This damage was due to fitting the bottom end bearing shells in the wrong way round. The bottom shell was fitted in the top half of the bottom end and the upper shell in the lower half. This meant that the bore in the con rod allowing oil to the piston pin and to cool the piston was blocked by the bearing shell.

After about 7 hours of operation the piston seized in the liner. The bottom end bolts failed as the crankshaft continued to rotate and the bottom end smashed through the crankcase causing a fire.

Although a bad design feature  allowed the shells to be wrongly fitted, The engineer responsible should have realised that the hole in the bearing shell now fitted in the lower half of the bottom end would not serve any function, and investigated further.