Hey all,

just finished my 305 rebuild and have it back n the car. It runs good, already set the timing. The problem is, I'm getting a loud clacking/tapping noise coming from the front of the engine on the passenger side. It seems to be a rocker, but I can't tell. It sounds like the #2 cylinder. So I took off the valve cover and adjusted the valves when hot, and the noise still didn't go away. I kept trying to tighten it down, but I was starting to make the motor die. I don't think it's a sticky lifter... it has all new lifters and we hot tanked the block. Any ideas? it's definitely coming from the top end, and oil pressure is 55psi cold and 30psi hot. And the sound is constant with rpms, I just hear it at idle better because of engine noise. It is pretty loud though. I didn't see anything weird when I had the valve covers off either. Any thoughts? I want to get driving my car again, but I don't want to damage the engine.

 

What happened when you adjusted the valves with the engine running?

 

The tapping didn't really go away that much, and it eventually got to the point where I was tightening it down too far and was about to make the motor die.

 

Tightening the valves past zero lash ALWAYS makes the motor die.

Go back and re-do it, except this time, do it RIGHT.

Adjust each one to zero lash, one at a time, as quickly as practical. Don't try to add the preload while it's running; just get all of em to zero, and to shut up. Go back over em acoupla times to get em PERFECT if ya have to. After all, "perfect" is just ordinary, the minimum acceptable standard; we start there, and look for all possible ways to improve, right?? Then shut the engine off and add your preload with the engine not running. (the nuts will turn a half turn or whatever, the same with it sitting still, as with it running... no really, they will, they can't even tell whether it's running or not)

 

Thanks! I'll try that. Though it didn't seem to quiet down much even before I overlashed them. Could it be something other than a loose rocker?? Exhaust manifold loose, or something worse? thanks for your help sofakingdom

 

Leaking exhaust manifold or header gasket will sound just about like a valve clicking.

Stick a length of hose to your ear and touch the other end to the valve cover and move it across cover, then around the exhaust manifolds..

Or even a metal rod, screw driver, etc will work the same way.

When you get to the item making the clicking you will hear it much louder through the hose/rod/screwdriver.