Hi,
Measurements done and this is what I found:
The conrod length center to center =128mm.
The Gordini piston gudgeon pin = 20mm. Standard 1108 =18mm
The Gordini piston deck height =39.5mm standard 1108 =37.5mm Not sure of this one as the sizes were taken from a 1400.
The piston bore of the Gordini =70mm standard 1108 =70mm.
the stroke of the Gordini =72mm standard = 72mm.
Remember that with the combination of standard bore and G pistons the rods must be 128mm. Any 1289 or 1300 the rods will be shorter to compensate for the longer stroke of 77mm.
So all these sizes doesn't help if we can't compare with stock 1108 or 1289 sizes to assist in building a engine for Stcos85.
These 2 photos is that of a 1100 Gordini piston. This is what the pistons should look like. Different to the 1255 ones.
This is what the conrods look like on this engine. Remember I said it had a hard life, so what I noticed is that it is different from what Simon said. These don't have bushes so I think they have been re-sized in the past.
To get back to solving the problem I am sure that if we can get a set of 1108 rods with its 18mm hole, it can be safely increased to the desired 20 mm of the pistons. There is even a chance that it can be machined with a slight offset to adjust piston heights in the case there is some discrepancies.
Please correct me if anyone sees a mistake but I think it is very possible to build a nice engine even if there isn't a 100% Gordini content.
Regards, Frans.