I had some problems with my pistons being worn out.
I have a spare engine an have taken the piston from that one.

The old pistons have 3 pistons with letter B and one with letter C.
(It is also stanced the letters in the block)

The "new" pistons have 3 A:s and one B.

I cant see any difference of them, anyone knows it there is any difference?
And in ePER I only find A and C pistons.

Any advice would be appreciated.

Pistons after casting and machining in the factory are not the same size, there are slight differences in the diameter, few 0.001 milimeters, and the pistons are stamped with groups/ wth letters A B C etc. and the block is bored considering the piston sections, so new piston C should replace old C , B to replace B etc. but if the bores are worn out piston groups may be irrelevant