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Cracked exhaust manifold

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Old 09-21-2011, 08:43 AM
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Default Cracked exhaust manifold

today while taking a gander under the hood of my jeep. i peered through the mess of wires and pipes and saw what i thought was a crack... upon closer inspection and sneaking my phone down there to take a picture i realized that its a pretty good crack.
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so yeah upon confirming my suspensions i thought to myself... UPGRADE!!!
so below is what im going to get most likely

anyone have any better products for decent price please post a link and any review you have of it. thanks

http://www.ineedparts.com/index.php?...oduct_id=15343
Old 09-21-2011, 10:02 AM
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1) Replace the manifold (obviously...) with whatever your preference.

2) The best fix for this is to install a short flexible section in the downpipe, between the collector and the catalytic converter flange. It need not be long, but it must be flexible.

This happens because the XJ exhaust system is awfully rigid, and really has no "give" to it. As the engine mounts fail (check them...) they allow relative motion between the engine and the chassis - and since the exhaust is rigid, something's going to break (so check your engine mounts as well - I'm sure you'll find that at least one of them is failed/failing. Replace all three, if one is gone. If you don't, you'll get hideously accelerated wear on all of them! Replacing all three only takes a couple of hours with hand tools and a floor jack.)

Some aftermarket exhaust manifolds have flexible sections in the #1 and #6 primary tubes, but even this is only a "Band-Aid" fix. The best place to put the flexible coupling is in the downpipe - you can cut out a section of the pipe and replace it with the flex coupling, and you'll be just fine.

Do this while you're replacing the exhaust manifold, and replace the engine mounts (the driver's side mount is easier to access with the manifolds out of the way,) and you'll be good for another 20-25 years. If you don't replace the engine mounts, you'll be good for another six months, tops. If you don't put in the flex coupling, I estimate failure again in 3-5 years.
Old 09-21-2011, 10:08 AM
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I just recently finished a complete overhaul/replacement/make it like new again and I ordered the same APN header. I could not be happier with it, and it gives the flowmaster a really good sound as a bonus. The install was easy, just be sure and follow the instructions that come with it.
Old 09-21-2011, 10:26 AM
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I went with a Borla header and LOVE it!!!
My '96 already had the Borla Cat-back.
If you are looking to upgrade the system remember that the more air out you can get the more air in you will be able to get in.
I have bored out my throttle body and installed a '00 intake. I've got great power!
Here is a link to a site I try to read often.
He has done so much to the XJ and keeps it looking stock.
http://go.jeep-xj.info
http://go.jeep-xj.info/HowtoExhuast.htm

Make time to read his other stuff.... FYI
Old 09-21-2011, 12:13 PM
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Originally Posted by 5-90
1) replace the manifold (obviously...) with whatever your preference.

2) the best fix for this is to install a short flexible section in the downpipe, between the collector and the catalytic converter flange. It need not be long, but it must be flexible.

This happens because the xj exhaust system is awfully rigid, and really has no "give" to it. As the engine mounts fail (check them...) they allow relative motion between the engine and the chassis - and since the exhaust is rigid, something's going to break (so check your engine mounts as well - i'm sure you'll find that at least one of them is failed/failing. Replace all three, if one is gone. If you don't, you'll get hideously accelerated wear on all of them! Replacing all three only takes a couple of hours with hand tools and a floor jack.)

some aftermarket exhaust manifolds have flexible sections in the #1 and #6 primary tubes, but even this is only a "band-aid" fix. The best place to put the flexible coupling is in the downpipe - you can cut out a section of the pipe and replace it with the flex coupling, and you'll be just fine.

Do this while you're replacing the exhaust manifold, and replace the engine mounts (the driver's side mount is easier to access with the manifolds out of the way,) and you'll be good for another 20-25 years. If you don't replace the engine mounts, you'll be good for another six months, tops. If you don't put in the flex coupling, i estimate failure again in 3-5 years.

excellent advise>
Old 09-22-2011, 04:37 AM
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Originally Posted by 5-90
1) Replace the manifold (obviously...) with whatever your preference.

2) The best fix for this is to install a short flexible section in the downpipe, between the collector and the catalytic converter flange. It need not be long, but it must be flexible.

This happens because the XJ exhaust system is awfully rigid, and really has no "give" to it. As the engine mounts fail (check them...) they allow relative motion between the engine and the chassis - and since the exhaust is rigid, something's going to break (so check your engine mounts as well - I'm sure you'll find that at least one of them is failed/failing. Replace all three, if one is gone. If you don't, you'll get hideously accelerated wear on all of them! Replacing all three only takes a couple of hours with hand tools and a floor jack.)

Some aftermarket exhaust manifolds have flexible sections in the #1 and #6 primary tubes, but even this is only a "Band-Aid" fix. The best place to put the flexible coupling is in the downpipe - you can cut out a section of the pipe and replace it with the flex coupling, and you'll be just fine.

Do this while you're replacing the exhaust manifold, and replace the engine mounts (the driver's side mount is easier to access with the manifolds out of the way,) and you'll be good for another 20-25 years. If you don't replace the engine mounts, you'll be good for another six months, tops. If you don't put in the flex coupling, I estimate failure again in 3-5 years.
i was looking at the engine mounts today too. i only saw two, where is the third? the two i saw seemed fairly good. because they were replaced at some point. i remember that the shop noticed it so they replaced it. not sure if it was all. the two i saw were to the left and right, where do i look for the third?
Old 09-22-2011, 06:48 AM
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Originally Posted by Mendax13

i was looking at the engine mounts today too. i only saw two, where is the third? the two i saw seemed fairly good. because they were replaced at some point. i remember that the shop noticed it so they replaced it. not sure if it was all. the two i saw were to the left and right, where do i look for the third?
Uhhhh... As far as know there only is two. The other mount you may be talking about is the tranny mount which should be replaced when youdo motor mohbta
Old 09-22-2011, 07:22 PM
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Originally Posted by Mendax13
i was looking at the engine mounts today too. i only saw two, where is the third? the two i saw seemed fairly good. because they were replaced at some point. i remember that the shop noticed it so they replaced it. not sure if it was all. the two i saw were to the left and right, where do i look for the third?
The third is between the transmission and crossmember - since it's replaced when doing the engine mount job, it's lumped in with the engine mounts.

Doing a "partial replacement" of engine mounts often leads to accelerated wear.

Quick test for engine mount cushions:
- Use a 1/4" knitting needle.
- Press the pointed tip of the needle into the "rubber" block, using simple thumb pressure.
- If the point penetrates the surface, or intents it more than about 1/4" inch, replace the mounts. (Any one fails, replace all three.)
- If the surface of the elastomer does not immediately and fully recover once pressure is removed, replace all mounts.

"Thumb Pressure" means, generally, 5-10# of applied force.
Old 09-28-2011, 04:01 AM
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i found someone willing to sell me a 2000 intake manifold for 65$ is that good? after that im going to buy the exhaust and then injectors and swap everything at once. at least thats my plan.
Old 09-28-2011, 09:32 AM
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$65 vs. $159 for the new APN.....depends on how much you like wrenching....stock exhaust manifold IS going to crack eventually. It isnt the quickest or the fastest job to pull the intake and exhaust, and then put it all back together....I guess if you need to save $100, and you have alot of extra time, the $65 is ok.....just depends on your situation.....


Ooops.....misread....you said INTAKE.....my bad...
Old 09-28-2011, 12:02 PM
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http://store.sandmansauto.com/autopa.../type/MANIFOLD

My Dad's TJ ate two headers in the first half of its 320k. He found and put this one on and it's been there since.

And it's cheap.
Old 01-05-2012, 05:36 PM
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Originally Posted by Jmb94
http://store.sandmansauto.com/autopa.../type/MANIFOLD

My Dad's TJ ate two headers in the first half of its 320k. He found and put this one on and it's been there since.

And it's cheap.
Pulled the trigger on this guy. Not looking for performance and something tells me your Dad knows what he's doing. I'll post photos of it when I get it for you guys.
Old 01-07-2012, 09:05 PM
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Photos as promised:







Came with gasket, new flange bolts and this weird thing (that I'm still figuring out):



I'm guessing it's a mani to exhaust seal/gasket of sorts?





Figure it sandwiches in between?
Old 01-07-2012, 11:01 PM
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all that makes it crack is the difference in the length of the tubes going into the manifold its just a bad factory design if you get an aftermarket it will be fine but still sucks
]

an additional flex tube in the exhaust is just stupid theres no need they came without one for a reason

Last edited by nismo5; 01-07-2012 at 11:04 PM.
Old 01-08-2012, 11:55 AM
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"That weird thing" you don't know where it goes is a high-temperature fibre flange packing (commonly referred to as a "donut gasket,") and it goes exactly where you think it goes.

If your counterman is on the ball, you can ask for a "donut" for your vehicle and that's exactly what you'll get (it's the only gasket referred to as a 'donut' in the whole vehicle.)


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