Well, my 2.3-16 is in the garage for another rebuild, this time just to install a new set of pistons. I have the pistons and they seem correct but look different. The part number is 102 030 56 37 and they have the necessary indents for the four valves. As you can see from the picture below, they are a dished piston verses my previous pistons that had a flat crown. From my calculations, the volume of the dish is about 3 CC's which should lower the compression about a half a point (from 9.7 to 9.2). Since the engine is supercharged, I am happy with the lower compression but my questions concern what are these pistons? Are they standard replacement pistons? Did MB revise the pistons to lower the compression and are my computations correct? Are these pistons perhaps for the 2.5-16?

Interesting, anyone have any thoughts?

__________________
Jim Villers
190SL, 230SL 5-speed, 95 E320 Wagon, 01 E320 Wagon, MGB, Boxster 'S', 190SL "Barn Find"

Sorry, I forgot to attach the image before posting.

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__________________
Jim Villers
190SL, 230SL 5-speed, 95 E320 Wagon, 01 E320 Wagon, MGB, Boxster 'S', 190SL "Barn Find"

Jim,
The OE oversize 16V pistons have the dish. With 0.5 OR 1.0mm overbore that dish is required or compression goes way UP. IF you have 22MM piston pins OE compression id 9.7/1.

__________________
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190E 2.3 16V ITS SCCA race car (sold)
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Retired Moderator

Thanks ... I have a 1mm overbore piston.

__________________
Jim Villers
190SL, 230SL 5-speed, 95 E320 Wagon, 01 E320 Wagon, MGB, Boxster 'S', 190SL "Barn Find"