> I would not do ceramic. Too risky. If it comes off say
        > goodbye to your expensive rotor housings.
        >
        > Paul Lamar

       Too true any filling is risky, remember this is cast iron -
   welding is
       difficult, although not impossible - would I trust it !?
       George ( down under)

   The rotors are made from grey castiron. A good welder should know
   how to
   weld them. then you need to machine them with a CNC and balance them ar
   around 12k rpm. The balancing can be done a turbo rebuild workshop as
   them balance teh shafts at 20k then at 140k (the Mazda Hitachi ones).
   It is important that you use a ceramic coating in the faces, due to
   heat.

   Roderick Scotto

   Do not use ceramic coatings. First it is not worth it. No improvement.
   And second I have seen it come off and destroy the rotor housings.

   Paul Lamar ...No rotor no motor.


paul,
ceramic coating like titanium nitride is just 5 micros thick.. I cannot
understand how it can destroy the housings

regards
roderick

Neither can I. I don't know what ceramic was used or how
thick it was.

As far as I know there are only two ways to transfer heat.
Conduction and radiation. If it is only 5 micros thick
how can it insulate effectively by conduction?

It is certainly is not shiny enough to reduce radiation
heat transfer.

BTW if it was possible to reduce heat transfer to the rotor
Mazda would have done it years ago as that implies a better
BSFC. Mazda engineers would sell their first born's for
a .01 better BSFC. Mazda engineers are by no means dumb.