Author Topic: Muffler for model i.c. engine  (Read 1551 times)

Offline Brian Rupnow

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Re: Muffler for model i.c. engine
« Reply #15 on: August 24, 2018, 10:17:01 PM »
So--Here we are with the center parts all soldered together and the outer shell slid into place. The center consists of the two 5/16" o.d. tubes that extend out from each end plus the center plate with a bunch of holes drilled in it. I'm not going to show you the insides, because it is soooooooooo ugly. How ugly is it?--It's ugly enough that if it were a part that showed I would make it over again. However, that nice clean outer shell hides a lot of sin. Tomorrow I have the two endplates to make plus the flange which bolts to the engine.

Offline Brian Rupnow

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Re: Muffler for model i.c. engine
« Reply #16 on: August 25, 2018, 06:31:09 PM »
The new muffler is finished and installed on the engine. If you look on top of my ignition box you will see the old straight pipe setting in the lower left hand side of the picture. The new muffler turned out looking great. There was some really nasty blobby silver soldering inside, and of course the flat divider plate between the two tubes twisted and bent all to hell from the heat. Some quality time with a small body hammer and various pincer type tools got it sorted out to the point where it was good for functional but too nasty to show people. Next step will be to make a video to compare how loud the engine is now compared to what it sounded like with the straight pipe on it.

Offline Brian Rupnow

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Re: Muffler for model i.c. engine
« Reply #17 on: August 25, 2018, 06:56:11 PM »
And here we have a video of the engine running with a muffler on it. I think it is quieter than the video I posted earlier in this thread when it was running a simple straight pipe exhaust. Let me know what you think.---Brian
]https://www.youtube.com/watch?v=iggh3paQdMgl]
« Last Edit: August 25, 2018, 07:00:19 PM by Brian Rupnow »

Offline cfellows

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Re: Muffler for model i.c. engine
« Reply #18 on: August 25, 2018, 09:28:45 PM »
Sounds like a Briggs!

Chuck
So many projects, so little time...

Offline Brian Rupnow

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Re: Muffler for model i.c. engine
« Reply #19 on: August 25, 2018, 10:56:21 PM »
 Lets face it--we are generally happy just to see our engines run, and be able to rev up or idle down on demand. There IS a lot of mechanical noise from these small engines. I have removed the muffler and am doing some remedial work on the flange which attaches it to the engine. Although I did use a jig when I soldered the flange on, it was a crummy jig and the flange turned out quite crooked in respect to the muffler body. I was able to fully tighten the two top shcs, but not the bottom ones. I will show the new jig I am making to correct this issue, and then will repeat the sound test.---Brian 

Offline Brian Rupnow

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Re: Muffler for model i.c. engine
« Reply #20 on: August 26, 2018, 12:07:16 AM »
I have removed the flange from the muffler, made a new flange, and made a welding fixture to align the new flange properly with the muffler body. The four dark blue shcs are "sacrificial"--That is to say, they will end up silver soldered to the face of the flange--not on purpose, but unavoidable when soldering in such close proximity. The heads will be machined off after the flange is silver soldered to the muffler. Then the two pink/purple shcs will be removed and the green angle (with muffler and flange still attached) will be   pulled straight out of the blue fixture block. Then the dark blue shcs will be drilled out if necessary.

Online rklopp

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Re: Muffler for model i.c. engine
« Reply #21 on: August 26, 2018, 12:49:14 AM »
Here’s one of the mufflers I made for my six Upshur Twins. It is a scaled version of the muffler on my Breisch Hired Man hit-and-miss, which in turn is a scaled version of the muffler that was on the Wisconsin V-4 haybaler engine I played with as a kid. For scale, the thread on the Upshur muffler is 1/4-40.

A lot of hit-and-misses have that style of muffler.


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Offline Brian Rupnow

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Re: Muffler for model i.c. engine
« Reply #22 on: August 26, 2018, 01:14:42 AM »
Thank you, Rklopp--I have seen that type of muffler before. I'm not really certain of how much noise they actually muffle, but it must be some.---Brian

Offline Brian Rupnow

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Re: Muffler for model i.c. engine
« Reply #23 on: August 26, 2018, 05:49:41 PM »
I reworked the muffler flange, and re-soldered it using the welding fixture shown in the previous post. I got lucky with the four dark blue socket head cap screws--Three of them unscrewed and I only had to drill one out. The muffler is reinstalled, and it seals properly to the engine now. The noise level has dropped a bit more, but trust me---Ya wouldn't want to have to sleep in a room with this engine running beside your bed.---Brian
t=6s

Offline Admiral_dk

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Re: Muffler for model i.c. engine
« Reply #24 on: August 26, 2018, 09:00:31 PM »
That muffler is officially a success Brian  :praise2: