.

I guess it happens infrequently, so be on the lookout!

 

this was already discussed in the engine damper thread.