I was always taught that when you tear down an engine with any time on it at all you need to replace the piston ring's(auto/truck)
IF you remove the piston from the cylinder as there is no way to get the ring back in the exact same spot. When a ring is seated it has worn into the little hill's/ valley's(small un seen scratches) of the cylinder/ring. If the ring is reused it will seat on the hills but that leaves low spots on the ring that will never seat and on the cylinder also if the ring/cylinder low spot's lined up.
So i have a few times tried to reuse a ring in our small engines and never had satisfactory compression return with out putting in a new ring
I have also read where people reuse the old ring and say it works fine. If this is true how are they doing it?
pat