To Bill Gum, If you want to save money rebuilding your engine, You can install new sleeves and have them bored for you std. size pistons. You can buy the sleeves for about $21 each. Rings are about $27 per cylinder.If you can go this route,the grooves in the pistons must not be worn too much.
Here are tolerance limits for your pistons;
Top groove side clearance--0.100-0.132mm when new.
2nd groove side clearance--0.070-0.102mm when new
3rd groove side clearance--0..30-0.062mm when new
The wear limits are the figures that you should be concerned with . If the grooves are too wide,then you must use new pistons,or you can have spacers installed in the grooves and have the grooves machined to the new limits. I have always installed new pistons because there is not a machine shop in Lexington that I would trust to do this close tolerance job. You may be more fortunate where you live. You can check it out. Keep us posted on your progress.
Bill Lewallen Lexington,Ky.