Sure they can. Which part would you prefer to break instead? I remember a pic that George posted years ago of the oil pump shaft twisted like a pretzel. The pin is cheaper. The broken pin is generally the result of another issue. While I am sure there exist defective pins, like everything else, usually another player is at fault and it is the safety weak link.
I suspect that the dist shaft is binding in the oriface above the timmerman collar.
I've been running HV oil pumps for 30+ years and never sheared a pin. Even while tracking Panteras with 50wt racing oil. Some say HV pumps shear pins - not my experience. I believe crap in either pump is more likely the culprit vs the extra strain of pushing addition oil.
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