First, if you have to pad paper, you should theoretically pad paper on both sides, so that the center distance between the two holes of the connecting rod will not change too much. The center distance between two holes will affect the compression ratio of the engine. But it's not needed now. They are all standard tiles. If it is an emergency, you can.

Second, the crankshaft connecting rod introduction:

Crank drive system is the main motion mechanism of engine. Its function is to convert the reciprocating motion of the piston into the rotating motion of the crankshaft, and at the same time, to convert the force acting on the piston into the torque output by the crankshaft, thus driving the automobile wheels to rotate. The crank-connecting rod mechanism consists of piston group, connecting rod group, crankshaft, flywheel group and other parts.

III. Schematic diagram of crankshaft connecting rod: