Dear Vintage - Opel friends,
I'm pleased to be able to offer you the following article:
Stop screw plastic camshaft, Opel 4-cylinder & 6-cylinder cih engines
This plastic screw aligns the camschaft exactly with the cylinder head. Simply install at the front of the camshaft and prop it against the front camshaft cover. Suitable for all cih engines, this screw is susceptible to old-age breakages. Best to have a spare handy. Obviously this is an original Opel part.