Exhaust Manifold R & R - My 2 cents
#1
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Thread Starter
Exhaust Manifold R & R - My 2 cents
Over the past 100k miles I've replaced cracked exhaust manifolds 4 times now. Using Stock OEMs from the stealerships, to Stainless Steel thick wall headers, to name brand header companies. Thats not what I'm writing about here. Although anyone wanting chime in with their two cents on the subject is welcome.
The job to remove the intake/exhaust manifold bolts is a real PITA. And the reassembly is worse. Fighting the intake manifold into place and installing the lower bolts in the blind is shortened with the MtnGoat Method. I found an interesting way to avoid the hassle. Once the manifolds are out a simple modification to the intake is in order. There are two dowel pin alignment lugs that need to be cut down. I used a die grinder and removed the lower half of the lug. This way the manifold can be lowered onto the pins.
So the procedure is simple. Install the gasket then the exhaust manifold onto the pins and studs. Secure these with the two end washer/nuts and the center bolt/washer. Install the LOWER four bolt/washers and turn in 1/2 turn or so as to get these bolts "started" but not to fall out. Also making sure the washers are seated against the bolt head base. Now drop the intake manifold into place, feeling for those pins & half lugs to align. Now install the remaining bolts/washers and torque as required.
This procedure recently saved me a lot of aggravation. And maybe it will help some of you too.
The job to remove the intake/exhaust manifold bolts is a real PITA. And the reassembly is worse. Fighting the intake manifold into place and installing the lower bolts in the blind is shortened with the MtnGoat Method. I found an interesting way to avoid the hassle. Once the manifolds are out a simple modification to the intake is in order. There are two dowel pin alignment lugs that need to be cut down. I used a die grinder and removed the lower half of the lug. This way the manifold can be lowered onto the pins.
So the procedure is simple. Install the gasket then the exhaust manifold onto the pins and studs. Secure these with the two end washer/nuts and the center bolt/washer. Install the LOWER four bolt/washers and turn in 1/2 turn or so as to get these bolts "started" but not to fall out. Also making sure the washers are seated against the bolt head base. Now drop the intake manifold into place, feeling for those pins & half lugs to align. Now install the remaining bolts/washers and torque as required.
This procedure recently saved me a lot of aggravation. And maybe it will help some of you too.
#2
CF Veteran
It may not be the easiest of jobs to change the exhaust manifold, but the 4.0 is the easiest one I have ever changed. My 97 has 240,000 on it and spent it's whole life up here in the rust belt, and I was able to get every manifold bolt out without issue, and the bolts where still in useable condition, but I still replaced them. Generally around here if you have to change an exhaust manifold on a vehicle that's over 10 years old that means you have hours of grinding, torching, and possibly drilling ahead of you to get the old manifold bolts out due to rust, but that hasn't been the case with the 4.0s I have done.
#3
CF Veteran
This was a big problem I ran into with aftermarket headers. Some of the rear bolts where impossible to get to with anything other than a crescent wrench. When designing my turbo manifold this came to mind as there was no reason to make it if I couldn't get it torqued down. After much trial and error I managed to make a manifold with a turbo attached easier to bolt on than even the stock manifold.
On all 4.0s that I own, the back lower 2 bolts get replaced with studs, the rear most is already a stud. This makes locating them fairly easy.
On all 4.0s that I own, the back lower 2 bolts get replaced with studs, the rear most is already a stud. This makes locating them fairly easy.
#4
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Year: 1990
Model: Cherokee (XJ)
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Do this and quit replacing them over and over.
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#8
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Year: 1995
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I found getting the intake on the dowels was not that hard on my 95. From below I was able to visually inspect that the rear one was on and (IIRC) I could see the front one from the engine compartment. Getting a wrench on the bolts was not that big of a deal going from underneath for the back ones with the proper length extensions.
If you're doing the whole exhaust, having the front pipe out of the way was a huge help - it made getting at the bolt super simple.
My biggest problem was that my new front pipe had the O2 bung located at a terrible angle so the sensor runs right up next to the oil pan. I put some "exhaust pipe wrap cloth stuff" on the end to keep the wires insulated from the heat of the pan and it's been running fine for a few thousand miles.
If you're doing the whole exhaust, having the front pipe out of the way was a huge help - it made getting at the bolt super simple.
My biggest problem was that my new front pipe had the O2 bung located at a terrible angle so the sensor runs right up next to the oil pan. I put some "exhaust pipe wrap cloth stuff" on the end to keep the wires insulated from the heat of the pan and it's been running fine for a few thousand miles.
#9
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Thread Starter
The flex joint has not resolved the exhaust cracking issue. This one didn't last 6 months....
So now money is no object. Who makes the best exhaust header/manifold?
So now money is no object. Who makes the best exhaust header/manifold?
#10
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#11
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For fun pop your hood off and drive down the road in high gear and moderate throttle. If it was anything like my experience (with new OEM style motor mounts) you will see your engine dancing around. If it does stop focusing on manifolds and more time focusing on locking that engine in place.
#12
Member
For fun pop your hood off and drive down the road in high gear and moderate throttle. If it was anything like my experience (with new OEM style motor mounts) you will see your engine dancing around. If it does stop focusing on manifolds and more time focusing on locking that engine in place.
#14
Member
I totally agree with you. It just baffles me that ppl would replace crap with even bigger aftermarket crap. If your jeep is a stocker then it's understandable, but it is amazing how many ppl pull the old ones out and replace them with the same thing and then are suprised when they only last a couple months ( guess they like being under there jeep more than being in your jeep on a trail). Its better to spend a bit more once and be good for a few years. After the 4 sets you replace in a couple years you have already exceeded the price of HD mounts
#15
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Followup.
For what it's worth, I replaced both engine mounts two years ago. Since the drivers side mount was destroyed from heat, I wrapped the replacement with a heat reflective material.
I found a Banks header that was affordable and installed recently. They advertised that cracks are a thing of the past.
I'll remain skeptical.....
For what it's worth, I replaced both engine mounts two years ago. Since the drivers side mount was destroyed from heat, I wrapped the replacement with a heat reflective material.
I found a Banks header that was affordable and installed recently. They advertised that cracks are a thing of the past.
I'll remain skeptical.....
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