Took off my valve covers the other day to find out if that was the source of my noise, and sure enough ALL my valves were loose(ty haynes manual for improper preload instructions) While redoing them to 1.5 turns past 0 degrees as per 60degreev6 suggested tightening specs one valve in particular won't adjust properly, to get it preloaded and not be loose the rocker wants to sit lower on the stud than any of the others by a rather noticeably large amount.

Then when I went to turn the engine over to do the 2nd pass on the other valves it suddenly wouldn't turn over, took me a minute to figure out that it was because of the valve...I actually managed to bend the pushrod, but I am actually wondering if it had already been bent and was perhaps the reason I couldn't get proper preload on that valve, so if anyone has some insight as to what the problem might be I would love to hear it, also wondering if I might have to replace that lifter as well?

 

/bump, really need an answer to this so I can get my engine back together and car running again

 

I'd definitely pull the lifter and inspect it. Hopefully you didn't tweak the valve also.

 

I don't suppose you know what caused the problem in the first place?

 

Not really. I haven't spent much time around the V6s other than the 3800 series. Most of all the ones lashes I've done have been either hydra roller I just set by feel with OEM rockers or solid rollers with actually running lash on it with a gauge. Maybe that lifter was just overly worn/soft and compressed when you tightened it for lash, then when you cranked it the cam lobe pushed so hard it messed up the pushrod. Either way I'd pull the lifter and inspect it. Make sure theres not something wrong with the camshaft side of the lifter also. You should be able to visually check the cam lobe with a flash light down the lifter bore.

 

Well w/e the issue is could happen with any engine, its not something engine specific...but yeah I guess I will have to pull the lifter...