> 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 destory the rotor housings.

Paul Lamar ...No rotor no motor.

Paul has a MAJOR point here - there are a lot new coatings and many
unsubstantiated claims,
There is little if any data on wear/reliability.

Paul, can you name the coating manufacturer and under what conditions
they failed?
The rotor is for the most part a non-wear surface.  Some companies are
claiming
large oil temperature drops in service.

As a rough guess it would not take a very thick coating (say .020) on
the rotor face to raise
the compression ratio half a point.
654cc/10 compression ratio=65cc compressed, rotor face
=~7"*3.15"=22in^2=~142cm^2*.02=~3cc
654/65-3=654/62=~10.5.

Cheers
Cary

I saw the housing and rotors at Dave Leonard's house. I think
he was too embarrassed to tell me or he was  afraid of being
sued or he was trying to protect someone's reputation :)
Or he may have told me and I forgot.

With some research on old messages I might be able to
figure it out based on when he could have built that engine
or bought that engine. I warned people about coatings
a long time ago.

The junked housings looked and felt like medium sandpaper.

I suspect a rotor could benefit from chrome plating
if one could be sure it did not come off. A lot of heat
transfer to the rotor is caused by radiation. 3,000 degree
F combustion is white hot.

Paul Lamar ...No rotor no motor.

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