In working through issues on my 1973.5 CIS 911, I see that there were some developments in connection with the gas lines, and the cold start valve.
In particular, the hose from the distributor to the cold start valve was a rubber hose for a 73.5 and 74 to some point. The CSV had a hose connector for the early ones, then a banjo fitting for the later ones - and the rubber line was changed to plastic. Seeing as how gas fires from rubber hoses that break is a big danger for 911s, and that the factory improved this, is there any reason to do this or not do this for my 73? I have all the parts to do it.
I note there were three ways the factory did this. On my 73.5, the CSV hose had its own port.
Sometime around 1974, there was still a rubber hose and the same CSV, but no longer a port. So it had a special banjo fitting with two ports, one for the inlet, one for the CSV (these are not pictures of my car)
Sometime after that, the rubber hose from the plastic gas line to the cold start valve was changed to a polyamide hard plastic tube. And the CSV was changed to a banjo fitting.
One thing I also noticed is that in 1974, Porsche added a flange to the CSV. At first the flange was just that, and the port off of it was blocked off. But then in later years, that port is actually used. I wonder if there is a reason to add that at this time too. If there is any benefit to getting the CSV to not be as deep into the air box.
https://www.youtube.com/watch?v=Nc-lJjwmovQ
Anyone have any thoughts on making the CSV hose into a pipe, and whether the CSV flange is valuable?