scrappie

When an engine overheats and seizes what exactly causes the seizure?
Do main and rod bearings heat up and expand so much and then lock up?
Do pistons heat up so much they expand in cylinder and lock up?
If the bearings swell up is the crank main or rod journals saved?
I realize the rods and crank heat up and expand themselves but are they ok once cooled?
I imagine hot enough causes warpage too?
Are the rods junk and does the crank need to be ground now?
I know over heating can cause things to crack also like heads but what about internally?
If a bearing spins does it mean that journal is bad or is it the bearing that fails or both?
I'm just thinking too much but like to know the exact ramifications of over heat or oil starvation.
I understand if metal enters the oil system then things are damaged and need to be ground or polished if possible.

1970greensupreme

a lot goes on. Heads/block warp, bores can be damaged, you'll actually see material transfer from piston to bore. Oil can break down damaging the crank and bearings. Cracks in block, heads. You need to pull it apart and have the block checked etc. I"m not sure what does more damage, running low on oil or overheat. It's a toss up

joe_padavano

Aluminum pistons expand more than iron cylinder walls, so eventually the piston expands to the point that there is metal transfer from the piston to the cylinder walls, and at that point the motor is toast.