[Hughes500E]

Ok guys, started to work on the Extra and again I see my muffler has come loose. I have a wrap around inverted pitts style on a Brison 3.2
Any ideas as to how I can keep this sucker tight?

[Hughes500E]

Well the JB weld gasket is of no more. Andrew knew it wouldn't last though
Looks like the bolts I used tightened up against the Jb Weld but once all of it disintegrated it left the muffler loose, bolts are bottomed out.
I'm going to make a new aluminum gasket and use some spray gasket adhesive.
Unless someone can give me a better procedure?
Many guys thought it was a twin when I started it. It is not heavy on the vibration. The engine is not soft mounted, it is on aluminum stand offs. Something has to work well

[Bob Hudson]

Take the muffler off the engine

Forget about using gaskets !!

Clean the mating surfaces of the both the muffler and the exhaust port real well.

If your muffler bolts are not socket head cap screws throw them away and replace them with socket head cap screws

Use the RED high temp silicone ( comes in a gold colored tube - Canadian Tire or Home Depot )

Spread a thin smear on the exhaust flange of the motor. ( this will be the gasket )

Rub a thin smear on the threads of your muffler bolts. ( this acts as loctite, but is better for this use)

Install the muffler and tighten the bolts as tight as you can.

Let this sit to cure for not less than 12 , prefferably 24 hours, before running the motor.

It won't come loose !!

[AJCoholic]

thats what Jim Bisson recommends also, has worked for me with most engines...

I have one engine, a Brison 4.2, that will NOT keep the muffler on. I resorted to strapping it on with a metal hose clamp and that seems to keep it tight enough for the bolts not to loosen up.

But thats an exception...

[Bob Hudson]

By the way, I just took another look at your picture.

Keep that gas line AWAY FROM the muffler.

Bob

[Kevin McGrath]

What Bob Hudson says with emphasis on throwing away normal gaskets.
I prefer Permatex Ultra Copper Hi Temp gasket maker.
In tight situations like yours I have resorted to grinding down the sides of a self locking nut until I could get it into the space and get the allen bolt started into it.You may find dispensing with the gasket will allow the allen bolts to hold on their own ,but dont use too much beef when tightening or you will strip the threads on the body of the engine.

[Hughes500E]

I'll try it with the silicone. I have some Utra copper that I can use.
The fuel line in my picture, I used it as a wire protector. Good tip though!
Fuel line is on the other side

[bigguy]

Just A question :

Has anyone thought of lockwiring bolts.That might not work in this situaton but we do this on full size all the time.Vibration has always been a problem and this method has been used since the days of the barnstormer.

Also steel bolts heat up slower than aluminum casts which causes the thread friction to virtually disappear and you loose the tension on the bolt.I have in the past elected to use helcoil's and solved some of my biggest problems with muffler bolts.I have been doing this since my motocross days. Mind you helicoils are not cheap unless you have access to some.

here is a link to help:

http://www.ultralightnews.com/pilots...safetywire.htm

http://www.tpub.com/content/aviation.../14014_115.htm

[Guest]

As Bigguy says use Allen head bolts and drill the heads for safety wire and once the bolts are tight using Bobs suggestion with the red or copper gasket maker on the mating surfaces as well as the bolts then properly safety wire the bolts as an added precaution.

Dennis

[AJCoholic]

The only problem, with bolt heads that are 3/4" deep in a muffler you cant get a wire in there...?