Bilstien insert into Boge housing problem

[Racerbill56]

I am replacng some worn out Koni strut inserts on my vintage racing '67 912 and decided to change out to Bilstien inserts. When I opened the box I immediately noticed that they didn't seem to match the older Konis. The Konis were inside the strut housing and held in place by a hex cap nut with a hole in the center that had fairly fine threads. The new inserts have a metal threaded piece that is smaller in diameter than the threads on the housing and also a coarser thread. I went back and double checked to make sure I ordered the right part number and they indeed are supposed to be for '65-68 911/912 which came originally with boge inserts.

What am I missing? (The instructions that came in the box are virtually useless!)

Could you illustrate your question with some pics? It makes answering a lot easier. I replaced something like "Mulholland" in my '65/'66 by new Koni's. The thread at the top was indeed courser. I inserted them and used the old cap nut.

Otto

[Racerbill56]

The first photo is the Koni insert with the hex nut on top (made out of sheetmetal) and the second is the Bilstien insert sitting inside the housing and shows the difference in diameter and thread size.

[Rick Becker]

I replaced Boges on my 1966 912 with Bilsteins, shock designation P-111 front and B46-176 rear at the time. You may want to check if those shocks are still available, or superseded by another Bilstein model that fits. The cap nut supplied with the Bilsteins at that time worked perfectly on a Boge strut.

[Racerbill56]

I am assuming that the struts were originally Boge, does the gland nut in the photo look like one for a Boge equipped car or was it possibly a Koni-equipped car? This is my only early Porsche and I have never had them apart before. Maybe I ordered the wrong part...

It is indeed a Boge strut. The equivalent Koni insert has #86-1394 and Bilstein #P36-111.

The cap nut is reused for the new insert.

I hope this helps.

Otto

[Racerbill56]

After digging around on the internet, I came to the same conclusion. The only problem is that I have to heavily modify the cap nut (make the hole larger) to allow the larger Bilstein strut to poke through. I found a cheap set of KYB struts that come with both the large and smaller cap nut, so I bought them and will play with the new nut so I can always go back to a standard size again.

You would think that Bilstein would recognize that the early cars need a larger cap nut and supply both size of threaded collars (given the cost of the Bilsteins). Oh well, live and learn.