Cam Question

[3ee4banger]

I was just wondering if anyone here new the sign's of bad cam bearings or what it sound's like could it be mistaken for a knock (after I do an engine flush it dosent make any noice it sound like a brand new engine but when it get a few thousand km the car makes alot of head noice no low end noice I do an engine flush every oil change) I've abused my engine because I thought it had a knock and i've been abusing it for 10000 km but there is no change in the way the engine sounds it actually runs better now and thats high rpm abuse the only reason i've been abusing my engine was because I thought it was already dead. It dosent even smoke any more the smoke stopped after I put a new cap and rotor on