I have a 23GDLT which is bored I believe 30 over(Cant remember off the top of my head), Custom dual exhaust, 35vanny carb, port,polish, 3angle grind. Last time running it, It lost power and it shut down. So after inspecting it I realized the pushrods were just "falling" during rotation and so I tore the back housing off and found that the Cam gear had sheared off the shaft(right against the gear) and also obviously ate up the timing gear. I was full of oil and had maybe 10 hours on a service. So any ideas what the cause of the cam shearing may be? Oh and also it was a stock cam. Any insight is greatly appreciated.

Yeah, I mean other than it sheared some teeth on the timing gear and obviously when the cam separated it knocked the little infamous hole in the crankcase cover. Other than that I did not see anything else broken. Has the casting of the stock cams been an issue?

Changed a stock one out yesterday on a 36, worn down lobe.

I mean how can the casting process/materials be so inferior that a cam lobe is worn out??? I mean a good old chevy 350 could run for years and hundreds of thousands of miles and not have issues with bad casting in the cam dept. Not saying youre lobes werent worn or anything, just showing my amazement/stupidity for inferior quality japainwanesexico made junk today. I take it your PD was fairly new?

Briggs had a bad run of cams at one time. My 08 rounded the port cylinder exhaust lobe at 93 hours.

My 07 had a lobe go flat at 260 hrs. So who knows why some have no problems and other do.