100 mm Piston rings

[bleu951]

I tried searching for the answer but came up empty. Learned lots of other things though.

I need some 100mm diameter rings for a stock 951 piston that is compatible with the Nikasil bores used in the 964. The 964 rings fit, but I was wondering if the factory (965?) turbo was the same diameter and ring size as the 964. I would think they would be better suited to the blown application.

According to the PET

911 C2 Turbo rings are one of two part numbers:

930.103.968.00 for engine M30.69
930.103.925.20 for engine M64.50

Dimensions are not given, and I have no clue what the engine numbers mean. Since you guys are the 911 engine gurus, I figured you would know the answer.

Any help would be appreciated. Thanks.

For the curious, I had a 944 turbo block nikasil plated and used the 964 rings on the original pistons. I was trying to be frugal and not purchase new pistons. In hindsight, I should have gone for new aftermarket pistons with some real ring choices. The engine ran for a while, but was disassembled for reasons not related to the rings/pistons. I am trying to get the best solution before I put it back together again.