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Cracking headers

Slonopotam

Slonopotam

NAXJA Member #1358
Location
San Jose
Hi,

In the 10 years that I have owned and 100,000 miles that I've driven on my '96 Cherokee, I cracked 2 headers. First was stock, I think, and the next one was APN. Come to think about it, I probably drove on cracked headers for most of those 10 years. The crack I saw this week while bleeding brakes made me afraid I might lose the s-pipe on a highway.
I am looking for something that would last at least 2-3 years. If it gives me a couple of extra ponies, I won't complain.

I am considering two choices:

1. Doug Thorley
http://www.completecherokee.com/prod-307.htm
$560

2. Banks Revolver
http://www.quadratec.com/products/17601_501_07.htm
$440

I am trying to understand how one would justify $120 price difference. I read somewhere Doug Thorley headers are ceramic coated. Does it make substantial difference?

Also, Banks has 5 years warranty and Thorley has a lifetime one.

Any other reasons to choose Thorley over Banks?
 
Besides poor construction techniques, bad motor mounts are one of the main causes of header failure.

I doubt there are any significant differences, I would suppose you are paying extra for a name or the CARB approval.
 
ceramic coating is simply powder coating with a special chemistry that required a high-temp heat cycle to complete the process so that the paint stays put at 1000 degree temps. Generally headers get a little too hot close to the heads and that causes the material do degrade. Paint doesn't prevent this. It's only color and some corrosion resistance. As mentioned above, proper mounting with regard to movement is your best solution.
 
Look into headers that have a section a flex pipe built in to it. There's a lot of heat shrinking/expending and twist on the length of an inline 6 that leads to the cracking too. Having the flex gives the header some give so it won't crack
 
Don't APN headers have a lifetime warranty? Another good suggestion is to cut your downpipe just in front of the tranny and install a section of stainless braided flex pipe. Like others have already stated worn motor mounts will cause any header to crack.
 
Hardkor said:
Another good suggestion is to cut your downpipe just in front of the tranny and install a section of stainless braided flex pipe.
Click to expand...

I have two of them to allow movement in all 3 dimensions. One of them in the location you suggested. I hope those flex pipes allow sufficient range of movement for motor mounts condition to not have a big effect.

I installed new motor mounts (brown dog??) some time ago. During installation I discovered that the unibody was not perfectly straight. Mounts did not look very well aligned. I was not sure what to do with it, so I just left it the way it was.
 
Hardkor said:
Don't APN headers have a lifetime warranty? Another good suggestion is to cut your downpipe just in front of the tranny and install a section of stainless braided flex pipe. Like others have already stated worn motor mounts will cause any header to crack.
Click to expand...

Good luck getting them to back that up.
 
I have owned my 98 (Oct 97) and installed MORE motor mounts in late 1999 after the factory mounts went bad.
In 2003 the factory header had several cracks and replaced with the Banks header. Since then I replaced the header in 2009 and 2015 due to cracking in junction of the tubes near the collector. The Banks header design has been changed several times over the years trying to resolve the problem of cracking. With that said.... that is the only thing bad I have to say about the Banks header.
They have also replaced the header each time under warranty....
 
ftwelder said:
ceramic coating is simply powder coating with a special chemistry that required a high-temp heat cycle to complete the process so that the paint stays put at 1000 degree temps. Generally headers get a little too hot close to the heads and that causes the material do degrade. Paint doesn't prevent this. It's only color and some corrosion resistance. As mentioned above, proper mounting with regard to movement is your best solution.
Click to expand...

I think someone done told you wrong, or a product that is not ceramic coating is being called ceramic coating.

I can tell you from first-hand experience in the industry (once upon a time I did industrial engineering for Hooker Headers) ceramic coating doubles the cost of producing a set of headers, and it is far more than just a coat of paint. It is a self-sacrificing galvanically active coating with far better heat resistance than any powder coating could ever hope to achieve.

Powder coating is a breeze to apply in comparison. Powder coating is just ground up plastic (powder) which adheres by static charge until melted on in an oven.

Ceramic coating starts as a liquid mixture which will not even maintain a solution. The jug of "paint" must be kept in motion on a roller just to keep it in a form of solution. The spray guns are only detail cup sized because there is no point to a larger gun. The paint will settle before you get through more than a couple of ounces.

The prep, curing and polishing processes are all very energy intensive and time consuming.

The end result is a finish which will handle heat better than any other finish available for an exhaust system. The only thing better is to build a system out of stainless steel.
 
I have used the Bank's 4.0L header in the past with great success.

I would take a stainless header over a coated one anyday.

Thorley makes a great stuff too but I've never used their Jeep headers.
 
holy crap
 
I have had 2 banks headers. The first one cracked around one of the runners. They replaced it and the second has had no issues so far. 4 years I think. First header was coated by Swain Tech. They sucked. It took forever to get it done, it was expensive, and the coating looked liked ceiling popcorn texture. It started to fall off and was almost all gone by them time the first header started to crack, about 2 years.

The second header ok had done by Calico Coatings and they were awesome. Way cheaper and done in a week. Finish was nice and smooth and its holding up just fine 4 years later.

Banks also changed the header design due to cracking is what I was told. Guess it's worked so far.

I probably wouldn't go the expensive header route again. By something cheap, have it coated and call it good.
 
Anak said:
I think someone done told you wrong, or a product that is not ceramic coating is being called ceramic coating.

I can tell you from first-hand experience in the industry (once upon a time I did industrial engineering for Hooker Headers) ceramic coating doubles the cost of producing a set of headers, and it is far more than just a coat of paint. It is a self-sacrificing galvanically active coating with far better heat resistance than any powder coating could ever hope to achieve.

Powder coating is a breeze to apply in comparison. Powder coating is just ground up plastic (powder) which adheres by static charge until melted on in an oven.

Ceramic coating starts as a liquid mixture which will not even maintain a solution. The jug of "paint" must be kept in motion on a roller just to keep it in a form of solution. The spray guns are only detail cup sized because there is no point to a larger gun. The paint will settle before you get through more than a couple of ounces.

The prep, curing and polishing processes are all very energy intensive and time consuming.

The end result is a finish which will handle heat better than any other finish available for an exhaust system. The only thing better is to build a system out of stainless steel.
Click to expand...

I got that info from a guy who does PC and that metal spray transfer coating about a year or so ago. It may be BS or I misunderstood. Thanks for the clarification.
 
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