Piston Crown Valve Contact Marks - BCY Engine

[RSPowerUK]

Hi all,

I'm currently repairing an RS6 C5 with a BCY engine and the previous owner didn't replace the crank bolt resulting in the crank sprocket slipping off resulting in a number of bent valves. I've cleaned the piston crowns using p800 grade and removed any high spots. All contact points are smooth to the touch.

Should I give them a further sand? I suspect over time carbon build up will fill in the marks?

Any thoughts would be appreciated, cheers

[Mɐʇʇ]

I think ok as long as the marks are not proud of the piston crown. Bits that stick up can become hotspots that could in theory cause detonation.

[RSPowerUK]

Cheers for the reply. All sharp edges have been removed. Engine is stock.