A little stuck on a which pipes SS or mild. How have your mild steel headers held up?

[ng8264723]

I have heard that SS work harden and crack overtime. The mild steel headers don't share this problem but of course they rust. How have the Kirkham's with mild steel headers held up? Any rusting out. Kirkham's have been around a while now so we should be able to see

[trs900]

I would recommend ceramic coating what ever you get unless looks are not important, I see some here wrap with tape to keep heat down anyhow so maybe it wouldn't matter, here in Florida everything seems to rust including stainless steel over a period of time, I guess there are several different qualities.

[Murphy]

I considered SS but know harsh vibrations can make it crack and SS transmits heat at a higher rate than mild steel. Heat was my main concern.

[Dwight]

I have mild steel ceramic coated headers and side pipes. They cool a lot quicker (to the touch) than other pipes. They advertise that the ceramic coated pipes hold the heat inside so that it can be blow out the end of the pipe. Hype or fact? I do know they cool to the touch a lot faster than others. I like them better than chrome, paint, etc.

Dwight

[xlr8or]

I have the steel and no problems yet.

[Bobcat]

On stainless steels , there are many different grades , all with different resistance to corrosion and hardness/strengths. As a general rule , the lower the number ( 316 SS for example , compared to 416 SS ) , the better the corrosion resistance , but 416 is a stronger steel . 17 -4 ph stainless is a strong stainless that approaches "regular " steel in strength , but is not as good as 316 on corrosion . We used the 17 - 4 ph on hydraulic cylinder rods in the offshore area as we need strength and some corrosion resistance .
One thing you have to be careful of is to not clean any stainless with a wire brush or anything like that as you will deposit the mild steel on the stainless , which will then rust .

[ng8264723]

I figure Kirkham would use 304. 304 always looks good. It's what the Borla stuff is made of. I'ver had a few Borla systems they last forever and never tarnish and don't need coating. They were cat back systems on daily drivers. Even my truck through NY and Ma winters still looked good. Headers are a different story closer to the engine and hotter
chris

[ng8264723]

I decided to email Joe to get mor info about the ss headers. Do the Kirkham mild steel headers come coated? Or is the price on the price sheet for bare steel?

[xlr8or]

Bare steel.

[ng8264723]

Wow! There is only a $1000 difference. What does it cost to get the headers side pipes coated
chris

[Tom Kirkham]

We use 304 Stainless Steel.
The mild steel headers are bare.
For a good tech article on stainless headers see:
Stainless_article

[ng8264723]

Tom,
I read the article definately worth the read. Unfortunately, there isn't much mention of the work hardeneing and fatigue I've heard about with headers. I heard from my machinist that the boat headers that are made os ss ork harden and when they crack are not amendable to welding. I wonder if this is true?

[David Kirkham]

Murphy,

Stainless steel (304) transmits heat at about 1/3 the rate of mild steel. That is really one of the big reasons we use it. But, there are other reasons.

If you wrap normal, mild steel headers with an insulation, the heat in the pipes will rise dramatically. The higher the temperature, the faster the rate of chemical reactions--like rust. In many biological instances a mere increase of 10 degrees will double the rate of a reaction. Rust is not only caused by water, but is exacerbated by several substances, like salt for instance. The by products of combustion are particularly nasty in their corrosive effects--especially at exhaust temperatures which are around 1200 degrees. That is the reason why so many of you have seen the inside of headers "rotted out" while the outside seems perfectly normal.

I have yet to see a set of our stainless steel headers crack. I would be very surprised if they did as stainless is specifically used in these high temperature situations to resist such problems. Today, most every car on the market has stainless exhaust to comply with the Federal Emission rules that a car must pass emissions for 100,000 miles with no failures. Even with the less than optimal alloys the automotive industry uses (they'd sell their mother to save a penny on material costs) fatigue is not a problem with a stainless exhaust system. In fact, it is the material of choice for our vehicles.

David

[RodKnock]

ng8264723, be aware that the Kirkham SS sidepipes have a different appearance than the standard mild steel sidepipes.

[David Kirkham]

Originally Posted by ng8264723

Tom,
I read the article definitely worth the read. Unfortunately, there isn't much mention of the work hardening and fatigue I've heard about with headers. I heard from my machinist that the boat headers that are made os ss ork harden and when they crack are not amendable to welding. I wonder if this is true?

I have never known work hardening to change weldability. In fact, to eliminate work hardening, you heat a metal up to anneal it or to normalize it. But, REMEMBER, work hardening or (cold working) a metal is NOT the same thing as heat treating/PH/tempering a metal.

David

[ng8264723]

David,
Could you post a pic of both the ss system and the original type? How much different are they? Everyone says they don't look original. I would like to see how far off they are. What was the reasoning for changing the design? The cars have been around a while have the mild steel headers had rust issues on the older cars

[ng8264723]

David,
By the way in bio the main change in rate of reaction is due to enzymes:
Enzymes can act rapidly, as in the case of carbonic anhydrase , which causes the chemicals to react 107 times faster than without the enzyme present.
Temperature has an influence but only to a point. Enzymes actually function at only certain temps. If the temp then the reaction rates drop. Ever wonder why bees move slowly when it's cold in the am? As temp increase reaction rates rise dramatically until 40 C I think. Or thereabouts at that point the enzymes (which are protein) denature and the reaction rates decrease. Chemical reactions without the influence of an enzyme catalyst increase 2-3 fold for every 10 degress increase in temp. In bio if our core increased 10 degrees we would be in the ICu if we made it there. What keeps animals at the desired temp? Homeostatis. That's another topic altogethere.
chris
PS The MD helps with these discussions

[alpace@pacificp]

Recently received my Kirkham. I went up to Provo and spoke with Joe about SS vs. Mild Steel. As another member noted, historically the SS pipes looked different from the mild steel...withthe mild steel looking a bit more traditional/true to form while the SS had a bit of the 'motorcycle muffler' look going.

Anyway, Kirkham recently had some new pipes made out of SS, but with a turer to form 'bullet shape. Bottom line, they are SS, look GREAT and sound great. Had them painted black.

al

[Murphy]

David, I read the article you posted. Clears up the myth I believed that others wrote about heat transmission and stainless. With that said, why did you let me buy the steel pipes? PS how are those KMS emblems coming along?

[RodKnock]

Originally Posted by alpace@pacificp

Anyway, Kirkham recently had some new pipes made out of SS, but with a turer to form 'bullet shape. Bottom line, they are SS, look GREAT and sound great. Had them painted black.al

Hey Al, did you have the stainless steel painted black?