valve train help

motor has 27k miles on it. never had a problem before with anything in the valvetrain. sound started thought it was an exhaust leak so I changed header gaskets. still there so I changed collector gaskets. sound still there and getting louder, on both sides of engine. decided it has to be a valve noise. pulled covers rotated around to TDC and found #4,7,8 way loose. tried to tighten but out of threads on stud. first thought bent pushrod. pulled rods none bent everything looks to be in good shape but the Comp Magnum rollers are all floppy even when the threads are bottomed out. cam looked great when I had it apart a couple months ago and the oil is clean still. could I have three collapsed lifters at once? Point me in the right direction guys.
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Did you machine for screw in studs? Did you check for correct pushrod length?

Sounds like a press in stud getting pulled out by higher than normal spring pressure and lift. They yank upward on the stud the same way a claw hammer yanks a nail from a board. So, even tho you are bottomed, the stud has been raised enough that it changes the point of the fulcrum up enough to mess with the geometry.

I'd take it off the road before something breaks.

Good luck!

Its obviously off the road if I have the lifters torn off. I laid a straight edge across the studs thinking the same thing but the ones that are in question are actually lower than others that are adjusting fine. Like I said this motor has performed without a problem for 27k miles it isnt something that I did wrong during initial setup, everything was fine till now. No tramatic over revs or anything has happened recently I just drove it to a show and back home. I have good oil pressure and when I pulled the covers off each of the rockers and springs had an equal amount of oil on them.

Okay I found four lifters undercut at the cam surface, now what do I do? The cam from what I can see through the lifter bores looks okay just a little shiney. Can I install new lifters and call it okay or do I need to replace the cam? If I install just lifters do I need to do a break in like you would a new cam? what about a retrofit hyd roller cam kit? Somebody give me some good news Ive seen enough bad today.

I believe that you can just plop a few new lifters in there and be done with it. No genuine break in for lifters besides priming them once in the engine, they are hardened, very hardened. But... I do this when installing lifters and it's never failed me. When priming the lifters after installation, have someone turn the primer drill (if using one) and turn the motor by wrench nice and slow until you have completed 2 rotations, with the drill/primer going constantly, then adjust your rockers accordingly.

Should be ready for another 27K! [img]/phpBB/images/smiles/icon_tup.gif[/img]
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Lifters are cheap you might as well give it a try. I had a buddie do the same thing and his only lasted a few hundred miles but I think his cam was pretty scarred up before he tried it. Just keep an eye on them and pull them out if it starts to do it again. Keep in mind all that material has to go someware.
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Okay new lifters it is. I had planned on a new cam and heads this winter anyway just no need to break the bank right now Id rather save up the money first. Thanks guys.

Just to make me feel better I went ahead and threw on a dial indicator to see how my cam really is. Bad its very bad. Three lobes are flat .101 lift. So now I am cam shopping. Ill ask again is anybody using the retro fit roller cam set-up in an older small block? Desktop Dyno shows pretty big improvements by going to the roller setup over hyd flat tappet. plus no breakin worries or flat lobes. Ideas anyone?

I'm sorry buddy, but it gets worse. If the lobes are wiped, then you have metal in the engine. This just recently happened to me on my cleveland block. I also used the comp cams retro fit kit. Some how the dog bone for my #8 cylinder came lose and the lifters turned on me. I'm pretty sure it was in properly. The spider assembly was still tight. I still can't figure out how it slipped out because I couldn't manualy remove any of the other ones. The engine did see some high rpm's from time to time. So with less than ten thou on the engine, I tore it down to inspect the bearings. OUCH!!! You should have seen the particles embedded in the bearings! My crank needed to be turned, and my cylinders over bored.

If I was you I would take the time and inspect your bearings. If your lucky you'll only need to clean your parts and replace the bearings. I hope you have better luck than I have.

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All the cam bearings look good no scratches or anything, I pulled the heads to have them worked over some more and all cylinders look great, not a scratch just the original crosshatch pattern in them. I hated to spend anymore on cast iron heads but funds are dwindling down and AFRs just arent in the budget yet. I went with a hyd flat tappet just to keep the costs down. It was $169 compared to $800 for a custom comp retrofit roller assy. Its almost comical to call all these cam companies and hear how far apart their recomendations are on what I should be running. I got from .471 to .536 and 110LS to 114LS. Good thing I had my Desktop Dyno to play with or I would have been way off the mark and never have known the difference.