Chain rail trivia question
 

Has anyone here ever seen smooth top chain rails in an engine that has never been taken apart before? All six chain rails are smooth. One more thing to note; they are all the same height as the short one that normally goes in the right, lower inside of the block. (911 105 222 05)
The car is a 1976 911 Turbo with approximately 30k original miles.
Here are some pictures of it next to a new, short chain rail.
http://forums.pelicanparts.com/uploa...1130370544.jpg


http://forums.pelicanparts.com/uploa...1130370778.jpg

http://forums.pelicanparts.com/uploa...1130370804.jpg

NO ONE???? I thought for sure somebody here has seen these before.
Heres my thought; I think this was a prototype that Porsche was playing around with and only a very few cars actually had them. Maybe a test run for nylon before they came up with the grooved type???
The rubber chain rails sure didn't cut it!

Mercedes had some smooth ones. Maybe that's where yours came from.

I suppose that is possible. Although, as stated before, the eingine has never been apart till now. I have not seen a MBZ chain rail though so I couldn't say for sure.

Who knows? Maybe the guys from Mercedes came over to the Porsche factory to learn how to build good motors. The Mercedes motors from the late 70s were dogs, IMHO.