Ej25 Muffler

[Paul C]

G'day All
Ive got a problem with a muffler, stress cracks and baffles rattling around. Took it to the local exhaust shop but he wasn't interested in repairing it, he thinks it's too far gone. Anyone know of someone who manufactures or repairs one off mufflers like this one?
Cheers Paul

[RickE]

Come on fellas, surely one of you suby experts can help Paul out. This must have happened to someone before......surely!

[RossM]

you would think any muffler/exhaust shop would make one up!

[tonydenton]

my exhaust system was designed to be quiet. taking off from ROB'S place meant appeasing his cranky neighbours. but struth it is heavy . I am thinking along the lines of an ally one now and to hell with the noise as these type that paul has seem to be quiet enough. any ideas on an aluminium exhaust.
but yes ROSS is right any exhaust shop would be able.
PAUL , too much welding on that one now to do any good . too much weld too many times. need to start again and with some flex joints and springs and tie wires.

[mad max]

Flex joints, yes I learnt the hard way after having part of an ej25 manifold brake away and go through a prop. making a bush forced landing necessary. I have since made a two into one via flex joints and then through two flow throughs and a tail pipe right out the back like a car. Neighbours tell me I'm less noisey than lite planes. I found the modern exhuast pipe is hard to gass weld. Must have some anti corrosion mixture in the steel. I now use a stainless rod in an arch welder and do short bursts. Have since purchased an electronic welder. Yet to try it but believe it shall be a lot easier with its low DC output. I think the secret is in the 'pulse frequency' A good exhaust shop should make up anything you design but don't tell them it's aircraft of any sort as everyone is scared of liability. (American disease)

[mad max]

Fired up my EJ25 today to do some fine tuning and she was extra noisy on the RH side. Checked and there was a hole in the pipe near the engine. I thought I was smart and had wrapped about 8 months ago some fabric exhaust tape from Repco around the pipes near the engine to decrease radiated heat. Also thought it looked sexy. However it caused the pipes to rust out quickly from the outside in. Possibly due to getting wet in the rain? Anyway i'm not going to use that tape any more! Would be nice if one could purchase stainless pipe and mufflers. Stainless welds easy i found with a good ark welder and stainless rod and of course quite a bit of experience.

[Paul C]

Your right Tony, too many welds. It needs some flex in it.
Found a fella at a muffler shop to repair it, I needed a quick repair to get the gyro ready to fly to the nationals.
Spoke to a gyro builder and he makes up the same joints as the rotax exhausts, slip joints and springs, might have to learn how to weld stainless with the old Copper Mate 200 arc welder and make one up.

[mad max]

Yesterday I tried out my little electronic welder from BOC Gas ($240) with stainless rod. Definitely a little easier than the old AC welder. One must of course weld in very short zaps on thin material otherwise you're sure to burn holes. Learn at first on scrap material.

[chook]

Don't bother with the stainless tube that the exhaust people sell. I had to replace it all with the aluminium coated steel because the stainless cracked at the weld and bend points on my EA81 build even though I used a TIG welder and post welding heating to de stress the joints. I use the VERY loud Y method without a muffler which gives excellent flow and

breathing characteristics. I assume that the EJ Subaru series with the flat 4 configuration has the same expansion problems as the EA81 whereby as the crankcase and heads expand and contract so does the exhaust manifold which leads to the cracking. Never mind that they are running at 5000 rpm with the associated harmonics which really test out any metal structures attached to them.

Regards........Chook.