Did another one - on a nearly identical car, the same color, even - yesterday and wrapped it up this morning. This one, using the lessons learned from the last one, went smoothly, but was still 10 hours' work. So far, all the ones I have had to do just leaked, but if one were to fail catastrophically and the timing chain bail off, it could cause some serious engine damage.

The lead engineer asks the question “Is it possible to repair this?” The required answer “Well, theoretically it is.” Good enough, design approved.