A while back, the Bearded Mechanic's Suzuki Hayabusa turbo project blew its engine, and while he had some ideas about why that might have happened, there's no telling for sure what the damage is until you take something apart. So naturally, because it's right in his chosen YouTube video channel name, that's what he did.
If you've ever fiddled with piston rings before, you know they can be kind of finicky. They seem both strong and fragile at the same time, probably because they're so small. Usually, there are very specific instructions about how you're supposed to orient them and gap them, and that's already true if you have a non-boosted engine application. Adding in the extra wrinkle of boost pressure to account for gives whoever's working on it (in this case, you) even more pressure to get it right. Pressure of a kind that probably doesn't spin or have a blowoff valve, but pressure nonetheless.
And the more pistons you have, the more you have to multiply your efforts, and simultaneously keep however many sets of parts straight that you need, depending entirely on how many pistons you have. Four pistons on this engine equals four sets of rings to keep straight.
Craig (the Bearded Mechanic) goes into great detail about the importance of piston ring gapping here, as well as proper orientation to make sure that the rings are able to expand the way they need to as the engine gets hot and things start to expand, as they do.
One thing that he noticed with the blown engine, you see, is that exactly one of the pistons actually broke. It appears that what may have happened is that either the piston rings weren't properly gapped and aligned, thus expanding improperly and breaking the top right off during some of the incredibly powerful 11,000 RPM pounding that piston was doing. A dropped valve may also have been involved; that part's not entirely clear, since it was only one piston that broke and not any more than that. All the rest, as a matter of fact, were fine.
As he starts to rebuild the new cylinder head, there's also a spacer involved (because remember, he needs to account for boost pressure). So then there's even more math involved later on in this video, because cam degreeing needs to enter the chat since the new cam center line has now shifted by a fixed amount due to the addition of that spacer.
If you're the type of person who wants to understand this stuff a bit better, or at least get your feet wet before you start jumping down additional rabbit holes to expand your understanding, take a little time and watch this video. It's fascinating stuff if you're so inclined, and well worth your time.
