Rattle noise after replacing spark plugs...

I just raplace my NGK/BMW spark plugs with new BOSCH SUPER plugs on my 95' 540i. While I had everything apart I replaced my valve cover gaskets as well. Just put it all back together tonight and now I'm hearing a rattle or a light knocking noise coming from the engine as soon as it is started. It's almost like the intensity of the noise will get greater then lessen and the pattern repeats itself as the motor is running. The noise doesn't go away. Any ideas on what this could be? Thanks in advance.

Double check to make sure your plugs are tight. That's what it sounds like to me.

same thing happened to me - I had overtightened the plugs causing a plug to crack - hence fluttering sound. I was very lucky to get away with it, can be a very costly blunder. Can also be caused by a loose plug ( and most often is ) , but make sure you haven't overtightened.

WARNING WARNING DO NOT EVER REPLACE PLUGS WHEN ENGINE HOT!
Just something important that I dont think was ever posted. Learned that when I had a bike. Bike news is common knowledge about aluminum heads, never change when hot. Lock, force, grunt, gone....helicoil. Dont forget this.

Good Point

I ruined a perfectly good R90S dual plug head this way. Got impatient, messed up the thread.