illgoblind

My wife’s 1996 vette has LT1 with 148,000 miles on it, it has developed a tapping noise under the valve cover, the performance has not changed but after removing the cover I narrowed it down to one rocker arm, while the engine was running I used a wooden handle to push on the push rod side slight change in sound but when I pushed on the valve side while running the tapping noise whet away. Would this be a lifter? I tried to adjust the rocker but no success. I remove the intake and pulled the lifter there was some gulling in the roller but the cam looks good, could this of happen when I tried to adjust it? Now I’m about to put a new lifter in it how do I adjust it? What is the procedure??

redbullapril23

idd you check the pushrod for valve lash. if its a tappin sounds like the rocker arm is loose. if you replace the lifter and it fixes it then you prob had a bad lifter. as these are hydraulic lifters and if the oil passages get clogged they dont work and will cause the roller on the lifter to freeze up. make sure you check installed sping height and do that all to specs. shoot me a pm if you need the lt1 specs i have a 1996 vette too.
your friend

Sean

redbullapril23

opps also the hydraulic lifters should adjust them selves... as they fill with oil.
now you have to adjust the valve lash with the valve closed aka the lifter all the way down.

make sure u soak lifter in oil b4 installin.. and put lots of oil on the rocker b4 start up just to double check.

do you know how to check valve lash?

illgoblind

i remember the old days of adjusting my rockers was...with the valve seated tighten the rocker down so that i could still turn the push rod and then after starting the engine tighten till rocker chatter is gone and turn one 1/4 turn after, this is the first time i have fooled with these roller lifters thanks for your help

redbullapril23

yea. i like adjusting with engine off. i mean u can do both.
i just dont like the idea of another way for me to get hurt or make a mess.
later
Sean