Is this normal,my Subaru had a raping noise that I thought was an idler for the belt.than it would not idle and finally it would not start.code said 1 3 5 misfire.last attempt to start it ,it just stoked ,engine seized.removed timing cover and found lower idler sprockets,that drives both sides to have what seems like the bearing missing. Could it be the missing pieces are stuck in my pump ,I'll check tomorrow, I thought the timing chains lasted forever on these.how much from the pic is missing.