Ceramic Coating Discolouration

[09holden]

Hi all,

I have a set of 6mth old extractors that were ceramic coated and since a recent dyno tune the outside corners of the bends that come directly off the manifold have discoloured. It has gone a dull silver/pale yellow colour and doesn't feel as smooth as the normal coating.

Has anyone experienced this or is it likely to be a dodgy coating?

Cheers, Ben

[rumbles]

You see the same thing with stainless pipes, and it is pretty much at the hottest point so I'd expect a bit of severe baking. Different ceramic coatings cook at different temperatures as well.

[09holden]

Thanks! Should i be concerned about it or be contacting the company? Is it likely the could begin to rust at these points?

I scratched it a bit and left a little mark where as on a normal section it did nothing!

[macca33]

Normal - the coating does wear out, as with anything. The extractors get VERY hot and then cold over many, many cycles. Nothing is infallible.

That said, if they are only fairly new, you may be justified in making some inquiries.

cheers

[rumbles]

There's another point too; stainless is not as good a heat conductor as mild steel - it concentrates the heat rather than letting it disperse throughout the pipe. So it will be considerably hotter at the source compared to a few inches down the pipe. I've seen ceramic coat on stainless do what you've described, at the manifold and on the sharper bends as the flow is reduced and the heat builds up there.

[Benton]

Try giving those spots a polish with Brasso, works a treat on with any stains sustained by the headers when in contact with something dirty eg. oil or grease marks.