Cox Mufflers with Snout, GONE?

happydad Thu Sep 03, 2020 11:30 pm

Well, here I am again tinkering again. Thanks to to another FORUM member I am the proud owner of a Cox Muffler with a Snout, you know, the thing that sticks out to the right, or left and directs the smoke, gas, and CRUD away from the engine and mostly the plane. Why did Cox do away with the Concept, or was it too expensive to add a small tube to the side of the main muffler.

So I decided to see if I could do this myself. Where I used to work 20 years ago we made HF, 2 to 30MHz, broadband Radio Equipment for 3rd world countries and I had used a brass tube similar to that on the snout of the old Cox Muffler. I have beed cleaning out the garage for various reasons, made $$ on 2 different OLD video games for ATARI 400, 800 Computer Systems, and I pretty much new about where the brass tubes were. I dug out a few different sizes, figured out the best one and sat down in a hot garage and came up with this, first the part.

brass tube

top side view 1

bottom side view 1

top side view 2

the outside diameter of the brass tube is about 1/4inch, so it is a little larger than the original Cox Muffler. I am trying to flatten the brass against the aluminum muffler, then use a hard epoxy to hold the tube against the muffler and seal it so no gasses leak and back up inside the muffler.

So what do you guys think of my idea? I have several of the brass tubes if you are interested and the manufactures part number and address.

happydad. RC Plane

**Cribbs74** Fri Sep 04, 2020 5:44 am

The discharge tube is actually a later addition. The original 1960’s QZ’s had no tube... so you probably have an early version that are kinda hard to find.

getback Fri Sep 04, 2020 5:52 am

I don't think the epoxy will hold , can u solder it ? Small Cox Logo

happydad Fri Sep 04, 2020 5:59 am

getback wrote:I don't think the epoxy will hold , can u solder it ?

getback: not to aluminum, very easily. Maybe with a spot welder, a small one. I will try the epoxy for now. They used to make an epoxy with little particles of metal or silver in it. Can’t remember what it was called. When I was in Japan some of the slot car guys used to use it on the motor armatures to cool them better.

Those were the days. Young and stupid, and all alone in Japan.

Happydad Jeep

sosam117 Fri Sep 04, 2020 7:27 am

happydad wrote:
getback wrote:I don't think the epoxy will hold , can u solder it ?

getback: not to aluminum, very easily. Maybe with a spot welder, a small one. I will try the epoxy for now. They used to make an epoxy with little particles of metal or silver in it. Can’t remember what it was called. When I was in Japan some of the slot car guys used to use it on the motor armatures to cool them better.

Those were the days. Young and stupid, and all alone in Japan.

Happydad

Happydad,
Try using JB Weld.
I have used it on some old Aurora Mills engine crank cases. and on an O.S. carburetor and has held up for a few years.
Usually got the JB Weld at an auto parts store.

Here is my version of an extension:
I used a small section of copper tubing ( left over from tubing for the ice maker).
Using a 5mm tap and die, I made some threads on the copper tubing and tapped the Cox muffler section.
After threading the parts together, I used a small amount of JB Weld on the threads inside the muffler ring.

getback Fri Sep 04, 2020 7:40 am

Thats cool , is the lip inside the muffler housing already there for tapping or did you make that also ? Huh...

aspeed Fri Sep 04, 2020 9:31 am

I think that is just a nut inside. Too bad a big pop rivet gun will not fit inside the muffler. It almost looks like the 3/16" rivet would work, and then the flare would hold it in. Some of those are aluminum too. I made something like that for a different motor that needed to have a larger hole. AP .15. Just threaded both the muffler and the insert. It stayed on so far. The pressure tap has unscrewed though. Another way to get the goop away is to just punch a hole in some silicone tubing and push the cylinder through it. Ace used to sell those.

**Cribbs74** Fri Sep 04, 2020 9:48 am

At second glance I have no idea what you have there. There are no cutouts whatsoever in that muffler.

sosam117 Fri Sep 04, 2020 12:57 pm

getback wrote:Thats cool , is the lip inside the muffler housing already there for tapping or did you make that also ?

There is no lip inside the muffler housing. I just drilled out the hole for the 5mm tap and tapped the hole.
The wall of the muffler housing is thin, that is why I used a metric tap (more threads per mm (inch).
What looks like a lip is the JB weld (epoxy) and a "C" clip clipped onto the threads ( it looks like a nut).

Oldenginerod Fri Sep 04, 2020 6:09 pm

This type of muffler with the plastic upper plate doesn't need an outlet as the upper plate flexes under exhaust pressure allowing exhaust gasses to escape. The ones with the spring clip around them are designed to lessen the restriction by opening up the exhaust when quietness is not required, and also allows the engine to be primed.

happydad Sun Sep 06, 2020 3:27 am

Oldenginerod wrote:This type of muffler with the plastic upper plate doesn't need an outlet as the upper plate flexes under exhaust pressure allowing exhaust gasses to escape. The ones with the spring clip around them are designed to lessen the restriction by opening up the exhaust when quietness is not required, and also allows the engine to be primed.

I tried the JB Instant Weld last night, Saturday, but it wasn’t completely hardened, I will take some pics and post later tomorrow.
>>>>edited 9-6-2020 at 3:45p.m. PST.

view 2

I still need to clean up and add more JB. Tomorrow.
>>>>>>>edit completed

Record setting temperature today at 113 for my town. It was still 93F when wife went to bed hours ago. It is still 85F outside at 1:25a.m. PST.

Happydad. RC Plane

sosam117 Sun Sep 06, 2020 8:40 am

happydad wrote:
Oldenginerod wrote:This type of muffler with the plastic upper plate doesn't need an outlet as the upper plate flexes under exhaust pressure allowing exhaust gasses to escape. The ones with the spring clip around them are designed to lessen the restriction by opening up the exhaust when quietness is not required, and also allows the engine to be primed.

I tried the JB Instant Weld last night, Saturday, but it wasn’t completely hardened, I will take some pics and post later tomorrow.

Record setting temperature today at 113 for my town. It was still 93F when wife went to bed hours ago. It is still 85F outside at 1:25a.m. PST.

Happydad.

Happdad,
It usually takes at least 24 hours for the JB Weld to harden up.
It may take longer with the high heat and humidity?

By the way, The muffler I have does not have a "plastic" upper plate.
It is spring steel and it seals tightly around the cylinder and only flexes downward to make a good and tight seal when the cylinder is screwed to the crank case..

Mike1484 Sun Sep 06, 2020 11:52 am

How about a spent .22 shell and some high temperature silicon RTV ?

Mike1484

fredvon4 Sun Sep 06, 2020 1:12 pm

J-B Weld

is The Original Cold Weld two-part epoxy system that provides strong, lasting repairs to metal and multiple surfaces. Mixed at a ratio of 1:1, it forms a permanent bond and can be shaped, tapped, filed, sanded and drilled after curing. At room temperature, J-B Weld

sets in 4-6 hours to a dark grey color. A full cure is reached in 15-24 hours. J-B Weld

has a tensile strength of 5020 PSI and sets to a hard bond overnight. It can withstand temperatures up to 550ºF when fully cured.

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Cox Mufflers with Snout, GONE?

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Not to Aluminum.

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added pictures

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