Thank you all for existing and being so helpful. A friend and I began the task of replacing the head gasket today on my 89 240. It was noticed that there was a chip about 0.25" in width on the shaft. Not on a lobe, rather right up against the timing belt gear. I am wondering about a few things upon this discovery. Firstly, what would cause this part of the shaft to fracture/chip off? We noticed that the bolt holding the gear in place was VERY tight - in fact we were not successful in removing this bolt. Perhaps this was overtightened previously to the point of fracturing and eventually chipping? Secondly, where is that little chunk of steel now? That's a bit worrisome to say the least. And thirdly, is it necessary to replace the camshaft upon this discovery? Otherwise, it looks to be in excellent condition with 176,000 miles on the motor. My concern is that with this compromised shaft connection point with the t-belt gear, could further fracturing/breakage occur? This would obviously be a disaster! I am concerned about catastrophic failure!