When Leroy Cox ran the show every engine was assembled by hand in a "clean" room with the temperature controlled so that each piston was a perfect match to the cylinder that it went into. After the company was sold that was no longer the case. Engines were tossed together and none cared if they ran or not. When swapping parts from old engines always keep pistons and cylinders together as a set. The old Cox engines were so good, because of the "clean" room, that they bumped all other 1/2a engines off. Fox, Anderson, Holland, Olsen and Rice, K & B, OK, Jim Walker, .........no one could compete. You give that operation to a JUNK company and they make JUNK.
By the way, when I worked for Cox I saw the clean room in action, it was real.
Larry