Coating for Headers

[CGOffroad]

What does anyone use to coat header / collector? In the past I have sent headers to a powder coat company that had ovens and did 'baked on'. But, i am considering to try an air dry product.

https://www.cerakote.com/shop/cerako...C-111/tungsten

Does anyone have experience with this? Have an opinion? Suggestions?

[Rick Iverson]

What does anyone use to coat header / collector? In the past I have sent headers to a powder coat company that had ovens and did 'baked on'. But, i am considering to try an air dry product.

https://www.cerakote.com/shop/cerako...C-111/tungsten

Does anyone have experience with this? Have an opinion? Suggestions?

Gray:

I do not think it will cut it.

https://www.apexspeed.com/forums/sho...er+temperature

[stonebridge20]

What does anyone use to coat header / collector? In the past I have sent headers to a powder coat company that had ovens and did 'baked on'. But, i am considering to try an air dry product.

https://www.cerakote.com/shop/cerako...C-111/tungsten

Does anyone have experience with this? Have an opinion? Suggestions?

This is absolutely a good choice. We did a set of S2 and a set of GT1 headers a few years ago and they still look like new.

[Bobsy SR 6]

Gray

3 years ago I built a set of headers, coated them with Eastwood spray on ceramic coating for headers. They still look like the day I coated them. Eastwood also has a an extended tip kit to allow you to coat the inside of the tubes as well. I removed the header last year ( for other maintenance issues) and the inside had very little carbon and the ceramic coating looked perfect. Prior to coating the header I bead blasted it promote adhesion and for a nice clean surface. Way cheaper then jet hot or similar processes.

Best
Tom

[S Lathrop]

Years ago before we had all these new coating materials, there was a common practice that worked very well. Call it "red Neck" coating. We used transmission oil from gear changes to build a very good coating on the headers This was when headers were mostly mild steel, before stainless steel became common. We would wipe the header system down after each gear change. Yes the headers smoked but after couple coatings and heat cycles, you had a good coating that inhibited rusting of the headers.

One issue with a lot of header coatings is that they increase the heat of the header by reducing the ability of the header to dissipate heat from the header.

[Jerry Kehoe]

Over the years I have found that taking new headers and torching them and coating with automatic trans fluid then simply spraying with WD40 after you are done with the weekend worked well, was cheap, made any repairs for cracks, etc easy and looks great. Ceramic coatings look great when fresh but if you need to repair anything you have to grind off the coating then you are stuck with an ugly mess unless they are redone.

[veeten]

I have had good luck with Eastwood coating also . Used it on Air Cooled 2 & 4 Stroke engines and Flathead Marine engine.
Not as good results on Big Block RV Engine.

[10rmotor]

One issue with a lot of header coatings is that they increase the heat of the header by reducing the ability of the header to dissipate heat from the header.

Thats what you want, to keep the heat inside the tube, not radiate it out to the surrounding components that probably don't like to be hot. it keeps the heat energy inside the headers which promotes scavenging and Hp. Most people coat them for the corrosion resistance and because it looks cool. Stainless headers definitely help in keeping the heat in compared to mild steel so coating them is less beneficial.

[S Lathrop]

Thats what you want, to keep the heat inside the tube, not radiate it out to the surrounding components that probably don't like to be hot. it keeps the heat energy inside the headers which promotes scavenging and Hp. Most people coat them for the corrosion resistance and because it looks cool. Stainless headers definitely help in keeping the heat in compared to mild steel so coating them is less beneficial.

I should have added that what you don't want is for the header tube to be over heated. The high heat will deteriorate the tube. The best idea would be to coat the inside of the tube.

I found out the hard way that coating the out side of a header is a prescription for failure of the header right at the exhaust port. The exhaust gasses are close to the melting point of the headers. You want to dissipate that heat as soon as possible. I have had headers fail in a race or two when they were coated. That was common for mild steel headers. Stainless will hold up better but you are risking header failure by coating a stainless header just as you are with a mild steel header.

Bottom line, don't coat or wrap the outside of exhaust headers.

[10rmotor]

I should have added that what you don't want is for the header tube to be over heated. The high heat will deteriorate the tube. The best idea would be to coat the inside of the tube.

I found out the hard way that coating the out side of a header is a prescription for failure of the header right at the exhaust port. The exhaust gasses are close to the melting point of the headers. You want to dissipate that heat as soon as possible. I have had headers fail in a race or two when they were coated. That was common for mild steel headers. Stainless will hold up better but you are risking header failure by coating a stainless header just as you are with a mild steel header.

Bottom line, don't coat or wrap the outside of exhaust headers.

Totally agree Steve. I too have seen most primary tube failures right at the exhaust port. If you have heat sensitive components near the headers by all means wrap or coat them but otherwise, leave them alone. Stainless especially. I sometimes am able to use the stock titanium headers (kawi and suzi bike motors) as a base for car headers, and see absolutely zero reason to wrap or paint those!

[BeerBudgetRacing]

So ceramic coat the inside?

If that will reduce temps of the header tubes then maybe typical exhaust paint that will allow heat dissipation might survive the 'reduced' temps....

[B Reid]

I have used this in the past with good results. They do coat the inside of the tubes at the header flange as well.

https://swaintech.com/race-coatings/...aust-coatings/

[DaveW]

A little off-topic, but for my SS Zetec headers I've concentrated on heat shielding plus cooling air flow, aided by my air exit tunnel. I am reluctant to decrease the ID of the 1.5" header tubes by 0.03" (ID by ~2%, tube cross-section, i.e., flow, area by ~4%) to apply a ceramic coating to their inside. And like Steve, I think coating only the outside compromises the life of the header.

[BeerBudgetRacing]

A little off-topic, but for my SS Zetec headers I've concentrated on heat shielding plus cooling air flow, aided by my air exit tunnel. I am reluctant to decrease the ID of the 1.5" header tubes by 0.03" (ID by 2%, area by 4%) to apply a ceramic coating to their inside. And like Steve, I think coating only the outside compromises the life of the header.

I get the point but I believe the area loss is also 2% given all other factors (pi and length) are fixed.

Do we know if the optimal tube size is really 1.5" ? Maybe 1.4 ?

For me it's all about making things last. People coat piston tops to reduce heat transfer, etc.
If I can send the heat down the pipe that keeps the engine bay cooler and reduces stress on other components as well with out having to increase cooling in the engine bay. Cooling is drag, right?

So I get the point about not coating the outside for sure.

[EYERACE]

Cheap? ......Hmmmm...... Now or Later

Any exhaust header I get will go to Jet Hot for their Ultra Extreme 2500. Cheap? .....does it really matter?

[DaveW]

I get the point but I believe the area loss is also 2% given all other factors (pi and length) are fixed...

Tube cross-section area is proportional to diameter (or radius) squared...

[BeerBudgetRacing]

Area is proportional to diameter (or radius) squared...

No, you have to introduce a length or height. Your basically unwrapping a rectangle. one dimension being circumference, the other being the length of pipe section. It's not the area of a circle.

1.50 x 3.14 = (circumference) x height (say 1) = 4.710 in sq

1.47 x 3.14 = (circ) x height (1) = 4.616

(4.71-4.616) / 4.71 = .021

So the 'squaring' is constant.

I re-read and you are saying the area of a slice of pipe, but that is not what absorbs or dissipates the heat which is what we are talking about. The surface does (inside and out).

[DaveW]

No, you have to introduce a length or height. Your basically unwrapping a rectangle. one dimension being circumference, the other being the length of pipe section. It's not the area of a circle.

1.50 x 3.14 = (circumference) x height (say 1) = 4.710 in sq

1.47 x 3.14 = (circ) x height (1) = 4.616

(4.71-4.616) / 4.71 = .021

So the 'squaring' is constant.

I re-read and you are saying the area of a slice of pipe, but that is not what absorbs or dissipates the heat which is what we are talking about. The surface does (inside and out).

LOL - We're talking about 2 very different things.

A great example of what happens when one doesn't clearly define the context, and that's my fault.

You're talking about pipe surface area, which relates to heat dissipation and heat transfer out of the tubing. You're obviously correct in that calculation. I was talking about cross-sectional (flow) area of the exhaust tubes which relates to how much exhaust volume it can flow with a given back-pressure. I am reluctant to decrease the flow capacity or increase the back-pressure.

So we're both correct. I clarified my previous posts to clearly define what area I was referring to.

And, carrying this one step further, it would be the best of both worlds if one could reduce the surface area w/o reducing the cross-section area (i.e., reducing heat transfer w/o restricting flow), but a round tube already optimizes that ratio.

[BeerBudgetRacing]

Couple of interesting reads:

https://centuryperformance.com/tech-...stroy-headers/

https://centuryperformance.com/tech-...ng-and-length/

[Rick Iverson]

Cheap? ......Hmmmm...... Now or Later

Any exhaust header I get will go to Jet Hot for their Ultra Extreme 2500. Cheap? .....does it really matter?

Yes