I was hearing a rattle around the timing chain area that I thought went away after I replaced the chain tensioner - it's been roughly ~900 miles since I replaced it. I completed a track day yesterday and the noise is back today. Is it the timing chain tensioner again or something else? I heard the noise the first time after getting it dyno tuned, and now after a track day. Mods are 15% pulley, RMW dominator cam, intake, and 550cc injectors. Any ideas guys?

Here's a video of the rattle:

 

How many miles on your car?

 

It's at 106k

 

Be sure that it's not the belt tensioner or idler pulley making noise. If not, there's a possibility that your chain rails are worn to the point that the tensioner won't take up the added slack. Carefully use a stethoscope with a long probe to better locate the source of the noise.

 

I didn't even think about using a stethoscope! Great tip. I think I narrowed it down to the belt tensioner, but i'll have someone with better ears come over tonight to confirm. That should be a fairly easy swap that I should have done when I installed the pulley. Thanks!

 

Just an update - I replaced the belt tensioner + idler pulley and it solved my noise issues. The belt tensioner strut was completely blown out spewing oil all over the timing chain cover, and the mount on the strut was cracked so it rattled around as well. The engine feels so much smoother now! Thanks for the help