I used to work at Rolls-Royce Bergen, former Bergen Diesel.
We delivered some crude oil engines to Sudan a couple of years ago.
The engine is basically the same as your common medium speed diesel, the ones we supplied were 320mm bore, and 360mm stroke, running at 750 rpm.
Crude oil places lot of wear on the injection equpiment, so nozzles and injection pumps must be replaced more often than usual. Apart from that, the engines runs as well as on heavy fuel.