Early and late camshaft o-ring seals

As specified in Technical Bulletin TB 78-03, a change occurred in 1979 when an o-ring groove was removed from the camshaft and added to the camshaft sleeve bearing. A larger o-ring was required. 

Specified in TB 78-03:

  • Early o-ring P/N 99970145240, size 18.4 X 2.4mm
  • Late o-ring P/N 99970159240, size 23 X 2mm

NOT specified, an additional change occurred to the cam carrier housings when an o-ring groove size increased.  A larger o-ring was required, however this was not documented.

  • Early o-ring P/N 99970142540, size 52 X 4mm
  • Late o-ring P/N 99970160240, size 50 X 5mm

The TB reads from following engine numbers: 8280082 (manual) and 8289026 (auto).  Physically check your 928 before ordering parts. While performing this service, I recommend that you replace the following parts as well:

  • Camshaft seal P/N 99911328240
  • Oil galley seal P/N 92810518400
  • Distributor seal P/N 92860210300

Quantity 2 each Use assembly lube on all o-ring seals
Important: Set engine timing to TDC before removing the distributor.

camshaft oring seals porsche 928 technical bulletin 7803
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