well hes got 'grey' oil,? thunk 'in the motor when turned over by ratchet, and piston 'rockin in the bores' something amiss
got to be some kind of bearing ,material, cam /crank /rod/,
dead motor theat was hard to start, and no power when it did run,
tear apart recheck everything, replace all the bearings, rings
check and recheck of clearances , redo the timming
if the 'machinest ' doesnt have quality in his pockets to determine the problem as to what happened, then find one who does,