Maybe tappet noise? If it goes away, when the temperature gets warm enough, that may be it. I don't know how it should sound when the pri. tensioner goes, but when the sec. goes, the noise should last only for a few seconds at most (until oil pressure builds up). Tappet noise lasts until the engine gets warm (so valve parts warm up to decrease mechanical gaps). This engine does not have hydraulic lash adjuster, so it does tend to make tappet noise, I think.

Anyway, you should talk to someone who know the sounds...