I'm guessing, 20-30 degrees tdc
That just may be the problem. Timing isn't something to guess at if you don't know engines inside and out. And, 10-20 is a pretty wide range.

If you were advanced too far and went into detonation, you could heat things up in a hurry.

How do you know the damper slipped? Guessing? The only way to tell is to get #1 to TDC and see where the timing mark ends up.