When
the washer fails, the rod gets hot enough to severely distort it and
lock the engine. .... There is no
indication of a lubrication failure either (all the engines are oil
injected).

Overheating big end, hmm ?
What makes you think this is NOT a lubrication issue ?

Regards,
Gilles Thesee
Grenoble, France
http://contrails.free.fr