Dsegal

When I purchased a Norvel .074 engine I was delighted to see that the muffler was secured with two screws. But on the second day of operating it on a test stand I was startled when the rear section of the muffler popped off and flew downwind. Only a bit of friction with the O-ring secures this piece. Will I have to wire this on? Has anyone else had this problem?

Dave Segal

wild fred

My Feedback: (3)

wow! that's the first I've heard of that on an 074! You might email sig, they are a good company, see what they say. they just might send a new one!

Edwin

My Feedback: (2)

Never happens on mine. I wondered about that, had my doubts. But it seems to be on pretty good.
Edwin

Bipe Flyer

I had that happen on one of my .074s during break-in on the test stand. The muffler expanded as it warmed up and allowed the end to pop off. I drilled a small hole and used a small screw to secure it. I've also done this on .061 mufflers when they get older and loosen up a bit.

I've attached a picture. Sorry if it's hard to see, I had to peek in through the cowl.

Dsegal

Thanks for the suggestion Bipe Flyer. I will contact Sig tomorrow to see what they say. But your idea will be useful if nothing else comes up. What size screw did you use? Was it a self-tapping screw?

And BTW, how did you take that nice closeup?

Dave Segal

AndyW

My Feedback: (1)

I've never had the rear end of any .074 muffler come off. I don't believe that it was intended that the O-Ring is supposed to be the only thing holding it on. If your tighten the rear screw sufficiently, the back end ought not to fall off. Just try tightening your screws. Works for me.

Bipe Flyer

I used a #0 self tapping screw. I find it especially handy with the .061 mufflers as it prevents them from rotating in flight.

Dsegal

I just called Sig tech support. They said that tightening the muffler retaining screws pinches the muffler end to hold it in place. I just tried this and it seems fairly tight. But I may add a little loop of wire to be sure during test flights.


Dave Segal

Dsegal

I just had a "sticker shock". The .074 muffler assembly does appear on the Sig web site with the other Norvel mufflers. So out of curiosity I contacted them by email and asked about the availability of the muffler assembly. They have them in stock and the price is $17.99 plus shipping!

Dave Segal

AndyW

My Feedback: (1)

Dave,

Don't feel bad. I like to modify my .061s to take a bolt on muffler so I ordered 5 of them without even asking the price. Keep in mind that 17.99 US dollars is 27.00 Canadian dollars. Along with freight, tax, customs, the bill was over 160.00 dollars. That was a couple of years ago and I've found use for all of them but still.