Cracked Muffler 912. Suggestions?
in 912 / 914 Technical Questions
11 years ago
We have on our 2004 V-Fun Skyranger what I believe, from looking at diagrams on the Rotax parts vendors sites,
http://www.cps-parts.com/catalog/rtxpages/912914muffler.php
is a standard Rotax 912 exhaust system.
So first I’d like to confirm that this is a Rotax part, not a Skyranger (BestOff, the maker of Skyranger kits) part?
On a flight yesterday we heard a slight change in engine sound and got a little smell of exhaust fumes in the cockpit. Was pretty sure we’d developed an exhaust leak.
Opened the vents, and since all gauges were behaving, no other dangerous sounds, and it wasn’t getting worse (and since nearby landing options all had some undesirable features) proceeded the hour to our home field without incident… if with a little nervousness looking for emergency landing sites.
On landing we discovered a small crack about 1 millimeter wide and 10 millimeters long in the muffler right at the base of collar that fits to one of the four incoming header tubes.
Since then the crack widened to the point where the collar that the header inserts into the muffler has completely separated from the muffler by about 2 millimeter. See pictures.
If the muffler is a standard Rotax part we can of course order the part and replace it.
On discovering (a) the whole exhaust system is stainless steel, and with at least a bit of shock that (b) the stock muffler at CPS (and presumably other Rotax parts sellers) is about $1000 US, want to explore what alternatives for repair or replacement might exist.
#We could remove the muffler and take it to someone qualified to weld stainless and repair it.
# As perhaps a temporary repair we could repair/plug it with JB high heat putty which they specifically recommend (in areas where the continuous temperature is less than 450º F) for exhaust systems?
-------------
http://www.jbweld.com/product/j-b-highheat/
Temperature Resistant Epoxy Putty
Strength 800 PSI at Room Temp. 600 PSI at 400ºF
Set Time 1 Hour, Functional Cure 8 Hours, Dries Machine Grey
Great For: Exhaust Manifolds, Tail Pipes, Mufflers
-------------
Seem like that one option might be in the category of “worth a try” especially if testing in local air flights (as contrasted to trying to fly the Atlantic). My concern with even trying it includes the possibility that if we got that stuff on the crack it could interfere with latter doing a real proper weld repair (I sent an email to JB to hear their answer to that.) But if we decide to get a new muffler, might not hurt to try while waiting for the parts to arrive?
# I see at
http://www.rotax912exhaust.com/index.html
a Czech company making a complete stainless steel exhaust system for 912. Emailed them. Price is a fraction of the Rotax part -- the complete system is about $550 US including shipping. Anyone know anything about that as an alternative? According to their site it appears that their exhaust is used on at least some CT’s.
(“Airplanes with our Rotax 912 exhaust system:
SOVA, PEGASS, EUROSTAR, SAMBA, LAMBADA, KOYOTE, SWING, TEXAN, ZEPHYR, CT 2, CH 601, CH 701, TL 2000 – STING, ALEGRO, SAVAGE”)
# Thought I’d seen discussed here a cabin heater system based on a shroud around the muffler. Maybe even some here using it already. IIRR it involved replacing the whole muffler, or maybe the whole exhaust system, so at the time I first heard of it I ruled it out as I couldn’t see my way to replacing a whole “perfectly good” (or so I thought) exhaust or muffler to add a cockpit heat source. But if we’re looking at replacing the muffler might a an opportunity to do that. Anybody direct me to THAT product? Any experience using it?
Finally, I’m curious if anyone has seen or heard of a similar mode of muffler failure?
The engine is a 1999 Rotax 912UL with approximately 800 hours on it.
This SEEMS to me a premature failure. Something that IMO should be rare and/or perhaps even reflect, as they say, “product manufacture defect.“ Any speculation of possible causes (if only so we don’t put a new one on and in 800 hours duplicate the failure?) Given that in the pictures (which I’ll try to attach) you’ll see that after the attachment tube fully separated from the muffler it offset itself a bit out of line with the header entering, it appears that the header was tweaked a bit to force it to fit…. putting sideways pressure on the fitting.
Al
P.S., I see I double posted this. Will delete the other if I can.
Also:
Found this:
CKT Engineering manufacture a stainless steel exhaust and heater muffler for 912's
Here is the link:
www.cktengineering.com
Any feedback on THAT company's system?
http://www.cps-parts.com/catalog/rtxpages/912914muffler.php
is a standard Rotax 912 exhaust system.
So first I’d like to confirm that this is a Rotax part, not a Skyranger (BestOff, the maker of Skyranger kits) part?
On a flight yesterday we heard a slight change in engine sound and got a little smell of exhaust fumes in the cockpit. Was pretty sure we’d developed an exhaust leak.
Opened the vents, and since all gauges were behaving, no other dangerous sounds, and it wasn’t getting worse (and since nearby landing options all had some undesirable features) proceeded the hour to our home field without incident… if with a little nervousness looking for emergency landing sites.
On landing we discovered a small crack about 1 millimeter wide and 10 millimeters long in the muffler right at the base of collar that fits to one of the four incoming header tubes.
Since then the crack widened to the point where the collar that the header inserts into the muffler has completely separated from the muffler by about 2 millimeter. See pictures.
If the muffler is a standard Rotax part we can of course order the part and replace it.
On discovering (a) the whole exhaust system is stainless steel, and with at least a bit of shock that (b) the stock muffler at CPS (and presumably other Rotax parts sellers) is about $1000 US, want to explore what alternatives for repair or replacement might exist.
#We could remove the muffler and take it to someone qualified to weld stainless and repair it.
# As perhaps a temporary repair we could repair/plug it with JB high heat putty which they specifically recommend (in areas where the continuous temperature is less than 450º F) for exhaust systems?
-------------
http://www.jbweld.com/product/j-b-highheat/
Temperature Resistant Epoxy Putty
Strength 800 PSI at Room Temp. 600 PSI at 400ºF
Set Time 1 Hour, Functional Cure 8 Hours, Dries Machine Grey
Great For: Exhaust Manifolds, Tail Pipes, Mufflers
-------------
Seem like that one option might be in the category of “worth a try” especially if testing in local air flights (as contrasted to trying to fly the Atlantic). My concern with even trying it includes the possibility that if we got that stuff on the crack it could interfere with latter doing a real proper weld repair (I sent an email to JB to hear their answer to that.) But if we decide to get a new muffler, might not hurt to try while waiting for the parts to arrive?
# I see at
http://www.rotax912exhaust.com/index.html
a Czech company making a complete stainless steel exhaust system for 912. Emailed them. Price is a fraction of the Rotax part -- the complete system is about $550 US including shipping. Anyone know anything about that as an alternative? According to their site it appears that their exhaust is used on at least some CT’s.
(“Airplanes with our Rotax 912 exhaust system:
SOVA, PEGASS, EUROSTAR, SAMBA, LAMBADA, KOYOTE, SWING, TEXAN, ZEPHYR, CT 2, CH 601, CH 701, TL 2000 – STING, ALEGRO, SAVAGE”)
# Thought I’d seen discussed here a cabin heater system based on a shroud around the muffler. Maybe even some here using it already. IIRR it involved replacing the whole muffler, or maybe the whole exhaust system, so at the time I first heard of it I ruled it out as I couldn’t see my way to replacing a whole “perfectly good” (or so I thought) exhaust or muffler to add a cockpit heat source. But if we’re looking at replacing the muffler might a an opportunity to do that. Anybody direct me to THAT product? Any experience using it?
Finally, I’m curious if anyone has seen or heard of a similar mode of muffler failure?
The engine is a 1999 Rotax 912UL with approximately 800 hours on it.
This SEEMS to me a premature failure. Something that IMO should be rare and/or perhaps even reflect, as they say, “product manufacture defect.“ Any speculation of possible causes (if only so we don’t put a new one on and in 800 hours duplicate the failure?) Given that in the pictures (which I’ll try to attach) you’ll see that after the attachment tube fully separated from the muffler it offset itself a bit out of line with the header entering, it appears that the header was tweaked a bit to force it to fit…. putting sideways pressure on the fitting.
Al
P.S., I see I double posted this. Will delete the other if I can.
Also:
Found this:
CKT Engineering manufacture a stainless steel exhaust and heater muffler for 912's
Here is the link:
www.cktengineering.com
Any feedback on THAT company's system?
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