Exhaust Issue

[SC3CM]

Hoping I cab get some info from people who know this stuff better than I do!
PA-12 with an O320 (150 hp)
Post flight inspection after my last flight I noticed a broken exhaust stand. Ok. Need to get that fixed.
Then noticed the CO detector was really dark. Certainly not good. I don't want to fly it to my regular mechanic, there is another on my field who does great work just doesn't do cubs all the time so feel the engine/exhaust is a non issue and he'll do a great job.

He found an exhaust leak off the #3 cylinder, a blown gasket on #3, leaks on both sides of the exhaust stacks where manifold goes into the muffler.

He suggests dropping the exhaust and thoroughly inspecting it, re-doing the gaskets, and sealing with hylomar. He said that may become a yearly deal.

Is there anything that people here think might be logical to do at the same time, or other questions i should ask?

I have not noticed any engine/power/performance issues. Engine has 1300 hours on it and gets 100+ a year now.


Rene

 

[jgerard]

Yup you'll find the older it gets and the more things wear the more often you end up fixing things like that. Exh gaskets start to leak which blows super hot gasses on the studs, The exhaust studs get brittle and snap, The Exh gasses burn away the surface of the port, You can put stainless studs in. You need to take a close look at the condition of the exh port flange and hopefully it's not messed up from leaking exh gasses. Also look at the flange on the exhaust pipe as well. Often the ears are bent from people over tightening the nuts. Put a straight edge across between the bolt holes and if your flanges are bent you need to grind that surface flat again too and be careful not to over torque the nuts.

This surfacing tool is worth it's weight in gold but hard to find. The only other option is to remove the cylinder to have the surface repaired.


Jason


View attachment 5098
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[Anne]

This exact same thing just happened to me, on the same cylinder too. Pull the exhaust pipe off and check the flange for even-ness across the face. If you see daylight anywhere, use a file to get it even (or machine it if you have access to that, but a file will work). Clean off the face of the cylinder where it mates to the flange, and check that for even-ness too. Clean up the spark plug and the surrounding area, and check the cylinder to be sure it isn't cracked. Put it back together with new Blo-proof gaskets. Don't use the red sealing stuff - it's not rated for those temperatures, and it's not needed if you get the surfaces flat. Go fly it, then check for any grey deposit around the flange. Should be good to go once the mating issue is fixed.

Anne.

 

[Indabush]

I broke at the same place, and it was because I wasn't allowing it to warm up enough. That problem went away after I learned to let the CHT's come up prior to pouring the coals to it.

 

[Bill Ingerson]

Exhaust problems

Jason and Anne are right on target for exhaust repair. Jason did mine about a year ago and by using the milling surfacer it did a great job cleaning that cylinder exhaust port. Then the new studs and gasket and your good to go. Hope its a long term repair. Curious if they still make that milling machine ?




Bill

 

[mike mcs repair]

...
Then noticed the CO detector was really dark.

He suggests dropping the exhaust and thoroughly inspecting it, re-doing the gaskets,

Rene

yup pull it, its probably cracked/leaking/deforming somewhere else also....

a belt sander is the tool of choice for flattening the flanges on the pipes....

 

[SC3CM]

Thanks! Mechanic said the same thing about over torqued nuts.

Typically I'm pretty aware of warming the engine up before flying, but with no CHT gauge I wait for the oil temp to get to about 100.

Seems like everyone is saying the same thing so that's reassuring!


Rene

 

[Steve Pierce]

I talked to the manufacturer of the exhaust resurfacing tool and he no longer makes them.

 

[mike mcs repair]

I talked to the manufacturer of the exhaust resurfacing tool and he no longer makes them.

anyone got pictures/links to it.... I used one many years ago and wished I had one, and should make one now that I got the equipment.....

 

[Steve Pierce]

Mike, I have one I could loan you.

 

[tcraft128]

That is the same one we have. It works pretty darn good too.

 

[mike mcs repair]

Mike, I have one I could loan you.

View attachment 5118 View attachment 5119

thanks, the picture is enough to get me there....

the one thing I remember is it being to tall(grinder) and hitting engine mount on 185?? or something... will make it with a 90 angle grinder... that I have....

if someone can post a pic someday of the discs and mounts it uses I'd appreciate it...

 

[P.o.P]

My suggestion is to pressurize the system with a shop vac or leaf blower before disassembly.

Squirting soap & water will enable a much better evaluation of the condition.

Escaping exhaust gases from a leaking gasket will errode the cylinder itself in a relatively short time if not corrected.

As with most items; there are Limits on how much material can be removed from the cylinder.

Removing cylinders & sending to a Cylinder Shop could result in having them "Red Tagged".

Be patient & research with the folks here.

 

[Ruffair]

This is another timely topic for me,

as I was getting the brake pumped up on the right side, my friend Greg was looking over the cub and noticed the muffler was cracked 3/4 around where the pipe comes out on the right side.....

then he look at the stacks and finds one cracked 3/4 the way round on the left side.

I had a new muffler on the shelf, and got the crack fixed.
But, now needing to replace the stacks as they are all very old.

Lesson learned: I need to be in a little less of a hurry doing my preflight.

I'd like to put on a support like the PA 12 had. It supports the exhaust system to the gussett on the motor mount with a spring attatchment. Any one have one laying around or a photo..?
(This is going on a J3 with a C85)

Kem

 

[Steve Pierce]

O-235 has a bit more of a shake. PA12, PA16 and the PA22-108 all had those braces. How old were you exhaust parts? Dawley can rebuild what you have to new.

 

[Ruffair]

Don't know for sure Steve, The stacks are pretty thin. The broken one had been welded before.
I'm sure they are pretty old, just don't know how old.

 

[Fortysix12]

I like the old slotted screw driver test. Perfectly good looking muffler and then I find spots discolored/irregular surface and I can stick a screw driver right through.

Don't forget about the Sutton muffler conversion if too many parts are tired. Lots' of old stock 150 muffler systems for sale as well.

 

[skywagon8a]

Resurfaced exhaust ports. Be aware that when resurfacing an exhaust port there is a relationship between the other cylinders and the exhaust stacks. Once when I replaced an R-680 on a Cessna T-50, the old exhaust ring went on the replacement engine. During the first test flight the exhaust stack broke completely around at about an inch away from one of the cylinders. The problem was that the one cylinder had it's exhaust port resurfaced. The solution was to use two exhaust gaskets to eliminate the stress on the exhaust. Be careful of any stress that you may introduce into the exhaust system. It may look OK and it may not be.

 

[btracy]

Here is some more Photos of Pierces resurfacer in use

 

[Ruffair]

I like the old slotted screw driver test. Perfectly good looking muffler and then I find spots discolored/irregular surface and I can stick a screw driver right through.

Don't forget about the Sutton muffler conversion if too many parts are tired. Lots' of old stock 150 muffler systems for sale as well.

I don't think a Sutton would work for this, it's a J3 with a C85. But I like the way you are thinking..!

As far as sending it to Dawley for rebuild, as Steve mentioned, I think they would just use the existing stud "holes" and rebuild it around them.
Kem

 

[Steve Pierce]

That is what they do.

 

[Superchub]

Mike, I have one I could loan you.

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That is cool!! Where did you get that Steve?

 

[Steve Pierce]

You would appreciate this story Branden, fly market at OSH. Several people were in front of me commenting how it was over priced. Paid for itself the second time I used it.

 

[demoreel]

Anyone know of one of these for sale/rental? Got an L 0320

Anybody know where I can get one, or rent one?
Thanks,
Allen F.

Here is some more Photos of Pierces resurfacer in useView attachment 5133View attachment 5134View attachment 5135View attachment 5136View attachment 5137View attachment 5138View attachment 5139View attachment 5140

 

[larrym]

Anybody know where I can get one, or rent one?
Thanks,
Allen F.

May be too late to help, but available here. http://www.rulonaviation.com/aboutus.asp

 

[scruiser]

http://www.hangartoolbox.com/Search.aspx

Rank: 144 Aero-Grinder Exhaust Port Grinder PN:M92 The Aero-Grinder refinishes the exhaust port flange of the cylinder while the cylinder is installed on the engine. The tool works on Lycoming angle v... Rent: $78.00 Deposit: $270.00

 

[barijr]

Exhaust systems are one of the highest maintenance costs on any airplane. It never ends, fix one, break another. Almost every airplane I pull the cowl on, has a crack some where, or leak at the flange.