Headers...Paint or Leave As-Is?

[OK-944]

Purchased a rattle-can of VHT "Flame-Proof" aluminum color ceramic header paint yesterday...but after polishing up my headers with a nyloc wheel, I kind of like the way they look as-is.

But...would there be any advantage to painting the headers? The text on the can mentions that when painted the headers will give off less heat - and that the engine will somehow deliver more power.

Sounds like snake oil to me, although it would be nice to have a bit less heat in the engine-bay. Then again...might this stress the rest of the exhaust system in some way?

[jjeffries]

Since you were able to polish your headers, I’m assuming these are the tubular version? My car, with its original and seized motor, had those, but my for my replacement engine, HondaDustR selected the earlier cast version. Accumulated wisdom seems to suggest that the tubular version yield a tad more power (correct? wiser men please comment) but can be more fragile than the cast versions.

As to durability of that product, I have no wisdom or experience to contribute. Statement of the Obvious: preparation will be everything.

Best, John

[Wellwood]

Thermal effects from the headers being coated depends on two factors-

The amount of material sprayed onto the headers - and the color.

The material may have a slight insulating value (ie, impact on thermal conductivity which impedes heat transfer to the surrounding area), thereby trapping more of the heat from the exhaust gases. To be honest, only ceramic coatings probably aid in this area.

Color on the other hand does play a significant part on radiation heat transfer. The darker the color, the more heat will be emitted from the exhaust headers. Ideally, a bright shiny surface will be the least to emit heat. Think about it like this - silver teapots are nice to look at, but they are shiny because they don't radiate heat very well. Black objects on the other hand emit heat best.

[thomasryan]

half convection and half radiation. black absorbs more and gives off more radiation

i would ceramic coat the exterior just so it it has a better chance of staying clean

[Stoneguy]

I too had to replace my headers. My 86 came with the tubular type and I had trouble with the notorious 1-4 cracking at the welds due to expansion/ contraction during heat cycles.
After searching for a , non cracked, replacement, I had no luck.
I ended up getting a set of Billy Boat stainless steel headers.
They have a slip fit joint at the #1 pipe to compensate for the thermal expansion. I left them uncoated and they have transformed to a pleasant shadeof bluing.

[v2rocket_aka944]

99% marketing BS, but they will look great.
there are coatings that will keep heat in the pipes better and can help produce more power, but they don't come in an $8 spray can.

[Ernie944]

Originally Posted by v2rocket_aka944

99% marketing BS, but they will look great.
there are coatings that will keep heat in the pipes better and can help produce more power, but they don't come in an $8 spray can.

+_1 on that spray can is spray can LOL.

[Wellwood]

While convective heat transfer is present under the hood, I submit that with regards to the purposes of the coating as it relates to heat transfer, it is irrelevant.

[PHillary]

The coating will help with the heat...I had mines professionally ceramic coated for like $300 bucks...I believe this can also be achieved with a rattle can as well...It is ceramic coating in a can if you apply it nice and evenly I believe you will yield good results.