My car is an 87 300e with 159k miles. I developed a clicking noise originating from somewhere around the valves. Pulled the valve cover and discovered that one of the camshaft lobes was terrribly worn, and the others were on there way to a similar fate. The one lobe is so flattened that it comes to a point on one side. I have quite a few questions concerning my situation:

1. first, what could have caused this? I do have a oil leak, but I have always been quite meticulous with checking and refilling. I was under the impression that these have fairly hearty camshafts, so what could have done this? My girlfriend's dad, who is helping me with this project, has a theory. He noticed that each of the "bridges" (for lack of a better term) that hold the rocker arms is marked with a pin hole. 1 hole for the first bridge on the engine, two for the second, and so on. He thinks that a previous owner replaced only the camshaft, but not the rocker arms, hence the need to mark them. This makes some sense to me considering the cost of the rocker arms, and the fact that a new camshaft alone would make the car run pretty well for the time being, so he could onload it. Would there be any other reason to remove and mark the rocker arm bridges, other than replacing the camshaft?

2. What exactly is involved in replacing the camshaft and rocker arms? my girlfriend's dad seems to think it is fairly straightforward. Is it just remove rocker arms, remove camshaft, replace and your good to go? or is there a lot more to it? He also described some sort of method of tieing the timing chain so as not to have to adjust timing at all when the new camshaft is put in. Anyone done this with the timing chain on an M103?

3. Is there anything else I should replace or worry about being damaged as a result of this camshaft failure? Anything else that should be done while I have this part of the engine apart? (although I am reluctant to do anything else that will be very costly, as I am already low on funds from camshaft/rocker arm purchase). I already plan to change out oil and filter after project.

4. My oil leak is most likely the upper or lower timing chain cover, is there any reason why resealing this would be easier while the camshaft is out (doubt it), or should I do this as a separate project at a later date?

Thank you for your time, all replies are greatly appreciated,

Jay

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