[SEL] Piston Ring Size

[Kerry]

G'Day All
I just pulled the piston out of an engine that I have that never had 
very good compression, bore not brilliant but its the rings I am 
questioning as when I pulled the piston out two of the rings looked too 
big and requires a lot of force to push them in by hand to anything like 
the piston size. The piston is 5.5 inch in Dia and the normal dia of the 
outside of rings is 5.75, is that two much, width is 3/8.
Thanks for suggestions

Kerry
Lithgow NSW Oz