Pontiac Repair: top end knock, possable, quad 4

Question
1996 grand am quad 4, when i start it it sounds normal, but when u rev it up to 2000rpm theres a hard knock in the top end, rev it pass 2000rpm and the knock goes away, tore apart the timing chain to inspect it and everything looked good, then i droped the oil pan replaced the oil pump put it all back together but the knock is still there. thinking it might be a collapsed lifter? is this possible????

Answer
Hi Jason:

Yes it's possable but it will not knock it wil more than likely make a ticking noise. I have ssen the housing the lifter go in to wear out and make noise as well when you take it apart inspect for ant scoring in any of the bores where the lifter ride in.