To add a little clarity to this, there is a huge difference tearing down a LA, FP FOX or Brodak, than say a PA , JETT, Saito , and ones with pressed in bearings and other more complicated, some are very hard, even for master mechanics to take apart and reassemble , other are almost impossible without special tools. And YES I have seen several engines killed very badly by some that were engine mechanics by trade, mainly because the were unfamiler with the way they were put together, and some did not have the special tools needed..ie.. seat bearings and press them , removed pressed in sleeves, remove pressed in pins etc
Bottom line many engines are simple, some are NOT, and the Brodak shown with the casting flaws would not be fixed by 95% of modelers, that one needed a new case or a machinist to install a new front bushing. I have seen many more engines with what I call voids or blow holes that can be cleaned, and then have specs/chips/dots of metal come out of them and ruin an engine.
Randy