Exhaust manifold recommendations

[gba88]

Thanks for the replies! I thought I saw the ATP on amazon and a guy had posted pics of major cracks in it. I also found this "omix" one..

https://www.amazon.com/Omix-ADA-176...&sprefix=omix+manifold+cherokee,aps,79&sr=8-1

Yeah, this is a DD so I really can't have it down for more than a day or so at most.

 

[Old Man Minimalist]

Well, I guess I'll find out. I'll check it out good when I get it but the last two looked okay. If anything has me give up on rebuilding my XJ it will be the lack of quality parts availability.

 

[Old Man Minimalist]

My atp cracked not long after installing it, maybe 6 months? Yes, my engine mounts we're good, no I didn't have an exhaust flex. It could have been a poorly made one since they are mass produced in china, probably by someone who doesn't know how to weld stainless or it's a poor quality stainless

Thanks for the replies! I thought I saw the ATP on amazon and a guy had posted pics of major cracks in it. I also found this "omix" one..

https://www.amazon.com/Omix-ADA-176...&sprefix=omix+manifold+cherokee,aps,79&sr=8-1

Yeah, this is a DD so I really can't have it down for more than a day or so at most.

Well, I guess I'll find out. I'll check it out good when I get it but the last two looked okay. If anything has me give up on rebuilding my XJ it will be the lack of quality parts availability.

I just cancelled it. You guys and the guy on Amazon saying the number three tube was smashed to make room was enough to make me nervous.

I'm not sure what I will do. I may take mine to a local professional welder and see if he could fix my cracked OE one. This sucks.

 

[cherokeefan_1]

The welds on my atp were horrible looking, definitely not like hooker or hedman headers. It cracked the same place as my original, where the tubes come together, except it's a much larger crack. Part of the problem is they are stainless, plain steel doesnt have the cracking issue but can rust away, although the ones on my daily driver Chevelle lasted 4+ years before it was taken out of DD status, but they are still fine 20 years later, just rusty

 

[cherokeefan_1]

Rewelding stainless header will just crack again. It's like aluminum, 1 and done. Stainless needs as small a weld and HAZ as possible, and the material matters. I'm tempted to go banks but those also crack. I have a 2000 with the cast manifold I want to ditch to help under hood temps, I don't have California emissions either

 

[maxbraketorque]

Rewelding stainless header will just crack again. It's like aluminum, 1 and done. Stainless needs as small a weld and HAZ as possible, and the material matters. I'm tempted to go banks but those also crack. I have a 2000 with the cast manifold I want to ditch to help under hood temps, I don't have California emissions either

Are you suggesting that going from the 2000 cast exhaust manifold to a tubular stainless header will reduce engine compartment temperatures? I could see this happening for a 300 series stainless steel EM because it has much lower thermal conductivity than cast iron/steel, but do you have any examples of this?

Also, the Banks exhaust manifold for the late model XJ is made from 409 stainless steel which has similar conductivity to cast steel, so I would expect the Banks EM to create more heat than the stock EM because there is more surface area and the tubing is thinner wall.

 

[Old Man Minimalist]

Do we know that the various brands of Chinese made manifolds(the bellows type), Omix, Dorman, ATP, etc. are made differently?

Or is it one manufacturer making them for all the brands. Which would mean it really won't matter whether you buy a Dorman, ATP or Omix.

 

[jeep ride]

My guess would be one manufacturer making them and then re boxing them as needed.

 

[cherokeefan_1]

It's the fact that cast iron is much more mass, nothing to do with actual thermal conductivity. The extra mass radiates heat longer causing more heat soak plus they just flow poorly

 

[cherokeefan_1]

Also. The manifolds are cast iron, not cast steel. There is a huge difference

 

[RCP Phx]

Heat is a benefit "inside" the manifold, that's why I chose a Revolver and had it ceramic coated. It's the best of both worlds as my Underwood temps reduced dramatically!

 

[RCP Phx]

Underhood

 

[Old Man Minimalist]

Since it appears they all crack from the low priced ATP to the high priced Banks, I'm going to see if my local guy can weld it.

He looked at it and said he could do with proper cleaning, heating, rod selection and cooling. I figure I have nothing to lose at this point.

 

[gba88]

Since it appears they all crack from the low priced ATP to the high priced Banks, I'm going to see if my local guy can weld it.

He looked at it and said he could do with proper cleaning, heating, rod selection and cooling. I figure I have nothing to lose at this point.

That might be the best bet. If I could be without the vehicle for a while I'd consider the same. Not sure what I'll end up doing.

My jeep is worth at most maybe 2500...maybe. It's a 99 has about 170k on it and has lived in the RUST belt its whole life. Put about 2 months of body work into it last year to get it to pass inspection and had a guy weld rockers on it.

I know it's getting real close to end of life and I wouldn't have a problem putting money into it if I thought the longevity was there. It simply makes no sense to put a $500+ part on it with $125 worth of hardware since it's basically rusting apart as I type this and that's a fraction of what the thing is worth.

At this point, if I get a year out of a part I guess I'll consider myself lucky because the rest of it may not last that long. It's just a shame that nearly everything anymore has to be throw away. I bought it in 2005, so I guess I've gotten my money out of it at the end of the day.

 

[maxbraketorque]

Also. The manifolds are cast iron, not cast steel. There is a huge difference

I do a lot of work with wrought alloys, so I assumed that manifolds would be cast steel, but after doing a bit of reading, I see that exhaust manifolds are likely to be ductile grey cast iron.

It's the fact that cast iron is much more mass, nothing to do with actual thermal conductivity. The extra mass radiates heat longer causing more heat soak plus they just flow poorly

ok. I guess the idea is that high heat built up during driving will radiate when coming down to idle or low power levels. Makes sense.

I did look more carefully at thermal conductivity values that affect heat transfer rates. Ductile grey cast iron is ~50 W/m-K, while 409 SS is about 28 W/m-K, so the effect of having a much thinner wall for the 409 SS tubing is roughly cancelled by the lower thermal conductivity of 409 SS. The tubular manifold will have higher surface area though because of the greater amount of tubing compared the cast EM.

So you have direct experience with tubular headers lowering under-hood temperatures of an XJ?

 

[cherokeefan_1]

Not other than my 91 ran a lot cooler under the hood than my current 2000. Literally everything under the hood of the 2000 is hot as .... Especially in the summer, never really noticed it that hot on my 91 except in summer. Since everything else under the hood is basically identical, except the exhaust manifold

 

[75SV1]

Not other than my 91 ran a lot cooler under the hood than my current 2000. Literally everything under the hood of the 2000 is hot as .... Especially in the summer, never really noticed it that hot on my 91 except in summer. Since everything else under the hood is basically identical, except the exhaust manifold

The head is different on the 2000+ 4.0L. The exhaust port is smaller.

I also run Ceramic coated headers. I use Doug Throleys. I also used a Pace Setter on my Comanche. And if you think Jeeps are bad, you ain't seen nothing. My '75 Bricklin is like sticking you head in an oven. I'd say 1/2 the heat with ceramic headers. About the same with header wrap.

 

[flyin_ryan]

On my 99 I picked up the $90 stainless header with the bellows built into. It looks to be the last link in the first post of the thread. Also picked up all new bolts and two studs from Dorman. The install went will, no issues at all and even the supplied gasket matched up pretty good to all the ports. It's been on there for three months now and runs like a champ. Also replaced my motor mounts at the same time which caused the cracks at the lower flange section where the primaries all come together on the factory header.

Boostworks, they are a great investment if you were keeping your Jeep!
https://www.boostwerksengineering.com/Jeep-40L-Titanium-Manifold-Stud-Kit-V20_p_39.html

Wow, wish I knew about these before

 

[gba88]

On my 99 I picked up the $90 stainless header with the bellows built into. It looks to be the last link in the first post of the thread. Also picked up all new bolts and two studs from Dorman. The install went will, no issues at all and even the supplied gasket matched up pretty good to all the ports. It's been on there for three months now and runs like a champ. Also replaced my motor mounts at the same time which caused the cracks at the lower flange section where the primaries all come together on the factory header.

THANK YOU for the reply! I applied another round of the jbweld extreme heat junk, but will probably pick up a cheap stainless one eventually and put it on when it gets warmer out. It can't be any worse than what's on it now.

 

[flyin_ryan]

THANK YOU for the reply! I applied another round of the jbweld extreme heat junk, but will probably pick up a cheap stainless one eventually and put it on when it gets warmer out. It can't be any worse than what's on it now.

Honestly I was surprised at how well it was built. The flange end that goes to the head is nice and thick and the collector side is just as good or better than the factory one. I compared them side by side and the stainless piece was just as good or better in each way. Pickup some engine mounts also so when you do this you can easily get to the driver motor mount because they are the reason why the header cracks apart. My mounts looked fine until I actually removed them, once the bolts were loose the rubber just fell apart into various pieces so the looked good but were shot.