930 Piston Pin Offset

[Steve Hummel]

I received a 930 engine in pieces ready for re-assembly. The pistons are stock, there are no valve reliefs, and it is apparent to me that the pins are offset. I have not built a Porsche engine before so I want to get it right. Each of the pistons are stamped with a '2', I think indicating the factory sizing.

My question is with respect to installing the pistons on the rods. Since the pins are offset and there are no other marks to indicate which way the offset goes would you be able to tell me how to assemble the pistons on the rods so that the correct offset is accomplished.

Thanks,

Steve

[David]

Since nobody's chimed in, I will. I didn't notice any offset in my piston pins although my pistons are at EBS right now. Can you post a pic to show the offset?

[Steve Hummel]

I notice that the pin offset is about 2mm measured with a set of dial calipers from inside the pin bore to the outside of the piston skirt.

Steve

[David]

I won't get my piston's back for another couple of weeks so I can't check. You might try posting to the turbo911 site and see if they know.

[Steve Hummel]

Found my answer. I have assembled lots of North American engines with pin offset, wanted to be sure that the Porsche was the same. I hunted down an old Porsche mechanic and he backed up the following link:

http://www.area.org/Members/EngineTech/edge1197/betts_advice_htm


Steve

[tab tanner]

If you look at the top of the piston you will see a zig-zag line, it will be near the edge just above the wrist pin. This goes to the flywheel end of the engine