I NEED SOME HELP/INFO/ADVICE!!!

Let me provide some background info on the problem.

Car - 1993 190E 2.3 (CA emissions)

Head gasket blew Jan 2000 @ 150,000 miles. Replaced head gasket and had a valve job and head surfaced while the head was off. After putting it all back together and receiving assurance from the machine shop that the head was not warped/damaged in any way, at the 1000 (approx) mile mark the camshaft broke (oem cam). No one could provide an adequate explanation for this except that it was an extremely rare occurrence. I learned from my parts place that this was a fairly common incident in Europe (2.6 engines also) and that MBenz wants to keep it quiet so they don't have to do a recall, don't know how true this is however. After again removing head/intake/etc (what a pain in the %$#) replaced camshaft with aftermarket hardened steel camshaft, low and behold at the same 1000 (approx) mile mark again the camshaft broke. SOMETHING is definitely wrong but I don't know what and nobody else I know that is mechanically inclined has a clue either. If anyone knows the problem/cause or has the cure or any other helpful info please reply.

Unless I can figure this mess out, I am contemplating replacing the head/cam and going from there, or possibly the entire engince and/or replacing the 2.3 with a 2.6. Thank you in advance for any response.

Rick