4.0 exhaust header replacement

[dodgerammit]

Hearing the dreaded 'pft-pft-pft' noise from the floorboards. Figuring I'm most likely dealing with a cracked exhaust manifold (header). When I tackle it, I will probably replace the entire system while I'm at it.

Reading very mixed reviews of replacement headers.
Seeing everything from Banks is great, to banks is garbage.
The new Revolver gets really good reviews. Did find a thread where an early version did crack.
Also seeing 'cheapie' flex header replacement is great/garbage.

One thing does seem to hold true is the 2000+ 2 piece factory deals last.
But then I found the ports don't match.

Figures. Find a possible solution, and it doesn't work for my application.

So, what is the consensus from those who have done the replacement?
I'm not after any snake oil BS claims of improvements. I am after bolt on durability. Fix it once and forget it.

Spend the $$$ for a Banks or cheap out and buy the flex header knowing either way, you'll be back in to repair?

Another possibility I've thought of is welding some extra metal gussets to the cheapie flex header for crack resistance. I have access to differing grades of stainless in varying thicknesses.

 

[machoheadgames]

I swapped to the Dorman in 2016. Fit like stock, though the donut gasket was a crappy fit. But it did seal. It was mostly difficult to get the donut onto the new manifold itself.

The Dorman has the flex joints that Mopar implemented into the #1 and #6 on the 98-99 Wranglers. I’m not sure that by itself really makes a difference but that is what Mopar chose to do up until they came out with the new design in 2000.

I haven’t had any cracks but I also haven’t hardly driven the thing since then. Maybe 10K miles at most. I did have the bolts and nuts to the down pipe loosen up multiple times. Ended up replacing both the bolts and nuts with grade 8, and the nuts are all metal locking nuts. I don’t think it’ll loosen again.

I considered Banks for a while, the “new” Revolver has been around for probably 15 years if not longer, and the Torque Tube was before it and known for cracking, while the Revolver was supposed to fix that. I never was sold on the Revolver because it was always much more $ than competition and it had very few reviews that felt trustworthy. Now it seems to have enough that if I had a problem again, I’d try it out.

I thought about getting one of the late Mopars back when I could find them, but they were like $600. Can still find them, but they are still around $600. Mopar 4883385.

Dorman is fine but I haven’t put it through the wringer to say it’s great. I think the stock ones crack so much because of 1) being weak and 2) worn motor mounts allowing the engine to torque over too much which then cracks the weakest link, aka the manifold.

 

[Gilaguy23]

I also used a Dorman on my 95/4.0 and one on a V6 mustang. Like Macho I never racked up much in miles on either but they fit good and they were quiet again This was also about 10 years ago so who knows how the quality is these days.

 

[dodgerammit]

I swapped to the Dorman in 2016. Fit like stock, though the donut gasket was a crappy fit. But it did seal. It was mostly difficult to get the donut onto the new manifold itself.

The Dorman has the flex joints that Mopar implemented into the #1 and #6 on the 98-99 Wranglers. I’m not sure that by itself really makes a difference but that is what Mopar chose to do up until they came out with the new design in 2000.

I haven’t had any cracks but I also haven’t hardly driven the thing since then. Maybe 10K miles at most. I did have the bolts and nuts to the down pipe loosen up multiple times. Ended up replacing both the bolts and nuts with grade 8, and the nuts are all metal locking nuts. I don’t think it’ll loosen again.

I considered Banks for a while, the “new” Revolver has been around for probably 15 years if not longer, and the Torque Tube was before it and known for cracking, while the Revolver was supposed to fix that. I never was sold on the Revolver because it was always much more $ than competition and it had very few reviews that felt trustworthy. Now it seems to have enough that if I had a problem again, I’d try it out.

I thought about getting one of the late Mopars back when I could find them, but they were like $600. Can still find them, but they are still around $600. Mopar 4883385.

Dorman is fine but I haven’t put it through the wringer to say it’s great. I think the stock ones crack so much because of 1) being weak and 2) worn motor mounts allowing the engine to torque over too much which then cracks the weakest link, aka the manifold.

Yeah, all the Revolver reviews except that one I mentioned say they're great and have held up longer than the replacement version. The only threads I can find are from about 2014ish saying people were beginning to try them. The naysayers are the ones claiming they'll crack because of no flex joints.
Nothing as far as recent threads detailing how they did. Just very positive reviews on storefront websites.

I daily mine, so it'll take about 2 years to hit the 10K mark. I wonder if a braided flex joint welded into the head pipe would help prevent the issue with the motor mounts? Mine only has 130K miles, but is still 32 years old.

I also used a Dorman on my 95/4.0 and one on a V6 mustang. Like Macho I never racked up much in miles on either but they fit good and they were quiet again This was also about 10 years ago so who knows how the quality is these days.

This is what concerns me. So many recent comments show nothing seems to be lasting. Mainly poor welds, but I also work with stainless everyday. Mostly in automotive applications. I've noticed the customers are utilizing poorer quality metal more often. Often switching to lower grade stuff when they used to use better. Typically, it's been from 441 (which has more corrosion resistance) to aluminized 409 (which is crap at holding welds regardless what normal 409 does). I prefer 304 if possible for anything exhaust for durability.

 

[dodgerammit]

Well, looks like I'm not the only person who thought about a braided flex section of exhaust installed in the head pipe combined with a quality part for long term durability.
This guy even spring loaded the collector to head pipe bolts so they can move around some.

According to the comments, he is still rocking this without issues.
Looks like I have my answer.
Guess this will happen sometime in the summer once I get the roof repainted and some new springs on the Wagoneer.

 

[TRevs]

I replaced my entire exhaust about a year ago. The manifold was cracked all over. I went the cheap route.

I wanted a cheap, bolt-on option I could do myself since I don’t weld.

I got a complete kit from rockauto, Walker brand I think.

It’s been fine; I think I might have a few minor leaks at the clamped joints but it’s way better than before and I don’t smell exhaust anymore.

Some photos on my build thread:

'95 Sahara, 1st YJ

Yeah those large shims came out, so the pinion is much flatter now. Angle finder says about 9 degree slope, if I'm using it right. That sounds about right. Those shims from OME springs are making the pinion too high, but once you add the tcase drop from them you should be good to go.

wrangleryjforum.com

 

[dodgerammit]

I replaced my entire exhaust about a year ago. The manifold was cracked all over. I went the cheap route.

I wanted a cheap, bolt-on option I could do myself since I don’t weld.

I got a complete kit from rockauto, Walker brand I think.

It’s been fine; I think I might have a few minor leaks at the clamped joints but it’s way better than before and I don’t smell exhaust anymore.

Some photos on my build thread:

'95 Sahara, 1st YJ

Yeah those large shims came out, so the pinion is much flatter now. Angle finder says about 9 degree slope, if I'm using it right. That sounds about right. Those shims from OME springs are making the pinion too high, but once you add the tcase drop from them you should be good to go.

wrangleryjforum.com

Yeah, I'm probably gonna buy the complete downstream exhaust kit myself, but use the Banks Header. I also plan on adding a flex coupling in the head pipe as I put it together. I had to do the same on my Grand Wagoneer due to vibrations cracking the Y pipe. Dunno, I do like the way the Flowmaster FX muffler sounds on these. Just a bit more of the classic 4.0 sound at the tail pipe without trying to make it sound like a v-8 or too loud to enjoy tunes or ride with the top down..

 

[Plastic Fury]

Yeah, I'm probably gonna buy the complete downstream exhaust kit myself, but use the Banks Header. I also plan on adding a flex coupling in the head pipe as I put it together. I had to do the same on my Grand Wagoneer due to vibrations cracking the Y pipe. Dunno, I do like the way the Flowmaster FX muffler sounds on these. Just a bit more of the classic 4.0 sound at the tail pipe without trying to make it sound like a v-8 or too loud to enjoy tunes or ride with the top down..

I am looking at this option myself. I purchased a Banks revolver about 3 years ago for my old 91 YJ but it wound up staying in the box. I just installed it on my 95 Sahara that I have been rebuilding so I cannot comment on longevity but I do like the idea of a flex pipe, like all the FWD cars I have had. I also have a JBA mid pipe for the TJ that brings the exhaust in front of the oil pan. On test fitment, I need to move the mount back a couple of inches as it's pressed right on the Banks header. The angles are not great where it meets the header but stock isn't either. Hoping the lead adapter will seal it up. I hadn't thought about a flex pipe but that is a great idea. I will check out that video as I am currently trying to figure out the rest of the exhaust and what muffler to go with.