Please help me diagnose this noise

[Scywrath]

Hi,

The engine's bottom end has been rebuilt, I started noticing this noise after cold startups in the morning about 2000 kilometres into the break-in. I first noticed it after a 100 kilometre highway trip.
It goes away as the engine warms up, but it seems to be getting worse as the noise takes longer to go away nowadays.
All bearings and piston rings are new, crankshaft is stock ETA, rods and pistons came from an M52B28 nikasil block. The cylinders were "refresh honed".

http://www.youtube.com/watch?v=-qyW-aJeB_k

[jlevie]

Use an automotive stethoscope along the head, side of the block, and the pan to try to see where the noise is coming from. I can't tell what it is just by the sound, but it sounds like piston slap or rod bearing.

[Scywrath]

Use an automotive stethoscope along the head, side of the block, and the pan to try to see where the noise is coming from. I can't tell what it is just by the sound, but it sounds like piston slap or rod bearing.

Thanks!