S62 timing chain and guide removal

The main reason for the engine strip apart from we don't know the history, is to replace the timing chain and the guides. The s62 timing chain guides have a reputation for breaking apart, and to ensure this engine does not suffer from that issue, swapping them out no matter what there condition for new ones is a good maintenance point. Also this is one of the last times thats stoping the cylinder heads from being removed, if we decide to take that next step.