Hi from Boise Mike,
A couple of things to look at here not knowing how much engine rebuild experience you have. First I think is the condition of the sleeve. Is it worn out? Is there a ridge at the top? Are the pistons worn? There should be between .003 and .0015 clearance between the piston and sleeve. This is a general rule and you should be able to find exact specs if you need to. At any rate there can't be too much play between the two. Are the ring lands in good shape? Someone will correct me if I'm wrong but I think .002 is recomended for clearance between the ring and piston. If they are too loose the rings tip in the lands and break easier. Too tight and they stick. Both result in early ring failure and leakage. Ring end gap, usually over looked. With the ring placed alone in the sleeve, the gap should be .003. Also make sure the ring gaps are staggered when you install them. And another "cute" things about this engine: Make sure the connecting rods go back in the right way. The engine won't turn if they are backwards. I know ;-). That should be enough to either help or confuse you further. Hope this helps.