I recently overheated my '95 Z28 6speed, it had always had tick and after it got alot worse. We first thought it was a collapsed lifter but we replaced them and stilll does it. Dad thinks its a valve guide? Pretty sure its in the valvetrain because it's defiantly not a rod knock(atleast I hope so..). Oils good no metal etc clean fresh still. Here's a short vid, just a shitty phone vid.

http://s12.photobucket.com/albums/a2...0804001530.mp4

*Note it doesn't sound as deep in person.

 

First thing I would do is pull off the valve cover and look for any obvious rocker/spring damage. The noise is loud enough that you should be able to pinpoint the noise to either side.

 

Pretty sure it's the drivers side. I didn't notice anything when I did the lifters but I'll have to take a closer look.

 

hard to tell by just listening to it but idk if that is valvetrain related.......to me i think is sounds like something in the bottom end.......maybe a broken piston ring landing or a burnt up piston......idk just a guess again kind of hard to tell from just that video....

 

Time to start taking stuff apart until you discover the problem...

 

Wouldn't I have bypass into the oil tho? Oil is still clean and fresh. Sound defiantly sounds like it coming from the top end on the drivers side. I guess I'll start there.

 

Use a stethoscope (harbor freight ones are about $4) and listen to the oil pan, and valve covers. Should be able to pin point a bit better by comparing the loudness of each spot tested. A screwdriver will also work but will not be able to hear the sound as well.

EDIT: also cut open you old oil filter. Check how much metal is in it.

 

To me it sounds like something in the bottom end but it's always hard to tell with a video. I would start by pulling both valve covers and taking a look to see if any of the rocker arms appear to be loose. Grab a screwdriver and put your ear up to the head and listen to each rocker individually to see if any of them are louder than the rest. Hopefully it's just a rocker or two that needs to be readjusted, good luck.