i have made a discovery on my IROC. need you guys' help to confirm. when i bought her, she had a slight tick when cold at a certain RPM. it went away when warm. the previous owner (now a good friend, for obvious reasons 8) ) told me it was a rod knock beginning. i was kind of skeptical. well, then coming back from a Camaro/Firebird show my car was in (took 2nd place behind a rare '90 RS Vert in that one) the tick turned into a knock. i was a believer. fast forward to today. a guy who is buying a Toyota off of me who is pretty good with GM's (as am i, but another mind never hurts.) asked if he could have a listen since his friend (who had heard it previously) didn't think it was a rod knock. i said "sure" and fired her up. he revved her up (from underhood) and agreed with his friend, that it was top end coming from the left (driver's side) valvetrain. so i decided to go on a wild goose chase and remove the DS valve cover (hell, its the driver side, it aint that hard!) and looking visually everything looked ok. but then on a hunch of my own, i began to try and wiggle the pushrods. 6 felt tight and i couldn't move them. but two i was able to move and could SIMULATE THE SOUND!! i couldn't make it as loud, but it was the same sound. could this be the problem? could these severely worn out heads (smokes BAD on startup) be causing this faux rod knock? or am i just nutz?

thanks in advance!
Josh

 

if the push rods weren't tight why didn't you adjust the rockers/valves while you had the valve cover off, and if the noise went away, or got worse, you'd know you fould the source. as a rule what most people think is rod knock isn't. i'd investigate the loose rockers a bit more.

 

i didnt try and adjust them because the play is side to side, not top to bottom. it is like the other 6 pushrods have a sleeve (i know they do, can't remember the proper name) and these two do not, and it seems as if this is the problem...


Josh

 

they will move side to side if too loose, like everyone else said, pull the covers and adjust all the valves, it shouldnt be that hard to distinguish a rod knock from a rocker tap...

 

If you feel ambitious, might as well throw a few valve seals in there. It will eliminate the smoking