Possible cam/lifter trouble, any ideas?



OK I'm back, thank Jack for this awesome forum.

and now for the important part,

first here's the run down on my rebuild C6 block maganfluxed, bored .030, new forged flat top pistons, Isky 262 hyd cam and lifters, rotating assembly(s) cleaned and balanced, matching head ported and polished, larger intake/exhaust valves installed, Cliffy port divider, Cliffy 6into1 header, original style rocker arms rebuilt, Holley 2300 500cfm w/Cliffy adapter(probably too much but still fun), this is what I can remember from off the top of my head.

And now my problem, it seems that after about 2000 miles on the fresh rebuild I had a tapping in my rockers so I yanked the valve cover and adjusted the rockers that were tapping, it fixed the problem...temporarily. About 2 weeks later the tapping came back and again I yanked the cover and adjusted accordingly, and then consecutively almost every 8 to 14 days since I had to yank the cover and readjust.

So any ideas?

I am thinking it is a lifter or lifters fouling or I am losing a cam lobe(s) otherwise I'm stumped, I don't have that much time left on the warranty so an immediate answer would definitely be appreciated.

Thanks again.
Chris Harris
Could be the adjustment is backing off because of a bad nut.. You might want to try a set of valvetrain locks (poly locks they are called sometimes)

If adjusting the valves seems to help, you most likely don't have a lifter problem, and it's definitely not a lobe.
I don't think it's just the backing off that's the problem especially when it's number 3 and 5 cylinders, after the last adjustment about 10 days afterwards, the tapping came back and the tone in my exhaust sounded different.

What I mean is the exhaust "pulses" have changed, they used to be uniform and in sync to the idle, but now it's just off.

Any other ideas?
Chris Harris
8) it does sound like you wiped a cam lobe or two, but check the adjusting screws on the rocker arms first as well as the normal tune up items. make sure the rest of the engine is sound first. also do a compression check. if the cyl's 3 and 5 are low, dry and wet, then do a leak down check and see if there is a gasket or valve problem. if not then likely a cam lobe.
Sounds like a bad adjustment screw on a couple of rockers. But worst case, it could be a lifter going bad or a wiped cam lobe. Check the oil for metal. If you see any silvery bits suspended in there, you'll need to fix it right away.
OK, thanks for the info guys. Here's an update on "Roxanne," yesterday (11/30) my dad and I yanked the valve cover and found that #2 intake and exhaust lifters, #3 intake, and #5 intake lifters are toast. There is only a couple of threads of adjustment on the rockers of #2, a little more on #3 and #5.

So just how fast should I pull the engine, take it to the "builder"(if you can call them that) and throw a "shit-fit" so they fix their mistake(yes I have the receipt w/cam card)?

Also I have an Isky 262 hyd. setup on the 200, has anyone found that the Comp 260 hyd. setup is any better? I only ask so that if possible have them fix the problem and trade up for a couple of extra bucks, (to the Comp setup).


Should I hold off and wait until I get my 2V head and have them do it all at once or just get what I need done?
Thanks again.
Chris Harris
8) it dawns on me that you may have a couple of bad pushrods. pull the rocker arms off and check the pushrods for bending and length.