95 2.2 cavalier engine noise

I have a 95 cavalier 2.2L with an interesting problem at 184000km. Half a year ago I noticed a ratling, clancking metallic noise from the engine. It became very bad as rpm was increased. So I took the oil pan off to take a look and found that the camshaft was busted. So I took the whole engine apart. One of the lobes on the camshaft (left hand cylinder if you are facing the car) was badly eaten away, another not as bad. But the interesting thing is that the damage was not on the lifting side but after the apex of the lobe! Well anyway, I got a new cam, new hyd lifters, new valve springs(thinking they were not strong enough to keep the hyd lifter followers following, hence the damage). While I was at it, I checked the valves as well, all are fine. Suprisingly the interior of the cylinders were almost like a mirror! No wonder it eats no oil, has low gas consumption. The cranck and piston assembly were all firm, smooth moving. Fat, dumb and happy, I put everything back together again....
But, I still have a knocking sound at low rpm, fine at medium and high rpm. Load on the engine is not a factor, just rpm. I started adjusting the valve lash. As I rise or lower the nut holding the rocker arm down, I found, on a warm engine, 7/4 of turning is where the hyd lifters can adjust their lash, they adjust after a second or two after an abrupt 1/4 turn, so they are good. So I set them 2/4 from the top on a cold engine (oh yeah, this was done while the engine was running! Big mess, but some cloth helps). That did no change. I played around with different oils and filters, no change. It is definetly not the transmission. It is the engine. Sounds like marbles in the engine at low rpm. WHAT THE HELL IS GOING ON?! CAN ANYBODY HELP?

your answer is puttin a timing chain and guides in your engine, the amount of play should be no more than 8mm's. don't go cheap and replace just the guides, do the gears, guides, chain, your clattering noise will disappear