Educate me about ceramic coatings

[GH85Carrera]

In my upcoming engine swap for my beloved El Camino the one “while I am in there” project I plan do is replace the cast iron exhaust manifolds from the 305 with new shorty headers. Those old manifolds would strangle the new 350.

My question is about which headers should I get. On some of the other forums the opinion is that headers with a ceramic coating from the manufacturer is the lowest quality cheapest possible coating. The opinion is to buy quality headers that are uncoated and have a local company put on a good quality coating.

That seems counter intuitive to me. In my experience manufacturers can produce a better final product than a local company working with a product that was made by some other company. I have no experience with ceramic coating however so I am looking to the Pelican brain trust to shine the light of experience on the subject.

The engine is NOT going into a show car. It will continue to be my daily driver. The only reason I want ceramic headers to is make them last longer and look decent. I don’t want a rusty old cheap header that rots out in two years. I don’t want to spend 800 bucks on a stainless steel custom header either.

So bottom line question: Would you buys a set of headers with a factory ceramic coating or the uncoated headers and have a local shop coat them for you? Any other options?

[sammyg2]

What type of coating is it? Many times on exhausts they use an aluminium-oxide type of coating and call it ceramic.

We have boron-duffusion coating done to machine parts faily often for erosion resistance, it makes the parent metal very, very hard but the coating is only a few mils thick. I'd be interersted to see if they use the same process.

If it's the same as what I'm familiar with, basically they clean a part and put it in an oven and gradually take it up to a prescribed temperature, then introduce a hot vapor of a desired metal or substance and allow the hot vapors to permeate the object and stick at the molecular level and then they do a controlled cool down.
The prep, the time in vapor, the temperature controls, all affect the quality of the coating.

Damn, now I might have to do research today instead of watching Andy Griffith.

[BeyGon]

For my 455 Buick engine I used the stock exhaust, they are very good, like rams horn Corvette exhaust but better, had them ported and ceramic coated on the inside, not quite as good output as headers but quiet, people would pull up at a light and listen, couldn't hear headers and thought it woud be easy.

[Laneco]

Glen,

I've used HEDMAN headers on a couple of vehicles now. I used the shorties on an 87 G-body. I'm guessing you have a similar year Elky as you have a 305. Good fit and quality. I buy only the coated headers. The coating is thinner than the coating we have had applied locally but it does seem to do the job. Our local company who does this puts down a great deep layer. They've done ram horn manifolds for me as well. Definately worth considering if you have a good local coating shop.

The HEDMAN headers are available with a ball/socket at the collector end. I really like this for a street car as it seems to eliminate leaks. The other option (in my opinion) is straight flange with a bit of flex to join the headers to the under body exhaust system. Your car has a fair amount of chassis flex so a little fore thought in this area will save you some aggravation down the road.

For a DD, look into ram horn manifolds. Make sure they'll clear your steering, etc., but for a DD, they beat headers hands down. Especially ceramic coated.
angela

[willtel]

I have coated headers on my Bronco and they are holding up ok. I bought them from a Bronco parts vendor and they were already coated, they were pretty expensive for 302 headers.


IMG_5554 by willtel, on Flickr

[Mark Henry]

If the coated headers are cheap you know that the coating is also cheap. Prep is the key to a good job and can add to the cost. headers should be "manicured", welds should be ground smooth, all splatter removed and sharp edges rounded over. Without this the coating will be substandard at best.
Ask around car clubs in your area and see who they recommend.

[porsche4life]

Glen, check out these guys. We have had them do some powder coating and they do Excellent work. They aren't too far from you either....

Welcome to Performance Coating

[Zeke]

I have coated shorty's on a SBC that I bought "at market" out at the local semi monthly swap meet. No problems in 10 years.

[GH85Carrera]

Originally Posted by Laneco

Glen,

I've used HEDMAN headers on a couple of vehicles now. I used the shorties on an 87 G-body. I'm guessing you have a similar year Elky as you have a 305. Good fit and quality. I buy only the coated headers. The coating is thinner than the coating we have had applied locally but it does seem to do the job. Our local company who does this puts down a great deep layer. They've done ram horn manifolds for me as well. Definately worth considering if you have a good local coating shop.

The HEDMAN headers are available with a ball/socket at the collector end. I really like this for a street car as it seems to eliminate leaks. The other option (in my opinion) is straight flange with a bit of flex to join the headers to the under body exhaust system. Your car has a fair amount of chassis flex so a little fore thought in this area will save you some aggravation down the road.

For a DD, look into ram horn manifolds. Make sure they'll clear your steering, etc., but for a DD, they beat headers hands down. Especially ceramic coated.
angela

Thanks! I will look into ram horns. The one thing I dreaded was the noise of headers.

[BeyGon]

Get them ported and coated inside.

[RWebb]

ceramic exhaust ports are very worthwhile on high popo motors

for coated headers you have to compare the cost vs. what your are trying to achieve (no rust for 50 years?) - there is not much perf. gain there

[flipper35]

After having one of the big names in ceramic coating do my headers and side pipes only to have them start rusting within 6 months and having them recoated under warranty and having them start rusting again in 6 months then they told me they wouldn't be covered under warranty any more when I lived in the desert where they probably wouldn't have rusted if I had painted them I would think a factory coating would be a much better proposition and I think this is one of the longest run on sentences I have ever written.

[GH85Carrera]

That was a long sentence.

Good info. Thanks.

[Laneco]

Originally Posted by BeyGon

Get them ported and coated inside.

Oh, good point. The last set of rams horn manifolds I had were coated inside and out. While the engine was running you could actually hold your hand on the manifolds for a couple of seconds at a time. The reduction in under-hood temperature was very noticeable. I had them on a Jaguar XJ-6 with a 300 horse 350 under the bonnet. Even the hood of the car felt cooler - the differerence was really dramatic.

Another nice thing about the ram horns is that you can get them wtih flanges for accessory mounting (a/c, p/s). If you are using the headers, you've got to sqirrel a bit to fab up the mounts. Either spend dough for a custom setup or make one.


angela