Loose muffler

[Brian4301]

OK.....little problem. I put the damn thing on (red). 2 min of hovering and the muffler is loose. My local tech adv. to put a nut on the back side and that fixes it. My bolts are to short, so I cleaned again, reassembled with red (everywhere) and waiting for 24hr to dry.

Going to heat up then tighten some more. Other than the added nut is there another fix?

[gehrbox]

Originally Posted by Brian4301

OK.....little problem. I put the damn thing on (red). 2 min of hovering and the muffler is loose. My local tech adv. to put a nut on the back side and that fixes it. My bolts are to short, so I cleaned again, reassembled with red (everywhere) and waiting for 24hr to dry.

Going to heat up then tighten some more. Other than the added nut is there another fix?

I've read that using red or blue locktite on an exhaust can act as a lubricant because the exhaust heat liquifies the locktite.

I have tried a number of methods on planks that had a tendency to loosen after a flight. The best solution is to run the motor, get it up to temp and then retorque the muffler. Has worked on several engines for me. No locktite was applied.

It's possible that the bolt holes in the muffler have been stretched from running loose and may not be able to hold tight.

[fastflyer20]

I agree with the tech, get longer bolts, use nuts and forget about it.

[drdrums]

+1 on NOT using loctite. The stuff starts melting past 300 degrees or so, regardless of color.

My muffler became loose last time out, as I forgot to retighten after a rebuild (no loctite, though). Previously, the first few flights, when I did retighten, it never came loose.

As a bit of an experiment and on a recommendation from the local expert at my LHS, I've added a bit of red RTV (hi-temp silicone gasket compound, good past 500 deg.) to both the gasket and on the threads as a locking compound. We'll see how it goes - it's supposed to work...

[fastflyer20]

RTV on threads is OK, as a gasket sealer, it is notorious for causing glow plug problems, more so on pumped engines.

I tried a bunch of different measures, in the end, lock nuts were the simplest and worked every time

[Brian4301]

Yep....Nuts & Bolts

Thanks

[pilot4fn]

Originally Posted by Brian4301

Yep....Nuts & Bolts

Thanks

With Align 50-H engine and original muffler I use Align gasket, a bit longer bolts, star washers with lock nuts.
When firts tankful is done after rebuild I re-tighten the muffler and it's good to go a gallon or so. Regardless, I check the tightness of muffler just about every flight day by trying to move it up-down by hand (not forcefully).
Never problems with this process.

[raylepper]

+1. The aluminum threads will strip easily. Nylok nuts and maybe a little filing to make a flat for them to sit on. Problem solved.

[Brian4301]

Longer bolts, nylon lock nuts. I burned one tank and snugged down a little more and all seems well.

The exhaust gets crazy hot, does that cause problems with the nylon in the lock nuts melting?

Just an observation

[nitro-pro]

+1 on the longer bolts and lock nuts, but if you want a "one time and forget it" soulution to leaks where the muffler meets the engine, go to your local Ace Hardware and pick up this putty called PC-Fahrenheit, it's an epoxy putty, clean both surfaces well with alcohol, knead the putty and make a gasket with it by putting a small amount on your finger and sliding it down over the edge of the mating surface forming a thin flat layer all the way around, then install the muffler and let it sit 24 hours. I had a problem sealing my Hattori on my 600 no matter how tight I made it, it stll leaked and this worked extremely well and have yet to have even the slightest leak, I had no more issues and even easier time tuning due to the nicely sealed system. Good luck, hope that helps! I have included a link below
http://pcepoxy.com/our-products/putt...fahrenheit.php

[fastflyer20]

The nylon melting does not effect it staying tight. Since the pipe mount is threaded, it is the equivalent of using two nuts tightened together, like jam nuts.

[raylepper]

Melting temp of nylon is over 450 degrees F. Not sure if NYLOK nuts actually have nylon in them. But mine have never melted. Though I do try to keep my engine below 450F

[Alignnitro]

Speaking of exhaust, on my 2 flight of the day { mind you the exhaust has 3 previous flights on it and is new } my motor went from running smooth to running like hell... I landed right away and noticed my exhausts was loose and hanging off... I couldnt believe it. I

I grabbed the driver and tried to tighten it up and the threads were gone inside the exhaust. What is up with this. I did not overtighten this exhaust at all.. I am very good about not doing so as I work on Harleys and learned that lesson at a young age. I am totally clueless to why this happened.. I googled this and have seen folks talk about the metal being really soft on these exhaust.. Can someone help me out here to why, how, and what the fix it ?? Its a funtech pipe { B 320 i think ..... Its the newer funtech for the 55.} Do they warranty this at all.. Its got 5 flight on it....


I was so happy because yesterday was my maiden of the beast x !! The bird went straight up without one issue.. Tail held very well and it felt awesome for just being installed and no tuning or nothing !! I see why everyone loves it so much ... But my excitment was cut short after one tank !! lol

[Brian4301]

Same problem with my Align muffler.

Nuts & Bolts, no problems since

[Alignnitro]

Really suck monkey butt. I guess it's cheap metal that causes this or maybe the fact that the threads are so fine and then the heat and vibrations cause them to let go. Whatever it is seems to be a major issue because it's all over if u google it. I was surprised to see so many people having same issues on several pipes. The companies making these pipes need to step it up and fix this issue

[fastone93]

Originally Posted by raylepper

Melting temp of nylon is over 450 degrees F. Not sure if NYLOK nuts actually have nylon in them. But mine have never melted. Though I do try to keep my engine below 450F

your pipe temp will be much higher than your head temp... ask any full scale pilot that flies a plane with cylinder head and exhaust gas temp. gauges. And yes the nylon will melt. This idea works great as long as you still have threads in the pipe to use as a jam nut, otherwise it will loosen by itself...

there are lots of great pipes out there performance wise, but Outrage is the only company that I know of that has steel inserts to attach the pipe. I wish that these other companies would get their heads out of their %$#^% and follow suit. It works awesome!

[Alignnitro]

Can someone give me the best fix. I'm fixing to just buy another pipe but it sucks because this Pipe has like 5 flights on it. I can't believe it did this !! Almost wanna call Heliproz and see what they say but I know it wouldn't be any good and it also isn't a problem of theirs.

I guess my worry is that itll do it again with a new pipe.

I was thinking of taking it to the machine shop at work and having the guy I work with put a recess in the muffler so I can slide to bolt through that end, then use lock nuts on the motor side. This was a though and I haven't looked at the muffler or motor yet to see if this will work. May not be able to get bolt in straight idk.

The threads are totally gone so I doubt a helicoil will work.

[raylepper]

Originally Posted by fastone93

your pipe temp will be much higher than your head temp... ask any full scale pilot that flies a plane with cylinder head and exhaust gas temp. gauges. And yes the nylon will melt. This idea works great as long as you still have threads in the pipe to use as a jam nut, otherwise it will loosen by itself...

I respectfully disagree on two points. I don't think our pipes reach over 450F and I have used Nylok nuts on my OS50 and 55 pipes where the internal threads are gone. They stay tight. Maybe I'm just lucky. My crash frequency would say I'm not, though. Having said that, I could certainly be wrong. Maybe somebody can use a temp gun this weekend and get the temp of the motor and the pipe. Would be interesting.

[Stevendavis]

Originally Posted by Alignnitro

Can someone give me the best fix. I'm fixing to just buy another pipe but it sucks because this Pipe has like 5 flights on it. I can't believe it did this !! Almost wanna call Heliproz and see what they say but I know it wouldn't be any good and it also isn't a problem of theirs.

I guess my worry is that itll do it again with a new pipe.

I was thinking of taking it to the machine shop at work and having the guy I work with put a recess in the muffler so I can slide to bolt through that end, then use lock nuts on the motor side. This was a though and I haven't looked at the muffler or motor yet to see if this will work. May not be able to get bolt in straight idk.

The threads are totally gone so I doubt a helicoil will work.

I had to buy a box of extra long bolts when mine stripped out. I've got a few extra if you need them.

[Alignnitro]

I went and got some 40mm and 50mm long. I got some nuts and lock nuts. I've seen some say the lock nuts will melt. Idk if this is true or not. I guess I could use double Nuts to lock the together


When i hold the nuts up to the exhaust it looks like it isn't gonna sit flush because of the round exhaust flange. What did u do there. Did u just out them on and tighten it up or did u file or grind it out to be flatter ?