| Author | Message | ||
| Nick Morris (Nick3751)
Rating: N/A |
Not if your muffler clamps right to your manifold. As most of you know I just had the head off my 671 cause that was the only way to pull the muffler other than pulling the engine. So since I couldn't find one to buy I had one built, out of stainless. Man it was all shiny and pretty, all the while I'm thinkin this thing is going to outlast the bus the engine and me, the kids could have it when they bury me(in the bus). Well let me tell ya a little secret that I knew had I thought a little further down the road. Now I know there may be some that does but for the most part my experince is that stainless doesn't do well with large temp. extreams. Well when the thing is clamped to the manifold directly with no pipe between (as a lot of ours are) as you who have pyros can atest there can be a lot of heat at one end of a muffler. To make a long story short my brand new $600 muffler with about 300 miles on it has cracked all to pieces. I still have a the important stuff so the next one I make will be mild steel 1/8 or so and it will probably still out last me with the bus only getting 10,00-12,000 miles a year when it's finished if it ever gets finished. Just a little food for thought guys.  | ||
| Jon W. Rating: N/A |
Some airplane exhaust systems are stainless steel. Some are inconel. I think the key to success is in how they are constructed, and not the material used. On my plane certain joints are slip joints to compensate for heating and uneven heating of the system. On my 8V92 one of the turbocharger inlet tubes has a "bellows" that will come and go as necessary Your stanless muffler will work like a charm if certain stress points are allowed to move. The bus exhaust temperatures are around 1100 degrees max if my pyros are accurate, but my EGT for the plane approaches 1700 degrees, so a stainless muffler is possible. This is a great example of the huge amount of engineering we rarely appreciate when we start thinking we can do a better job of designing a bus or motorhome. I have been humbled a lot. | ||
| Geoff (Geoff)
Rating: N/A |
I don't think it was the heat that cracked the stainless, it was probably the vibration. Can you weld up the cracks and reattach it with a short flex pipe? | ||
| Marc Bourget Rating: N/A |
Jon W. Well said! Nick, any possibility that you can post a picture of original installation and the present remains of the SS muffler? Maybe some post-mortem discussion could help you with your mild steel version, or maybe with a few changes you might consider SS once again??? Onward and Upward | ||
| Tim Hoskinson (Tdh37514151)
Rating: N/A |
HEY Nick you know their are many different types of stainless steel. depending on the amount of chromium and nickel it will change the ability to with stand flex. Your muffler if mounted as the original more or less hangs from one end where it is flange mounted to manifold. In this application the steel should have been of lessor chromium as used in most appications like exhaust. Hope you got your alternator going. Good luck Nick I'll see you again some time. Tim | ||
| captain ron (Captain_ron)
Rating: N/A |
My harley had a stainless steel header (super trapp) It has been welded 3 times It does not hold up to heat or vibration. on the upside it can be fixed flawlessly and returned to original condition. but who wants the head aches? | ||
| Marc Bourget Rating: N/A |
Hey Guys, Revisit Jon W's post. It not the what of heat and vibration but the how. If I pushed a softball against your chest with a 10 lb force it's quite different from a straight pin with 10 lb force. SS allows you to use thinner material because of it's strength and heat and corrosion resistance. But you can't expect even mild steel mufflers bolted directly to the exhaust manifold to survive those combinations of heat and vibration. I daresay that a mild steel muffler heavy enough to survive those forces would simply break the exhaust manifold. Allow for expansion and vibration and both styles will live a long time. Onward and Upward | ||
| niles steckbauer (Niles500)
Rating: N/A |
Marc - exactly - if you ever owned had a chevy BB 454 - you know how easy it is to crack the manifold - tick....tick....tick.... - Niles | ||
| Marc Bourget Rating: N/A |
Funny you mention that. I've had a 454 and the stock manifolds - they never cracked. Just gave one away to a friend for his 'Burb. Course, by giving away the "lucky" piece, my dog will get run over, wife will leave with the postman, I'll lose a testicle to cancer, . . . Ace will win the powerball lotto! [Good for him!] LOL!!! Got headers when they built up the 483 BB. That with the New Venture 5 sp makes it a pretty nice truck. | ||
| Two Dogs is my Hero Rating: N/A |
...wife will leave with the postman... and that's a bad thing? LOL | ||
| Nick Morris (Nick3751)
Rating: N/A |
Alright guys all the help/ideas you can give are apprieciated. I'm going to get the local high school ag shop to build me a new one, gives them something to do and it's cheaper for me (I don't have a shop down here yet). So here goes nothing with the pics; one is of the side the top is where it mounts to the manifold the bottom is the outlet and then the other pic is where the end WAS.   | ||
| James Maxwell (Jmaxwell)
Rating: N/A |
Is there any possibility of moving the muffler down along what is now the tailpipe route where you could work an expansion bellows (joint)into the manifold discharge. Perhaps all the way down to the bottom of the body with the outlet a straight out dump. Might involve a different configuration of inlet/outlet location on the new muffler. The damage appears to be purely vibration stress related IMHO and not heat. | ||
| Jim-Bob (Pd41044039)
Rating: N/A |
The stock dual steel mufflers on a 4104 have about 1" of inlet pipe worked into a flare that clamps directly to the manifolds. The outlet end connects to regular tailpipe which is fastened to the block with muffler clamps & small brackets. There is no expansion built into the design. That was the original design from 1953-1960 which has gone many many millions of miles on about 5400 4104s. Mine have been doing their thing for over 20 years. They are rusting out but not cracking. Jim-Bob | ||
| Tim Hoskinson (Tdh37514151)
Rating: N/A |
Nick think about the way the muffler on my parts 3751 bus was mounted. It was constructed of stainless but was remote mounted and had a flex between the manifold and the muffler. Also your original muffler should have had a lower bracket on the tail pipe end attached back to the engine similar to what Jim Bob is saying was on the 4104. Did you happen to do the same to your new muffler or was the bracket missing from the original so you didn't know it needed it. Tim | ||
| Brian (Bigbusguy)
Rating: N/A |
Just do away with the muffler and run pipes only , It may make a little more noise but no muffler problems. Brian 4905 Klamath Falls Oregon | ||
| Nick Morris (Nick3751)
Rating: N/A |
The only difference in this one and the original is there was a small piece on the tail pipe end that the clamp bolted through. It was like they didn't want the clamp to slip off so they ran the bolt through this piece. I can stop it from comming off so I don't figure I needed that but there were no other brackets on the whole deal. The muffler did fit into a bracket on the back of the block and a band went around it. With the smaller muffler the band no longer fit but I made a new one and had it pretty snug when I left. It's no where to be found now. As for the belows I've never seen something like that so I can say if I can do it or not. It would have to have the same method of attaching it that the muffler does (to the manifold). So I don't know how to put a piece of flex in there unless just a piece of pipe to the manifold and then flex to the muffler. I should have looked at Tim's when I was there but I thought I had this part done. If the consensus in it's the vibration not the heat I may try to patch this one and get it attached a little better. What do you guys think fix my original attacting point and fasten the tail pipe when it makes the bend from verticle to horizonal or do I need more than that? | ||
| Nick Morris (Nick3751)
Rating: N/A |
Here is the way the thing sits in the bus:  | ||
| Jon W. Rating: N/A |
Nick, If I were to guess the vibration contributes, but the primary cause would be the lack of compensation for the expansion of the parts when they are heated. That is not to say vibration is to be ignored. A part under stress such as when it expands and cannot move will be adversely affected when vibration is factored in. With vibration alone you can destroy almost anything if you have the right frequency. Don't believe anything I say unless you have verified it. I'm guessing. | ||
| Nick Morris (Nick3751)
Rating: N/A |
Alright so how do I build an air tight muffler with room for expantion? | ||
| Jon W. Rating: N/A |
I'm clueless when it comes to your particular application but I can express some generalities. I presume the muffler is attached to the frame. It will expand when heated and contract when cooling. Attach it so that can happen. That is why a typical set up is one rigid attachment and a second attachment with a means of movement such as a flexible support strap. Moving back to the engine you not only have to deal with expansion and contraction due to the heat in the exhaust pipe, but you have to deal with an engine that moves to a certain extent. Somewhere in the distance between the engine and the muffler the exhaust pipe needs to be able to expand and contract, as well as move or flex (that is where a bellows comes in) to compensate for all of this expected movement. I don't know if the exhaust comes from a turbo or from an exhaust manifold, but regardless there needs to be some consideration given to the differing expansion rate if different materials are used. As I said earlier the engineering to just add an exhaust system to a bus is indicative of just how difficult it is to try to improve on a factory engineered job. If it was easy there would be a whole lot of homebuilt RVs on the road. For a while I was involved in the design of production shipping skids for Cummins M11 engines. We designed a light weight skid of formed sheet metal to replace the structural channel skids they were using. The skid had to withstand a full range of fequencies of vibration as well as "G" forces in several directions. The sheet metal design withstood far more than the older structural steel design because it "gave" and it was less likely to vibrate itself or the engine apart. We literally spent months and built numerous prototypes before we had a product acceptable under all conditions. My hat is off to you if you are able to meet your objectives, which are very reasonable, but which require a lot of effort. Jon | ||
| Nick Morris (Nick3751)
Rating: N/A |
Most of the vibration will be caused from the road since the muffler is bolted to the manifold and then straped to the block. I'll let ya'll know how it turns out. | ||
| Jon W. Rating: N/A |
Nick, Do not forget the vibrations caused by the engine, the coach and its suspension, the tires, and the pulses of the exhaust. I'm sure I am forgetting a lot of potential sources, but one thing we learned was that if you find the right frequency you can disassemble almost anything. |