Has anyone experienced piston slap on a B230? If so, what exactly does this sound like? I am experiencing a knock upon cold start that I thought was detination, but there has been no change even with drastic reductions in timing advance. The sound only occurs upon cold start and is worse as ambient temps fall. above ~50 degrees F there is no sound at all. The car never did this untill I rebuilt the head over the summer and had it milled due to warpage. Needless to say it never knocked untill the weather turned cold. any thoughts ?

Milling an overhead cam engine changes mechanical timing ! That which is relative between the crankchaft and pistons and the cam and valves. Changing the elictrical timing won't solve the problem. Get an adjustable cam gear and hire a professional tech.