Hey all,

So I have about 100 miles or so on my rebuilt 305 TPI, still in the break in stage. It has been running GREAT so far, has about 55-60 oil psi on startup and 30-35 psi when hot. This morning when I drove it, it was decently cold. After about a 10 minute drive and the car had warmed up, I heard a very faint tapping/tumbling sound coming from the engine. It is pretty rhythmic, and I can ONLY hear it at idle when warm, which I think is a good sign of not being rod knock since it doesn't increase with RPMs. It's not that deep of a tap, but it's not very light either. I also have a ticking noise, but it seems to be injectors. Oil PSI never goes below 30.

I can't tell that well if it is top or bottom, since i can somewhat hear it under the car on passenger side, but not on drivers side. I am leaning towards top end because of the rhythmic tumbling/tapping. I also seem to hear it coming from under intake manifold, so I'm hoping it's just a valve that needs adjustment. Any suggestions or ideas? Sorry if it seems I'm being overly cautious, but I put so much work into this rebuild and don't want to tear it down again!!

 

sounds like you need to adjust your rockers. prob have a loose one in there somewhere.

 

Thanks, I'm gonna try that tonight. How much damage could I have done by driving on a misadjusted rocker?

 

If it was just a tad loose, no damage was done; better to have a valve too loose than too tight causing it to burn. How is it after you adjusted the valves again?

 

could be a bad lifter what brand did you put in it?

 

check your exhaust manifold and y-pipe bolts. sometimes those metal donut things don't seal right, creating a small enough exhaust leak to seem like an engine tick

 

Also take a broom handle or short piece of stick and use it as a stethoscope on your top end where you think you hear the noise and that will give you a better idea as to where your noises are coming from. You can listen to your injectors or valves or the exhaust headers and get a better idea as to where to find your issue.