Side Pipe Failure

[Blitzboy54]

Gents,

First and foremost I would like to publicly say that if you are building one of these cars and Jeff Kleiner says to do or not to do something please do yourself a favor and follow his advice.

Despite warnings in this forum I did in fact secure my side pipes with 2 bolts on the tab and not one (at the end of the day the manual said to do it and I thought it is what I should do). As a result my passenger side the tab has torn from the pipe on the side as you can see from the pictures. I removed the bottom bolt from both sides and reached out to FFR. I accept some responsibility because even though the manual says to secure it with 2 bolts the forum says not to do it. As a result I am not asking for "warranty coverage". Since my pipes are ceramic coated they need to be stripped, welded then re coated. I would like to get a new one coated and replace it, this seems like a better option then the alternative. I have also purchased the parts necessary to create a front hanger at the side pipe/Jpipe junction to take the future load off.

I reached out to FFR to ask if I can purchase just the passenger exhaust seeing that they are made in house. They said no, they will only sell me a pair. I have to say I am a little annoyed about that. I'm willing to pay shipping and pay retail for the replacement pipe. I am running this by the board to see if I am on solid ground here of if I am out of line. Sometimes when your emotional you see things differently, I respect the collective advice of the board.

As an aside the grey material you see there was just some gasket sealer. I was a couple hours from home when I discovered it so I stuffed some goop in there for containment (as you can probably guess it didn't do a whole lot lol)

[J R Jones]

B Boy, Your experience is a combination of hydrogen embrittlement at the weld and a load/fatigue leading to fracture failure.
This is common to auto and motorcycle racing. As mentioned in a similar thread a couple of weeks ago a (mesh) flex joint between the headers and side pipe would adsorb the amplitude of shake.

A basic technique of welding a support tab to thin tube is to spread the load and provide some flex. This is accomplished by making the tab two (thinner) asymmetrical 90 degree tabs. The leg segments parallel to the tube are welded to the tube forward and aft of the joined mount surfaces.
The objective is to spread the weld across as much tube surface as possible.
IMO one or two fasteners does not contribute to this failure, design is the problem.
jim

[Jeff Kleiner]

Just have it repaired by welding a 1 1/2"- 2" square to the area of the pipe that tore away then weld the tab to that. When you reinstall it use only the top bolt---snug with a Nylock, not tight You could have the whole works recoated but really, it's in an area that is virtually unseen unless you're under the car so if you were to simply paint the repaired area with some high temp black you're probably the only guy who will ever notice.

Yes Jim, it is a design problem but after installing over 100 with only one bolt and never having one pull the tab loose I have to say that one or two bolts does contribute. Two bolts torque the tab when the pipes move which can ultimately lead to a fracture like Jesse's. One bolt that is merely serving as a hanger does not.

Jeff

[rich grsc]

If the tab is not completely torn off, cut a slot in the piece of metal Jeff suggested, slip it over the tab then weld it. Try to shape the patch piece to match the curve of the pipe.
As Jeff says, use one bolt. I have not torn the tab off a side pipe in over 15 yrs since I did it that way.

[J R Jones]

Guys, I neglected to include another mount detail. On our tube mount tabs we always weld the mount tab inline with the tube, not perpendicular. Then the welds at the tab edges lay along the length, not the circumference.
In this case the tabs are stressed along the root, and perhaps can micro flex. That is standard practice on OEM car and motorcycle mufflers; tens of thousands.

One fastener or two, I assumed you create a solid connection but it now seems to me you create a fastening joint to accommodate movement. To each his own.
jim

Honda Muff Mt.jpg

Honda Muffler.jpg

[rich grsc]

I can see you don't know much about these builds

[Nigel Allen]

I can see you don't know much about these builds

Ease up mate.

[Jeff Kleiner]

Facts Nigel

Jeff

[danmas]

I have a couple of side pipes I wont be using. Happy to part with them if you are interested. PM me.

[Dave M]

I repaired mine the same way Rich suggests maybe 12 years ago put them back with one bolt and have had no issues since.

[GoDadGo]

The problem is the geometry of the mount (Rotation) is different from that of the engine rocking back and forth.

I really think that the hanger design needs to be redesigned or you can simply place one bolt in each muffler mount with One Metal Jam Nut & Bolt on each side that allows the pipe to rotate a bit. Washers can be placed in between the mount and the muffler to better allow some additional rotation but be advised that the bolt cannot be totally tight.

As for me I modified my mounts so that the pipes can float more freely, with only one mounting point to the frame of the car using heavier rubber hangers. In addition I am running very stiff polyurethane engine and transmission mounts which limits engine movement, specifically that back and forth rocking rotation under power and downshift engine braking. So far things appear to be okay so I'm hoping I don't have to deal with this issue that others have been plagued with.

Good Luck To All Who Are Experiencing This Problem!

[Steve in Snohomish]

GoDadGo, Could you post a picture of your modified mount? I'm getting close to this point in my build.
Thanks.

[Blitzboy54]

I have a couple of side pipes I wont be using. Happy to part with them if you are interested. PM me.

Thank you! That is a very generous offer. A local builder reached out with something similar. Let me touch base with him first. He will definitely reach out if that doesn’t work.

Again, many thanks

[boat737]

The old side pipe hanger problem. It took me a month of thinking and pondering, but I came up with what I think, I hope, is a good solid fix. My hanger design is articulated on both ends with Heim joints, and allows the muffler to articulate and move in all directions, in-out, up-down, fwd-aft, yet still provides for upward support. A bonus is, it is somewhat adjustable. I have it set to provide about 20 pounds of lift. It's been on for about 6 years now. So far, so good. Time will tell if my design will hold up.

[Mark Reynolds]

I'd repair the pipe.
Jeff's solution is a big and easy improvement for those with finished cars.
A usual I have a slightly different take on it.
Basically the pipes need to move with the engine and they are overly constrained because the inboard ends of the hangers resist side to side movement.
Think of the rubber hangers as dampers. The side-pipes are springs. The rubber hangers should be installed basically neutral, neither pulling up nor pushing down on the pipe. Weld a bolt into the elbow of the hanger arm or a new hole depending on where the rubber hanger intersects it. Then cut off and remove the part of the arm inboard of the rubber hanger including the rubber puck. Retain the rubber hanger on the bolt with a self locking nut and washer. It does not need to crush the rubber hanger. I found I needed to put a shallow z bend in the hanger arm to get it to lay flush against the hanger on one side only. In this way you can use both screws to attach the arm to the sidepipe tab without over stressing the tab.

[Avalanche325]

Also don't just leave the hangers off. That was the word on the street a few years back. Then you get to have your headers welded.

[GoDadGo]

GoDadGo, Could you post a picture of your modified mount? I'm getting close to this point in my build.
Thanks.

Sorry that I don't have any pics of what I did; however, please know that all I did was cut the long end off of the bracket (Inboard Section) and install a heavier duty rubber hanger....It was literally that simple, but please keep in mind that my engine doesn't move and/or rock very much because of the very stiff engine and transmission mounts.

I'll try to get under the car this weekend when I return home.

[Jeff Kleiner]

Also don't just leave the hangers off. That was the word on the street a few years back. Then you get to have your headers welded.

Exactly! We get photos like these with guys asking "Why did this happen?"



And then when we dig deeper they confess that they were running without hangers

Jeff

[Legendary]

This is an interesting read for a newbie. Didn't know the tabs could break if you put two holes in it. I hope I remember that when I get to that section of the build.

[Blitzboy54]

Gents,

As always the forum has come to the rescue. Our old friend NYMike reached out and sent me his un used set from his build. I have lots of options now. I will send that set out for coating and also repair the pipe I have in the meantime.

I have removed both lower bolts and took the tight out of the lock nut so it is more of a hinge. I have also created these brackets to support the sides and hopefully take the strain off the Jpipe (in my case cats). I fired up the engine and rev'd it aggressively and these seem to do the trick. Thanks and again DO WHATEVER JEFF SAYS!

[Joel Hauser]

As they say, an ounce of prevention is a worth a pound of cure. This morning I removed the lower hanger bolts, and loosened the upper so the sidepipe can move a bit. Thanks for starting this thread, Jesse. Hope to see you at some car shows and Cruise ins this summer.

[Steve in Snohomish]

boat737, Your hangers look good and simple. You wouldn't happen to remember what the dimensions are? (length of bar an hole locations). I'm thinking this might be the way to go for me.
Thanks,
Steve

[boat737]

boat737, Your hangers look good and simple. You wouldn't happen to remember what the dimensions are? (length of bar an hole locations). I'm thinking this might be the way to go for me.
Thanks, Steve

OK here ya go. Sorry for the length of the narrative. Guess I got carried away. Here’s the dimensions, and parts list (McMaster-Carr parts numbers), the best I can come up with, being 6 years later with some brain fog mixed in.

As for the fasteners, they are all 5/16 – 18. I use stainless, but that is optional. Some are hex head, some are allen-socket head, again mostly optional. The two nut-certs (each side) are also 5/16 – 18. I used shoulder bolts (not fully threaded), so there were no threads in the rubber hanger connector, in the helm joint ball, etc. The lock nuts on the muffler tab were the high heat kind, all metal. The other nuts were ny-locs.

Originally, I was going to use 3 heim joint (ball-end joint) on each hanger, but that ended up being to free and wobbly. So, there are only 2 heim joints on each hanger, one on the muffler tab, and the other on the 2”x2” crossmember, inboard end of the hangar. The part that connects that inboard heim joint to the end of the bar hanger is a blank rod end. The blank rod end has to be drilled for a 5/16 bolt, and threaded 5/16 – 24 to screw into the heim joint on the 2x2 mount. (I never could find a finished solid rod end, but maybe someone makes it. It wasn’t that hard for me to do my own drilling and threading on the blank rod end.)

The distance between the holes on the bar hanger is 6 7/8 inch, and between the nut-cert mounting points in the 2x2 is about 5 1/2 inches. Those dimensions are not that critical. Also, you’ll notice that they are not the same dimension on the 2x2 as they are on the hanger bar, and that’s intentional.

I tried to mimic the movement of the hanger bar, to the movement of the engine with torque. Under load, or back loading, the engine moves some in the rubber motor mounts. When that happens, the muffler moves up and down, and in and out, as well. Having two different pivot dimensions on the hangar, it will also move out-and-up or down-and-in with the muffler movement. I’m sure it’s not exact, but it’s my best guess.

As for the vertical placement of the nut certs, I was aiming for roughly in the middle of the 2x2. They will be a little different from DS and PS, due to the fact that the mufflers will most likely not be at the same height with each other. Hopefully within a half-an-inch of each other, but could be more on your build. You’ll notice on my coupling nuts, I welded them at slightly different heights/angles. That was due to the slight difference in muffler height on mine.

It’s best to keep the hanger as high as possible, without rubbing on the body or frame. So I cut out about an 1/8 inch or so on the bar to conform around the bottom of the body. There is about 3/16 (PS) to ½ inch (DS) clearance between the bar and the body lower edge. There is no evidence that the bar has touched body during operations.

The way I ended up laying it all out, was to start at the muffler end, and work inward. Start with the Heim joint on the muffler tab, to the coupling nut (or you could just weld or permanently attach the heim joint to the hanger bar), coupling nut to the hangar bar, to the rubber hanger, to the inboard solid rod end, finally to the inboard heim joint. Again, it doesn’t have to be ultra-precise, due to the difference in muffler position.

After it was all together, I added a small strip of high-density rubber between the inboard heim joint and the 2x2 member. It stabilizes it a bit more. I just added a couple small nut-certs and screwed it on.

Hopefully, between the pictures in the prior post, and here, it will make enough sense.

Good luck. Hope this helps.