Well I think I figure out what caused this.. the initial issue was a few months ago when my eccentric came lose and unscrewed the cam bolt. I had it at that time with my mechanical pump and pulled the eccentric out. But when the came bolt came loose it was enough to push the cam back into the block a few mm to make the adjacent lobe impact the front of the neighboring lifter. This explains why every lifter has a slight blemish or a full crack on the front side of the lifter but not the back. What clued me into this was the fact that not only was the casing damaged on the broken one but the pin had a wear mark in it that was in an arc which meant whatever was hitting it was rotating. I looked at the came and there is no apparent issue there so I think I am safe there. Oh well.. Live and learn. New lifters will be here tomorrow
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