After being bolted together, the rod caps fit tightly enough that you can’t open them by hand. You can buy a dedicated connecting rod separator tool if you have the means. We didn’t, so we modified our bench vise to make it work like one. We unscrewed the jaw inserts of our vise and mounted them so they stuck out of the jaws far enough to hang a rod from them. We put heater hose over the inserts to keep from scratching the rods while separating the caps from the rods. Unscrew the nuts, but leave them so they are just barely engaged to the rod bolt. Tap on the nuts with a soft hammer to drive the rod from the cap.