964 Piston Indentification
 

Hi All

I'm having difficulty understanding the service manual description and how to identify my pistons.

The wordage taken directly from the manual reads: "Letter "E" in the middle (towards the inlet side), with identifier change level, internal Mahle code; the tolerance group (0, 1, 2 or 3) is indicated to the left next to the "E", with the weight group indicated next to the tolerance group.

Note:

The -- signs (minus/minus) for weight group indentification may also be indicated in a vertical plane. "

The image in the manual shows the top of a piston with the following markings:
0| E /2

What are they refering to when they say "with identifier change level, internal Mahle code"? I understand the tolerance group is "0" in this example, positioned to the left next to the "E". But the weight group (i.e. which I believe is the 2 in this example) is not next to the tolerance group. If it is the 2, then it would be better described as to the right of the "E".

In my case I have 2 types of piston stampings:
++3 E /23
0+ E /23

Which I interpret as the tolerance group being 3 and 0, but what is the significance of the "++" signs preceding the "3" and "+" sign following the "0". Also, if my interpretation of the weight group from above is correct, as being to the right of the E, what does it mean when there is 2 digits in this position, as in my case the "23"?

Your response is appreciated