I have a 2008 Ram 4.7 V8 with a knocking sound. Loudest during cold engine start up, then quiets but still there. I have had the top of the engine broken down and replaced timing gear and chain but could not find the knocking sound to that level. The sound appears to be lower but I cannot pinpoint where. Has anyone experienced this and have an idea of what it could be? Thanks for any help with this.

 

Welcome to DF. Gonna move this to the third gen ram section for ya.

Might try disabling one cylinder at a time, and see if anything changes, and when.

 

It reminds me of 98 F150 I had. It knocked really bad but once oil circulated through the block it was fine. This is actually caused by using a filter without an anti-drainback valve.

I can't say that is what is causing your issue but it's something to consider.

You have a video of the knocking sound from start to finish?

 

Oil filter could definitely be part of your problem. When is the last time you changed the oil and filter, and what brand did you use?
You had the heads off, I guess everything was clean?
How is oil pressure on start? Does pressure change as knock gets quieter?