cam housing 901.105.111.0R--what year?

[911SCfanatic]

Trying to figure out what mish-mash of parts I have on this engine. The case is a 73.5 2.4 7R case, but I have the MFI from the original 72 (based upon the MFI pump #). I'm trying to figure out where the 72 ends and the 73.5 begins. What year is a 901.105.111.0R cam housing from?

Also, if you wouldn't mind, what are the part #s for the heads and cylinders for 72 and 73.5 (CIS). I looked in Wayne's book, but it only goes back to 74.

Thanks.

[Jubbie]

You may be getting mixed up in the Porsche casting number never changing trick.

On my 930/02 engine, I had one cam tower with a 901. number and the other was a 930. number. But, both were 4 bearing cam towers. I also had two fan shrouds with the same casting number, but they were different where the alternator tied in.

On the cam towers, the way I understand it, it is either a 3 bearing or a 4 bearing tower. That is all the difference there is.

[sammyg2]

Yup, just looked and the casting nubers on my 1980 SC match those same numbers, so it looks like they didn't update them to match part numbers.

[Wayne 962]

There's basically the three bearing towers, and the four bearing towers. Only minor changes other than that...

-Wayne

[911SCfanatic]

Thanks guys--very helpful. There's a lot to learn in Porsche forensics.

So if I understand correctly, the numbers ending in "R" are casting numbers that may be common accross many years. I'm assuming that any significant revisions in the casting would result in a new, higher number casting number. For example, the mag cases going from "5R" to "7R" toward the end of their production.

Is there some source that references the casting numbers for engine components? Is there some relationship between the casting number and part number? The only reason I care is that the engine appears to be a conglomeration of 72 and 73.5 parts and I'd like to figure out the source of the parts.

[jluetjen]

Is there some relationship between the casting number and part number?

Yes -- it's known as a "One to many" relationship in database terms. One casting number may be used in multiple part numbers.