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Muffler Support Rod for PA18

FullThrottle

FRIEND
Kenai AK & Houston TX
Reference parts 15-17...I have an O-320 on my Super Cub, and prior to the restoration I didn't have this muffler support rod on my Super Cub. So the muffler shroud wiggles back and hits the firewall (it seems very stiff when you try to move it on the ground, but after landing noticed it was up against the firewall again). I tried tightening all the bolts, but it still wiggles. I found the stay rod and clamp assembly in the parts manual, and found that Atlee Dodge makes the PA18 muffler support for their hot rod muffler.

I was wondering if anyone had other solutions or had fabricated one, or experience using the Atlee Dodge support rod. I can't find the original parts using the part numbers online, so at this point it's either buy it from Atlee Dodge or fabricate something.

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Buy appropriate diameter clamps from Atlee. The just buy some 3/8” steel tube cut to length. Beat ends flat at proper orientation. Drill hole. Install


Sent from my iPhone using SuperCub.Org
 
What Mike said.

Atlee's clamps are good stuff and the rod is just a steel tube with flattened ends.

Web
 
clamps are easy to make also with some sheet steel, cut some strips, form around, round and 90 degree the ends, drill the holes, 1/4 inch i believe.
 
Make certain that at least one of the clamps is not tight. If they are both tight either the clamp or the rod will break. ​This brace serves two purposes. One is to help keep it from hitting the firewall and the other is to keep the shaking tailpipe vibrations from tearing out a nice crack in the muffler.
 
Is this part as necessary for he O-320 on the pa-12? I notice my pipe has the fitting for this but nothing is on there. I’m currently manufacturing new hardware for the vertical muffler support rod with springs that have become totally worthless due to improper rigging Nd and vibration.
 
Is this part as necessary for he O-320 on the pa-12? I notice my pipe has the fitting for this but nothing is on there. I’m currently manufacturing new hardware for the vertical muffler support rod with springs that have become totally worthless due to improper rigging Nd and vibration.
Any long unsupported pipe being subject to heat and vibration needs support to prevent cracking of where it is plugged in (muffler). Hot aircraft stainless steel exhaust system components are particularly susceptible to cracking. I do believe it is called for on the PA-12 as well. Doesn't the -12 also have support rods tying the pipe at the muffler to the engine mount with a spring on both sides? It's been a long time since I've looked at one.
 
Do the clamps that hold the exhaust pipes to the muffler have pins to keep the muffler from rotating? Sounds like the wrong muffler clamps item 20 to me.
 
Mine does have the clamps that fit everything together and those rods with springs are what I’m re-fabricating
 
So would you delete this from the O320 and just do the support to the tail pipe?
 
I would, they were used on the O-235 powered airplanes which leads me to believe there was a vibration with that engine possibly.
 
Mine does have the clamps that fit everything together and those rods with springs are what I’m re-fabricating
Do those clamps have the antirotation pins? You can see them welded to the clamp without removing it.
So would you delete this from the O320 and just do the support to the tail pipe?

I would, they were used on the O-235 powered airplanes which leads me to believe there was a vibration with that engine possibly.
If the exhaust is the same length from the cylinders to the muffler, I would continue to use the rods since they are supporting the weight of the muffler. Without them that weight is supported at the joint where the pipes from the two cylinders come together and/or at the cylinder itself. This would then place the stresses at that location. Not good.
 
Talked to me guru in Kodiak and he said definitely get a support from tail pipe to manifold and to keep the spring/rod support as bonus protection. So does anybody have pictures/measurements/Part numbers for the support we’re asking about on this thread?
 
So would you delete this from the O320 and just do the support to the tail pipe?

I would get rid of them and do it the same way every supercub does it with the stock exhaust and proper parts. It seems to work well. I would not like the possible vibration path from the exhaust through the tubes to the mount to the firewall etc bypassing the rubber isolation mounts. I really don't like vibrations. Just a thought
 
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Mine has it from the pipe to the midpoint on the tailpipe. I think Pierce took this pic.

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