Its a 95 240sx with 185k miles on the original motor.

i had the infimous marble sound. took the timing chain guides off. went away for a little while then heard it again. thought maybe the tentioner was bad so i replaced it and cleaned out the hole that oils the tentioner. Now its not as bad it only does it REAL bad when it first starts. So i thought maybe the oil pickup is clogged or the oil pump isnt working good enough.

Any ideas? am i on the right track?

thanks in advance...