new guy here needing help!!!

Whats up everyone? My name is Matt and i have a 97 honda civic Ex. i have had the car for about 3 years now and it has finally bit the dust on. i have few a mods headman headers and down pipe, high flow cat, 2 1/2 piping into tenxo r muffler, air intake, that is about it as far as performance. it is lowered 1 1/2 inches all the way around with coil overs, 17" fusion concept 7 rims, aluminum wing, graphics. the problem is that my car was knocking really loud and then stopped running. it would restart but it sounded really nasty. i broke the engine down top half first and checked out the head and valves and everything looked good. so i broke down the bottom half and the number 4 rod on the crank was free moving from side to side and up and down... i removed the rod and there is no bearing im not even sure if there is suposed to be a bearing there. i am new with this motor... i used to build old aircooled vw motors and they were simple. if anyone can help me that would be great... i am probable looking at a new crank and rods at the least... i also have another option of getting an f22b1 to replaze the old d16y8... is this a good idea and how hard would that be to do??? any comments would be greatly appriciated.. thanks matt