Cylinder head alignment sleeve

[teknow]

Hi

I notice that many BMW's including the 5 series use locating dowel sleeves for ensuring the cylinder head and block align correctly.

The part number I found is 11-12-1-726-243

Does the head bolt pass through the sleeve ? Also these are referred to as 13.5mm diameter. Does anyone know if this is the internal or external diameter?

Reason for my questions is I think these are the same as my Porsche 924. The Porsche part is no longer available so I'm looking for a dowel sleeve that will allow a 12mm bolt to pass through it!

Your help would be greatly appreciated.