Porsche Enthusiasts Club Forum

The other day I needed to replace the auto gearbox sump gasket on my '84 S2, since Porsche now regard the price list as confidential I rang my OPC £22 would buy a nice new one, two days delivery from Germany. I was about to say yes please when a thought occurred. The gear box internals are Mercedes made, examination of the gasket revealed a mounded in part number and the three pointed star. I rand my local Merc parts people, who had it on the shelf for £12. Now our cars are getting on, and we are going to need parts more and more. I wonder how much the disparity in price is common through Porsche parts? How does one justify the difference? Operational inefficiency? Or plain greed? A desire to maintain exclusivity?
Well I wondered what could be done to ease this situation.
Quite a lot of components are common to other vehicles and makes, the various specialist suppliers tap into this and hence are able to offer sensible prices.
Could we compile an index or cross reference table of part number and alternatives. There are thousands of parts, so if we were do some thing it would have to some sort of voluntary input, you've found a source of a part and enter the details into the data base for all of us?
What do folk think, and does any one IT savvy enough know how it could be done.

An aside, a friend of mine runs a 1965 TR4 and the first few pages of the parts list are a cross reference index of what other Triumph cars the parts were used on. In its time this must have been very useful, though now a lot of the other models are even rarer than the TR. Some thing similar would be very useful..

You raise an important issue on parts prices - and how to minimise them - and of course it's not unique to Porsche. While the SAAB brand still lived (under GM) I could obtain many identical parts for same platform car from Vauxhall for 1/3 the price!

Porsche themselves freely publish third party part numbers in the WSM - with whole tables and pages devoted to this in sections where parts are likely to be shared (ignition and injection especially). A lot of these parts are Bosch, and Bosch themselves publish cross-referenced application guides. So you can look up say the ignition amp for a 928 S4, and find it's also supplied in certain Citroens say. You can then look for decent aftermarket version of the Citroen part for even more saving.

Or using Porsche's own part number data, you can just google say the Bosch part number for the TPS, and find it's also used in certain BMW models. Again an eBay search on the BMW part usually results in saving, as people can't ask the Porsche 'premium'. Knock sensors are far cheaper bought this way.

Porsche's own parts catalogue can be searched to show you every Porsche model using a particular Porsche part number and again I find this very handy. You can find a part shared with a 993 say (I'm thinking of some brake pad dampers I had to source recently), and it's easier to find one for sale as there are just more of those cars around. Ditto 944.

So in theory a great idea to create x-ref but a lot of work! It's possible to get same result with just a few tools:

928 WSM
Porsche PET
Bosch cross-reference document
Google

PS there are also some parts which are almost identical but require a little work to make them compatible. Best examples probably the cooling fans for S4 that are same as part used on Cavalier, but you have to modify the connector!

There was a time when late S4/GTS rear wheel liners were NLA from Porsche, and someone discovered the liners from Peugeot 505 or 605 were a good alternative.

Interior lights compatible with Passat, but again connectors need modifying to match 928 loom.

Oh and of course the entire gearbox for which you bought the sump gasket (at the time, Porsche weren't used to designing auto boxes to handle 300+ BHP, so got the whole thing in a crate from their Stuttgart neighbours.

Oh on your original theme of identical x-ref parts, the window motors used in 928 also used for same application in Saab - you just need to research specific models.

Heater valve.., same as Mercedes 190 models ( I know)