Header Reducer Question

[84Toyota4x4]

On my Toyota, I had to find a header reducer that would fit my unknown brand header when I originally built the exhaust. It lasted 4 years until it gave out the other day. The flange (flair?) on the reducer that seals to the header has cracked and broken off, thus allowing the pipe to move around inside the triangular clamp ring, no matter how tight it was, providing a nasty exhaust leak.

When I built the exhaust the first time, I welded that reducer to the pipe immediately following it, which I had custom bent. When the reducer failed, I was somewhat forced to replace that whole bent pipe because I didnt want to fight with grinding the welds and trying to pull it out, cutting it off and having the pipe be too short, etc. The pipe itself was looking pretty shabby and flaking pieces of rust off as well, although it was still very sound. I decided to just replace the whole pipe and reducer to save time and effort even though it probably would have still lasted much longer.

Now then, I have the second reducer that came in the original pair, and a new bent pipe. Do I weld this reducer on, or can I simply slip fit it with some sealant and a clamp so that should it fail again, I may be able to replace just the reducer?

What is common practice for installing these things? I see a lot of them in the parts stores now are coming either chromed or plated in some way, I assume this means people aren't welding them on? When I bought mine the first time 4 years ago, they were all just bare metal in the store. I actually had to call around to find a place that sells them in bare metal still before I found the second one I had.

~T.J.

 

[TigTorch]

Not a lot of action on this, so I'll throw out my humble opinions from personal experience:

Welding the exhaust system is the only way to go. I definitely would not use sealant anywhere-it wont last. Also, the idea of clamping a slip joint so that its removable later dosent work in my experience. Those muffler clamps with the "U" bolt and the saddle actually crimp the pipes togeather and you will have to beat and pry the snot out of the pipes getting them apart (if you even can) until they're pretty much destroyed. Much, much quicker to do a clean cut and reweld. You want a removable bolted joint somewhere in the system, (which you have at the header outlets), weld everything else.

Your original joint at the reducer just back from the header 3 bolt flange shouldn't have cracked; something is not right. You must be hanging too much weight on that joint or maybe it wasn't able to flex with the motor movement. Cleverly placed hangers are the answer.

I'd weld the new joint/reducer on but make sure its not preloaded. Support the exhaust pipe weight with hangers that can flex side to side a little.

Don't worry about welding chrome plating, just grind it off if you cant find a bare unfinished piece.

 

[84Toyota4x4]

Not a lot of action on this, so I'll throw out my humble opinions from personal experience:

Welding the exhaust system is the only way to go. I definitely would not use sealant anywhere-it wont last.

I have the black exhaust sealant crap that you use on slip fits. Ive had good luck with it in the past not leaking. Same stuff we used in the shop to reseal stuff up with. VERY tacky and nasty, and dries in a weird semi solid state once heated with the exhaust. Its basically like tar, but opposite. Its liquidy when cold, and dries semi hard after being heated.

Also, the idea of clamping a slip joint so that its removable later dosent work in my experience. Those muffler clamps with the "U" bolt and the saddle actually crimp the pipes togeather and you will have to beat and pry the snot out of the pipes getting them apart (if you even can) until they're pretty much destroyed. Much, much quicker to do a clean cut and reweld. You want a removable bolted joint somewhere in the system, (which you have at the header outlets), weld everything else.

I just heat them up with the torch and they come right undone. The way my system was built was the reducer with 3 bolt flange welded to the bent pipe, slip fit into a Flowmaster with clamp, slip fit out of the Flowmaster with clamp, and then all welded pipe from there back. When I took it all apart, I just heated up the Flowmaster to take out those crimps, then I spun the pipe in it with channel locks until it was loose, and it slid right out.

Your original joint at the reducer just back from the header 3 bolt flange shouldn't have cracked; something is not right. You must be hanging too much weight on that joint or maybe it wasn't able to flex with the motor movement. Cleverly placed hangers are the answer.

It was the actual flair of the reducer that meets the header. It was the last 1/8" or so around the entire circumference of the reducer that cracked. Its basically the point where the triangle clamp ring makes contact with the flair in the reducer. The clamp ring scored the pipe I assume, because it cracked right along that contact point. The metal of the flair is rather thin at that point. Im using the stock hangers with new rubber isolators, and the exhaust is aligned very well. So well in fact that even with it broken, it hung aligned well enough a good 90% of the exhaust was still going through the system, and I didnt notice it was even broken until I tried to take it apart.

I'd weld the new joint/reducer on but make sure its not preloaded. Support the exhaust pipe weight with hangers that can flex side to side a little.

As I said, when I first built it I was very careful to make it line up right as not to stress anything. Hence why I had the one piece custom bent instead of just "making it fit". I also reused the stock hangers. With the exhaust just hanging in the hangers and slip fitted together without clamps or anything, the pipe lines up damn near perfectly with the outlet of the header.

Don't worry about welding chrome plating, just grind it off if you cant find a bare unfinished piece.

Im not too worried about this since I managed to find my second unplated reducer, as well as a store that sells unplated ones.

Im still up in the air if I want to try and just clamp it. I figure, if it gives me problems, the worst that can happen is I end up welding it. But, if it works clamped and the thing fails again at the same point, I will be able to replace just that one piece.

~T.J.

 

[84Toyota4x4]

This is where the original one failed (along the yellow line). Its right where the clamping ring makes contact with the flair. Basically, the clamping ring was holding the broken off pieces in place, but the center and the rest of the pipe were not really attached. About 75% of the flair was broken off, with the small remaining part holding it in place.

~T.J.

 

[84Toyota4x4]

Another point someone mentioned to me today was that if the old one lasted 4 years and the pipe could use to be replaced anyway, its probably worth it to just weld the new one on. 4 years from now if it breaks again, theres no point in putting a new reducer into an old pipe that could use replacing anyway again.

I will probably just end up welding it, haha.

~T.J.