Cylinder gaskets download
BSA M20 cylinder head gasket.pdf BSA M20 cylinder base gasket.pdf
BSA M20 cylinder head gasket.dxf BSA M20 cylinder base gasket.dxf
The .pdf files are just drawings while the .dxf files provide the electronic information for computerised cutting.
Notes on Copper Cylinder Gaskets

Computerised waterjet cutting machines require electronic profile information. The most common method to provide this information is via a DXF file.

Two DXF files are provided, one for a head gasket and one for an optional base gasket. The PDF files are a printout of the profile for information.

The DXF files need to be downloaded and emailed to service providers who offer water jet cutting.

In addition to the DXF files, you need to specify quantity, material (copper) and thickness. Thickness can be anything from 0.5mm to 1.5mm and can be varied to adjust compression height. Correct compression height should be set to give about 0.040” clearance between top of piston and cylinder head (with gaskets fitted).

You may be asking “why a copper base gasket?” When new liners are fitted, the top of the cylinder may be skimmed. Also when crank cases from 2 different engines are used, the cylinder base may be skimmed. This machining changes the compression height. This may of course be fixed by fitting a thick head gasket, but it is also good to have a solid, relatively incompressible base gasket. 

Copper gaskets are re-useable but need annealing before use. Annealing is done by heating to cherry red and quenching. This may be done in sections so the whole gasket does not have to be heated at the same time.

Peter Vlietstra
September 2013/ Update November 2018