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Discussion Starter #1
Here are the new MagnaFlow short headers with cats attached. Initial look over shows they are not too bad on quality. A quick check of flange straightness showed about .030" bow in both from welding. I have an old heavy table saw from the early 70s that has a cast steel top that is milled so I put a couple of 80 grit sanding disks on it and ran the new manifold across and you can see they aren't flat. Also you can see what I am up against with the old rusted hardware. I've been soaking the old hardware with penetrant for about a week and have had some success in getting a few of these to unscrew, but I am prepared for a big fight to get the rest out when it comes time to finally get the new manifolds installed. Right now I am still gathering parts, I have all new studs, nuts and gaskets. The new manifolds are stainless so we will just have to see how they hold up to heat cycles and cracking. These aren't seamless tubing, which would contribute to potential cracking. I can see that the engine compartment will definitely see higher temps from radiant heat. I might wrap these but that would mean more maintenance because I would not know if they have cracked unless I unwrap them.
 

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You can have them ceramic coated (inside and out), I've done that on vehicles I've fitted with tubular manifolds and its worked very well on controlling underhood heat and the droning noise which tubular headers sometimes ends up making inside of the cabin. In fact, you can have all of the pipes coated (inside and out) and the mufflers (mufflers get outside, only, obviously).

Wrapping mild steel headers tends to lead to corrosion and early failure, due to salt water "sponge" the wrap provides.

Regarding rusted hardware: easiest simply to blow them away with an oxy acetylene torch, if you've got one, or a nut splitter & cutting wheel are also effective. Wrenches, not so much.

When installing the new fasteners, use lots of copper anti-seize coating, everywhere, for next time (works wonders).

N
 

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Discussion Starter #3
Norm,
Thanks. Yes the hot wrench...I need to find replacement tanks for my oxy/act because I ended my tank rental (live and learn...sigh). These headers are stainless seamed tubing. Thanks for the tip on ceramic coating, I'll have to spend hours online researching that now.....

You can have them ceramic coated (inside and out), I've done that on vehicles I've fitted with tubular manifolds and its worked very well on controlling underhood heat and the droning noise which tubular headers sometimes ends up making inside of the cabin. In fact, you can have all of the pipes coated (inside and out) and the mufflers (mufflers get outside, only, obviously).

Wrapping mild steel headers tends to lead to corrosion and early failure, due to salt water "sponge" the wrap provides.

Regarding rusted hardware: easiest simply to blow them away with an oxy acetylene torch, if you've got one, or a nut splitter & cutting wheel are also effective. Wrenches, not so much.

When installing the new fasteners, use lots of copper anti-seize coating, everywhere, for next time (works wonders).

N
 

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It looks like you have some side-access to the rusted nuts. The worst thing you could do would be to break off a stud in the head; that would likely require you to pull the head to EDM the stud out to avoid any possible damage to the head.

After soaking with multiple applications of penetrating oil for a week, apply a conservative amount of torque and see if the nuts will will break loose.

If not, use a length of 3/8" or 1/2" steel rod and a ball-pein hammer and sharply rap on the sides of the nuts 10-15 times, then try the conservative torque again.

Sometimes the nuts will stay locked on the stud and the stud will unscrew from the head. If you can easily get the studs out, replace them all with new parts. There is nothing more frustrating than installing new exhaust plumbing, carefully torquing everything, and having an old stud break two weeks later.

If it appears that the nuts are effectively "welded" to the studs via extensive corrosion, use a nut-splitter to split the nut, and you can unscrew it with your fingers. You can use a socket & long extension to apply the torque to the splitter.

Torching the nut off usually takes the stud with it, and then removing the remaining stud can become the next challenge.

Given the level of corrosion shown in your photos, that engine bay has seen its share of road salt, and I'd be very careful of damaging the studs.
 

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Discussion Starter #5
Thanks for the concern in removing these. Yes, the rust has taken over. I got caught in a snow storm in western PA and they had sprayed magnesium chloride. It has just about ruined my aluminum trailer also. Nasty stuff that is very expensive to repair the damage done by it. I have already had some success removing four of the nuts/studs on one side. I have not attempted to remove anything on the other yet. When you use a torch (well this is how I do it) you heat the stud/nut red hot and let it cool then apply torque. It is a way of shocking the hardware to give up it's position in the head. I don't plan on burning these off, just persuading them with heat. I have all new hardware as mentioned in my above post. So far no broken studs.


It looks like you have some side-access to the rusted nuts. The worst thing you could do would be to break off a stud in the head; that would likely require you to pull the head to EDM the stud out to avoid any possible damage to the head.

After soaking with multiple applications of penetrating oil for a week, apply a conservative amount of torque and see if the nuts will will break loose.

If not, use a length of 3/8" or 1/2" steel rod and a ball-pein hammer and sharply rap on the sides of the nuts 10-15 times, then try the conservative torque again.

Sometimes the nuts will stay locked on the stud and the stud will unscrew from the head. If you can easily get the studs out, replace them all with new parts. There is nothing more frustrating than installing new exhaust plumbing, carefully torquing everything, and having an old stud break two weeks later.

If it appears that the nuts are effectively "welded" to the studs via extensive corrosion, use a nut-splitter to split the nut, and you can unscrew it with your fingers. You can use a socket & long extension to apply the torque to the splitter.

Torching the nut off usually takes the stud with it, and then removing the remaining stud can become the next challenge.

Given the level of corrosion shown in your photos, that engine bay has seen its share of road salt, and I'd be very careful of damaging the studs.
 

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When using the torch heat the nut until cherry to expand it. You'll heat the stud but it won't get cherry and the nut will come off. Some location are going to be hard to use a torch but it's another tool in your toolbox.
 

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I have used the torch method many times, but I'm a little leery to recommend it on an open forum for use in an engine bay. I've seen it "go wrong" for others several times when someone only focuses on the tip of the flame, and is not watching something else 8 inches away.

Actually there is no need to heat the nut cherry red to expand it sufficiently to break it loose, even if severely corroded. Brush a little engine oil on it, then heat THE NUT ONLY gradually with a pinpoint propane torch. Every 15 seconds move the flame off the nut, and see how the oil is smoking. As soon as it is REALLY generating white smoke, it is around 500F, is well-expanded, and ready to try removal. Work quickly, and you won't substantially heat up your socket if you dump the nut out as soon as it is off the stud.

Heating the stud any more than the minimum required to remove the nut is a bad idea as these are typically higher tensile strength, heat treated fasteners. Heating them visibly red hot anneals them and substantially softens them.
 

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Discussion Starter #11
I agree with the idea not to heat the studs too much. So far I have 8 of the twelve that have "cooperated" so 4 are going to "problem" children. I might just weld new nuts onto the part of the stud that is exposed. I am having some trouble replacing my old rented oxy/act tanks, but I have MIG and TIG welders available. Stay tuned....



I have used the torch method many times, but I'm a little leery to recommend it on an open forum for use in an engine bay. I've seen it "go wrong" for others several times when someone only focuses on the tip of the flame, and is not watching something else 8 inches away.

Actually there is no need to heat the nut cherry red to expand it sufficiently to break it loose, even if severely corroded. Brush a little engine oil on it, then heat THE NUT ONLY gradually with a pinpoint propane torch. Every 15 seconds move the flame off the nut, and see how the oil is smoking. As soon as it is REALLY generating white smoke, it is around 500F, is well-expanded, and ready to try removal. Work quickly, and you won't substantially heat up your socket if you dump the nut out as soon as it is off the stud.

Heating the stud any more than the minimum required to remove the nut is a bad idea as these are typically higher tensile strength, heat treated fasteners. Heating them visibly red hot anneals them and substantially softens them.
 

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Does that kit have manifolds included? If not you won't need to go through the wonderful experience I am...!:mecry:
this kit does not have manifolds or headers included , my understanding is headers don't help our trucks that much if any , anyone else have an opinion on that ?
 

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Discussion Starter #13
I need to replace my original manifolds as you can see in my initial post. If you can salvage your original manifolds you will be better off. I can't so these MF shorties are a good answer hopefully. I have read a number of posts here about error codes showing up after deleting a set of CATS. I don't want to go through that but we will have to see how these perform.



this kit does not have manifolds or headers included , my understanding is headers don't help our trucks that much if any , anyone else have an opinion on that ?
 

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Ok yeah makes since ... this kit I’m looking at deletes the front cats and is setup not to throw any codes ...so this setup would be an option with long tube headers also
 

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Discussion Starter #15
Ok, so far no broken studs. I have one side complete (new studs and nuts) with ALOT of high temp nickel anti-seize. I can't have my FJ down for too long as it is my daily driver so I am replacing things a little at a time. First studs and nuts then the shorty headers. I am still trying to decide what I want to do for the CAT back section, so it may take some time to get to the headers. Any suggestions for CAT back? I have had some success on the other side as you can see by what's left of the new parts, only four studs to go. I used one new nut on an old stud. Wow getting a MIG torch in next to the manifold and then pulling the trigger was definitely no fun. I have a lift so it did make things easier. I snaked the torch handle down from the top and then grabbed it through the wheel well after raising the FJ so I could work next to the shock tower. Lot's of hard work but so far so good. The hardest one was behind the alternator. I am guessing I have about six hours into these replacements and another couple hours to go. I can see why shops would charge so much to replace manifolds. The main problem with the rusted hardware is that the nuts are no longer 12mm so it has been a chore trying to find the correct socket to fit. Most were 11mm but a few were in between 11 & 10mm so the nuts got rounded off. The torque to break these loose was probably close to 50 ft lbs (two foot wrench with 25 lbs applied) so if the socket wasn't right, around it would go. Below is the carnage....
 

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Yeah those as bad but I’ve seen worse , bolts coming out look in fairly good shape at least , let us know when you finish up
 

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@ZoSoIV IMHO I don't care for tube headers either. I've not had good experience with them. In the day, not recently and not on the FJ.
Leaking, fit, noisy. Maybe now better material, workmanship, flanges etc ??

@MajorMinor I have URD Stainless 3″ Mark3 Exhaust. $589.00 price is from URD website. Nice sound on my FJ, no droning. Tucked up.

https://www.urdusa.com/urd-stainless-3-mark3-exhaust-fj-cruiser-2007-2014

I recently helped grandson with headers on his Corolla (please don't ask). Under hood temp too high. Had them coated inside and out. Really helped. If only the FJ was so easy to work on. They fit like crap but hey I'm an old guy what do I know. :grin

edit: I will add the Corolla headers were cheap! I wouldn't use the term inexpensive. Cost more for the coating than the headers. With help from the shop, got them modified a little so fit wasn't so bad.
 

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So in my past experience with long and short tube headers, shorty headers only gave about 20hp increase. Balanced with low speeds and increased underhood temps and possible reliability issues, is it worth it?
 

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Discussion Starter #20
So in my past experience with long and short tube headers, shorty headers only gave about 20hp increase. Balanced with low speeds and increased underhood temps and possible reliability issues, is it worth it?
Wow 20hp that would be great. I am not too sure what you mean by reliability issues? I am having these coated with cerakote this week for the under hood temps. Just a note that I am not looking for a performance upgrade with these headers, that's not why I bought them. These are stainless steel so I am hoping that they won't rust as bad the original mild steel and they have the CAT already welded to them. I am looking to replace my rusted original manifolds that's it. I have never been in a situation with my FJ that I thought it was under powered, it has performed perfectly for the 11 years I have owned it.
 
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