More info would help in assisting you. Did you only install new rings? Did you check the pistons and bearings clearances in the engine? What is the gap on the rings? Did you use plastic-gauge to check the main and rod bearing clearances? Here is a video on plastic gauge if you are not familiar. Ring gap, piston clearance and bearing clearances are needed to do a successful rebuild.
https://www.bing.com/videos/search?q...RS%26ajf%3D100