Without knowing what your rattle sounds like it's hard to give good advise.
Here's a sound file from Mitchpc of a paint can rattle.
From what I have read and from my own experience the cam gear rattle occurs between about 1200 to 1800 rpm when the engine is cold.
The catastrophic failures I've hears of happened below 10,000 miles. There have been several that had a repair done between 10 and 20 thousand miles and some that have had a rattle for well over 20,000 miles.
The oil pump drive chain makes a noise also but it's more like a sewing machine and it's not as apt to fail.
Not that it can't.
My engine has had a paint can rattle for about 7,000 miles. But just when cold.
I changed my oil last week. I put in Lucas 20w50 synthetic motorcycle oil. It sounds like a completely different bike. It still rattles well cold but not as bad or as long.
Rocket engines do make a lot of noise. One of our members said it sounds like a tractor FN a sewing machine.
Pretty fair description.
Draw your own conclusions. Hope this helps.