Hi there!


I´m just wondering why there are different materials for engine head shims.
My O.S. came with a 0,1mm copper shim and a 0,2mm brass shim.
My Nova got an aluminium one.
Why different materials?
I assume the copper shim is meant to go directly on top of the sleeve because copper seals very well. But why aluminium and brass?

Many thanks in advance!