The M103 has small hydraulic "lifters", attached to the rocker arms. Over time they wear slightly and will cause a ticking noise on startup. The noise should disappear after 5 seconds or so. It the noise you are hearing does not go away, even with the engine running, it might be a worn timing chain.

The lifters are easily replaceable but a bit pricey. I have had an occasional ticking on startup for 5 years and it has not gotten any better or worse so I have not done anything about it. I suspect maybe one or two lifters may be weak and when the engine stops with the cam against the weak ones, they leak down and it takes several seconds for the oil to fill them up again.