Timing chain cover

[Eric Straub <ericst@MICROSOFT.com>]

Hi Listers,

When I took my engine apart and cleaned/repainted the parts, I noticed that
the timing cover had some sort of clay like substance on the exterior (side
which faces the fan). In looking at the Bentley manual, I see the picture of
the timing cover also has this substance on it.

Does anyone know what this substance is, what it is for, and where to get
some?

Thanks,
 Eric.
Restoring '67 Mk 2 Spitfire