Need help identifying an engine part.

I was wondering if someone could help me identify this part. It is the threaded part shown in the pictures. I know there is suppose to be a spacer there but dont know where to find the part or what it is called. One side is about 1 inch long and the other side is about 1/2 inch long. Thanks.


[img width=500 height=350]http://pccentralny.com/threaded2.jpg[/img]


[img width=500 height=350]http://pccentralny.com/threaded3.jpg[/img]