Aluminum base gaskets should only be used on the cylinders with a series of concentric rings cut into the cylinder gasket surface (o.1 mm deep at a distance of 2 mm).

If the cylinder gasket surface is smooth, it's recommended to use paper cylinder base gaskets.

The 1.0 mm aluminum gasket is only used when one wants to lower the compression ratio.

Aluminum gaskets were used commencing with following VIN numbers:

636 105 - R50/2
626 681 - R60/2
658 929 - R69S