2.0 Pistons. 906 in a 68S???

[demo]

I have a set of P&C from a 69 911S. The pistons look exactly like 906.
Cyl. #80ZD3, piston #80P26. Anyone have any opions or facts about these>

Stephen www.route30classics.com

[preS]

What kind of liner does the cylinder have? The 906 pistons and 69S pistons are identical.

Richard

[demo]

Not from all of the pictures I have found on the net. 906 are decidedly bigger valve reliefs, suppose to be 10.3 - 1 ratio, and have a ridge on the top of the piston. Search 906 pistons, and you will see what I mean. Also my friend Ralph Meaney still has a piston he ran in his 2.0 914 at Daytona 24, in 1970. Its exactly like mine, and not a 911S

[demo]

304678, please noe the differance between S & 906 pistons.

[preS]

Stephen it was my understanding that the 69S took the pistons on the lower picture but have never taken apart a 69S 2.0L.

All the pistons that I have (used) are as on the lower picture. A few cylinders are different in respect of lining, I believe it's called chromosil. The lining has tiny holes to hold oil. I thought that those cylinders are 906 and the regular steel lining (as on the picture?) 69S 2.0L.

Richard

[tom1394racing]

It is my understanding that the pistons used in the 69S are identical to the 906 pistons.

The Mahle part numbers that can be found under the dome are as follows:

1. 69S - 80P26E
2. 906 - 80P26

Here's pics of each, two pics of the 69S first and then a pic of the 906.

[ajwans]

That explains why 69S had higher compression than 67-68S.
I wondered about that.

andy

[preS]

Stephen

I think that the pistons in the upper picture are 160 hp pistons. Are you sure those are 69S 180 hp pistons?

Richard

[Flieger]

Chromal cylinder bores from a 547 Fuhrmann 4-cam Carrera 4 cylinder motor.

[demo]

Here is what I am sure of. I owned the 69S, delivered to Brumos. I had letter from deceased owner stating rebuild at 55,000 miles. For no reason, other than he thought it would be a good idea before storing in early 80's. I had receipts for rebuild, and the box of P&C that were removed. The 69S is in Germany now, with 68,000 original miles.
I don't want to get too deep into this thread, because many times they end up in bickering. I have the answer to my satisfaction, no matter if some may differ. I am sure these are stock 2.0S cylinders. The pistons are shown on page 140 of Bruce Anderson's 911 Performance book. It clearly shows the 911S piston, and the 906 piston. Mine are like the 906 piston, which was definately higher compression than a stock S. The part number in piston also confirms this. Why the factory would use same piston in street S & race 906 makes no sense. So to my satisfaction, they are 906. After I get them bead blasted, I will try to determine a value, and offer them for sale.
Thanks for the info to this point.

Stephen www.route30classics.com