Help demon car from hell

[locoluna825]

I had got a 240 sx with a ka24E in it from a friend of mine for free, guy didnt know what was wrong with it (wouldnt idle). We were able to get it running, had the car for a while, and found out there was water in the oil, alot of water, after i had put water in the radiatar it magikly disapeared and abruptly died. Had it taken to a repair shop where they took the engine out, and from what i was told, one of the tensioners had broken off and damaged the water pump. they then fixed the tensioner, replaced the timing chain and assemply, water pump, and had a valve job done to it. Got the car back turned it on ran good then was greeted by a horrible chattering (not a rattling but chatter) sounds like a little diesel now and looks like it sounds like coming head, im affraisits something bad,also noticed when you removed the oil cap it would drop in revolutions as it was idoling. Tey said it was the lifters and it just needed to be ran a little while to get oil to them. week later the noise never went away i took it back and they said they something might have gotten plugged and would replace the rocker assembly. Finally got the rocker assembly replaced, AND ITS STILL CHATTERING its been in that place for 6 months now were kinda stuck on whats wrong.