Normal copper engine bearings should be like this:
Are your bearings this kind ? This was the worest situation that one customer met, when he just receive goods to check.
No, not that serious, but become black with some spots after half or one year later in warehouse.
Engine bearing looks very simple, just two half circle metal, seem very easy to made. So some customers may buy beaing just depend on its price, for he do not know difference just from pictures at first sight. But in fact, good quality engine bearings that can meet engine work performance have very high requirement from raw material to manufacturing process, every process is finished goods process, if failed, this piece bearing is waste. Above two pictures are bearing electroplating problem, that may occur in small factories, usually these goods may be very cheap.