Ticking in valvetrain w/acceleration only

[patzky1]

I have a sbc with over 100,000 miles on it and it has started to develop a tick in the valve train whenever I accelerate, but not at idle. It seems to only do it under load and it appears to only be on one lifter by the frequency of it. So, I took off the rocker covers and did a running valve adjustment with 1/4 turn preload on the lifers. Still does exactly the same thing. A friend says to simply add more preload since the engine has hydralic lifters (it does), but I'm skeptical and don't want to break anything earlier than I have to.

An additional tidbit of information would be that when I'm at highway speed (350 auto tranny) the enging shudders at regular intervals and is noticeable. This has all started only since I first started to hear the valvetrain noise.

So, what do you think? Bad lifter? Is it possible that I have a sticking valve that is causing it? Worn off cam lobe? Any thoughts/suggestions greatly appreciated.

Pat

[Guest daZda rally]

Have you checked for a small exhaust leak at the head? Is the same frequency as valve train and makes a 'tick' noise only under load. Can be hard to find the leak but loose or broken manifold studs are easy.

Peter.

[patzky1]

WOW

Thanks, daZda.

I fee like an idiot since I went out and looked at the manifold and, sure enough, there was a small black mark on the white hooker header gasket where there was deterioration and a leak. New gasket, and viola! A word for the wise, you may consider actually getting good gaskets when you buy a set of headers if they come with the fiber ones. This gasket was only 2 years old and had already "worn out," something completely unexpected from my point. I'm sure glad that I didn't need to replace the lifters! Pat