Gus

In process of rebuild and ordered a set of 993 pistons and cylinders. When I received i wanted to make sure that all cylinders were the same height group, but when I opened and took a look at the markings on the side of the barrel they were not the same as in the shop manual or other reference information that I have. There was NO triangle with the number 5 or 6 inside it , reflecting height group. Instead there was a etched or stamped large"A" or "B" with smaller numbers on the left and right - see picture, all have the number 6 in the upper right side and lower left. There is another number in the lower right side and upper left side. In addition there is another symbol further right of the "A" letter group with what appears to be an "m" and a number above and below, in this case the upper number is 712, hard to read the lower number but it appears to be 0211.
Does anyone know how to read this new number sequence and just what all means.
Bought 6 pistons and cylinders and set, verified item numbers on Mahle sight . Just have not seen these markings before.
Can anyone shed a little light on this//

stefan66

The numbers around the "m" are as follows:
- upper number indicates the Mahle plant
- lower number indicates manufacturing month and year - in your case February 2011

I had the same questions you had and found the information on an official Mahle presentation
Best, Stefan

Gus

Other item to address is that pistons and cylinders purchased from out side suppliers do not carry the same markers as a stock set from Porsche. I ran in to this when I did what you are doing as I was looking to insure my new pistons were in the same weight group. But ended up balancing myself.