Why would a Mercedes 280 smoke a great deal at start up?

Any engine that smokes during start up is usually caused by cracked/missing/worn valve seals and/or worn valve guides. This is due to oil pooling around the valve stem and being sucked into the combustion chamber.The good news is usually an engine will go along time like this because once it is running it is not usually a problem. In other words it looks worse than it is.