I can't tell if this is the water pump or timing chain or something else. It's not coming from the rocker covers.

Any ideas?

http://youtu.be/c02FigCUhi4

 

My experience with a similar sounding noise: I had what I thought was a rod knock, but went away above 2k rpm. I used a stethoscope and heard it from the opti so I think "oh well, another opti!" As I had 100k miles i figured why not put on a new timing chain since I have 90% of the stuff off for the opti. Turns out the stock timing chain was so stretched and loose that it was hitting the timing cover.

 

The noise really picked up after a short drive to the point where it's really bad. It has a metallic grinding component, but more of an aluminum than steel sound to it. The timing set is an LT4 extreme duty with about 15k miles on it.

I'm just going to start with the water pump and keep digging in further until I find the culprit. Thanks for the feedback.

 

Don't know if you have one of these but the metal probe allows you to contact the opti, water pump, timinig cover, etc while idling and you can really hear where it is coming from.

Save on Lisle 52500 at ToolTopia.com

 

If you have a cheap stethoscope pull the listening cup off and then take about a 1 ft piece of steel fuel line tubing or similar and stuff the listening tube to it. 3/8 fuel line worked great with a flange end to stuff the plastic listening tube into.
Then you can listen to each part.
Mine sounded like a grinding noise very loud on the opti front but could still be heard on the timing cover especially near wp shaft.
Turns out that the stock wp gear was used with the lt4 extreme gear set instead of the gear that came with the kit. The kit one is hardened the stocker is not or not as hard. After about 10k miles the gear was very worn and the timing gear had some distinct shinny wear patterns on teeth. The lt4 Ed wp gear should have only 3 holes in it as opposed to 5 for the stocker that is an easy way to tell the difference.
Replaced wp gear and problem was solved.