I think my 02' Ford Explorer has sugar in the.

First, if the rings need replaced, the engine will need totally disassembled and checked. A knocking, however, usually comes from a rod or main bearing in the engine. Why do you think it is the rings? Does the engine run? Has there ever been a point where it doesn't start from the possible sugar contamination? I ask because sugar will prevent the engine from running, and it sounds like the engine is running.

Let me know.
Joe