It suppossedly is bad for the ceramic coating, presumeably because nothing's really dialed in yet, and you're kind of flogging the motor a bit. I think it's the danger of running lean and heating the headers to a bright glowing red.

I was unaware that you weren't suppossed to do it, when I ran my cam in a few years ago. I ran the cam in with my ceramic coated headers and nothing bad happened.

 

I've heard from others at the local car shows that it can cause them to discolor. I saw a set of silver ceramic Headmans that were on during cam break-in and they looked fine.

 

I have never seen a pair of quality coated ceramic headers discolor. Nickel plated is a different story.

 

From what i hear, your header warantee is void if you break in a cam with them, because of the reasons mentioned above (glowing headers = bad for coatings).

 

My exhaust header was Jet-Hot coated. I believe that is ceramic coating. I installed a two barrel carburetor after the header was on and had to tune the carburetor. The headers were never glowing red but it did cause the coating to fail, leaving it open for rust...which it did:

http://pic6.picturetrail.com/VOL174/2016453/3903966/94095764.jpg

Jet-Hot gives a three year warranty for the coating. I do not understand how I am supposed to tune the carburetor without damaging the coating, as I said, the header was never red hot. I still must pay for shipping both ways which is about $25.00, if I return it to get it recoated.

 

The rest of the header is not as bad:

http://pic6.picturetrail.com/VOL174/2016453/3903966/94096240.jpg

 

I did the same thing with the 390 and my Jet Hot-coated headers. No problem at all with the coating.

 

I asked Stan at FPA the same question, and he said that running too lean could damage the coating. He suggested adjusting the carb to keep it from running lean, and having 2 box fans pointed down at the headers to help keep the temperature down when doing the cam break in.

 

correctomundo! running lean is the #1 cause for ceramic header coating discoloration. the 'shiny' coatings usually have aluminum in them, which deteriorates at or around 1300 degrees far surface temperature. if your header is ever glowing red from running lean/hot for extended lengths of time(watch supercharger cars on a dyno) it WILL discolor the coating.

 

ok, why do you have a hose clamp on your headers? ::