The engine is new, the spark was advanced ok and it was not petrol, was ethylic alcool.
The hole at that position, pointing up to piston, was in a position where the oil film must be the strongest possible.
besides oil scaping the presence of a hole itself in that position generates heavy turbulence that brakes the film.
I posted my problem couse I judge an 'engineering absurdity' a hole in that position.
The prop used was apc 17x8.