Hey all,

I'm having a difficult time keeping my muffler back-half from rotating, thus throwing out all the black gunk. Engine is a .46 Evolution on a Pulse XT. Anyways, whenever I've tried to tighten the nut down for the back half, it will never get tight. It will continue to spin, and the screw up front doesn't rotate at all. Someone at the field told me this was probably because the threads were stripped on the screw that runs between the two halves. They recommended putting on some washers in to act as spacers so I could get it to latch onto good threads. The problem is, this doesn't work either. I've tried putting a bunch of washers in, but there doesn't seem to be any good threads left or the nut itself is bad (is that even possible).

Any advice or instruction on what to try next?

Remove the original bolt that runs the length of the muffler. Drill it out and replace with a piece of all thread. Double nut at each end to hold the muffler in place.

Hope this helps

Ken

Hey Ken, those nuts look familiar. Ken used some locking nuts that I had sent to him. This method works real well.

Hey ken, that is a really good idea to have that safety wire on your muffler just incase it can get past the double bolts. If everyone did this nobody would ever loose the back half of their mufflers.

I learn somethinig here every single day!

LT-40

I started doing that after I bought my second muffler because I lost the back half of one. It's probably saved me 8 or 9 times in the last 6 years or so.



Bruce,
Yep, those are the locking nuts I got from you. Those are aviation grade nuts. For those that don't have access to that type of hardware just use a stardard nut and double it up.

Ken

Now you need some safety wire twisters, that's poor.[:'(]
http://www.harborfreight.com/cpi/cta...emnumber=45340
I keep this cheap set at home and my good set at work.

Well, since I don't work in the aviation field I keep a cheap set in my flight box as well as at home!!! [X(]

But lacing pliers are invaluable for keeping things on with lacing wire!!

Ken

On the Evolution muffler the bolt tightens into the outlet half and the nut is just a jam nut. Loose the nut and really tighten the bolt and tighten up the jam nut. Also if it came loose make sure you check the position of the drain slot in the baffle so it can drain accumilated oil in the muffler.

flynte


whoops...should have read whole thing......sounds like new bolt time.

My first OS 1.20 AX, have it on my Excelleron 90, was in the third or fourth flight when all of a sudden, the noise level increased several dB.

I landed it and saw that my brand new OS 1.20 AX had lost the rear section of the muffler. Boy, was I miffed.

And, with the size of our field, there was about a 2% chance that I would find the parts.... tall grass, brush, and so on.

Well, we walked the field, and right in the middle of the cross-runway was my muffler, baffle, bolt, o'ring, and nuts, all sitting there within a three foot radius!!!

Since I live very close to Atlantic City, it was time to visit the Casino's...

I got everything back but saw that the bolt was broken at the check-nut. I must have over-tightened it then after heating up and expanding, it simply was to much for the bolt and it parted at the nut. I replaced it with a lenght of 'all-thread' and ny-lock nuts, and used some red lock-tite and that was that.

DS.

Good call on double checking the position of the drain slot flynte. When I had my muffler apart, I didn't even realize that was there. I assume it should go toward the bottom?

Hi weeber24
The muffler is subject to tremendous vibrations. I have seen many people lose the muffler in the air, and then, sometimes, crash. I have almost zero problems now. I use automotive silicone adhesive sealent on everything on the muffler, including the gasketed joint between the engine and muffler, and the muffler halves. At the first sign of a leak in that area, I take everything apart and re-do it. I probably re-do it 1-2 times per year.