Hi,

I have a Bisson pitts muffler that I'm using with my Evolution 46. I'm using the same screws that I used with the Evolution muffler and they tighten just fine, but they keep coming loose. Any hints? High temperature Loctite maybe?

Thanks

I loctite my muffler screws and haven't had any problems with them

Thanks

Do you use the high temp kind or the regular? The reason I ask is because folks tell me that the regular loctite won't stand the heat.

G'day Mate,
Sounds like a vibration issue, balance your prop, I have a Bisson Pitts Muffler on my OS 160FX & have never had a problem with it coming loose, I don't use any gaskets or locktight, But all my props are balanced using a Du-bro balancer. It will also save a lot of radio & fuel foaming problems, if the vibation level is kept to a minimum.

iv had the same problem with my heli......i epoxyd my muffler straight to the engine with out the gasget....and thred lock the bolts...the muffler will never come loos with that dun when u want to take the muffler off just take the bolts out and giv it a tap on the bench and it will come straight off again

Use a big flat washer then a lock washer on top of that on both bolts. You can also change out the bolts to a better brand. I have found that between lockwashers and good grade bolts, I do no use locktite.

As was mentioned, locktite will not stand up to the heat and the high temp stuff will make it impossible to remove the bolts later on

I make sure that the threads are clean (no fuel residue on them) and cover the threads with silicone. I let it sit overnight to cure completly before running the engine. The silicone hangs on and is vibration resistant. [8D]

Thanks

That's a good idea. I imagine getting the residue off the screws is fairly easy, but any tips on cleaning out the screw holes?

One way to clean out the screw holes in a muffler or crankcase is to blow them out with carb cleaner from an auto parts store, then do what you can with bits of paper towls. I generally find that a good shot of the cleaner will blast out most of the oil and junk. I'm sure there are other ways to do it though.

Thanks. Another good idea.

And yet another question. Speaking of going to the auto parts store, can I use gasket maker to use to make a muffler gasket instead of buying a replacement ready made one?

dunno, but personally I toss out all those goofy muffler gaskets. All they do is ensure a market for replacement mufflers . Seriously, the gaskets just compress and allow the muffler to get loose. The machine work on most mufflers and crankcases that I've seen is smooth enough that a straight metal-to-metal joint that is tightened down seems to work just fine for me. YMMV though

Yeah, I pretty much have to use the gaskets on my two Evolution engines or else I get leakage.

J-B Weld is your friend.

A little judiciously used does the trick.

I guess I should have also mentioned that I also use the silicone as a gasket seal. Just make sure that it has cured completly prior to running the engine. [8D]

I would think JB Weld would never let you take it off again unless you use a hammer and chisel. It's designed to withstand more temp than we are dealing with on a glow engine

I always use a little Locktite , high temp, or med strength works fine.
Don't over tightened the bolts, they are steel, the muffler is aluminum and strips very easily.

Actually J-B weld is not permanent.

Nor as strong as say Epoxy AFAIK.

I've had no problems removing components that have been J-B welded.

It was suggested here that I use J-B weld on a muffler exhaust that swiveled in flight thanks to the heat... this worked perfectly.

The components require a bit more strength to turn or dislodge much like Locktite.

However J-B weld does not break down like Locktite does at high temperatures, so it's better suited for the engine applications.

Thunderchicken, I would think the threads on your Evolution .46 are metric. The threads on the Bisson are SAE unless I'm mistaken. I have several Bissons in service and I think I remember use SAE screws. If you are using a smaller metric screw in place of the SAE threaded hole in the muffler, no wonder it's coming loose.
I just checked and Bisson does drill and tap their mufflers for the screw used with the stock muffler. I must have been thinking of Slimline.