I have a small crack that I found in the exhaust stack, near the bend after it comes out of the cylinder. From the looks of it, It could easily be welded. I am wondering how welds hold up on exhaust stack, particularly in this high heat area... am I just buying time or would i be better off just replacing that piece of the stack in the long run?

Edit: exhaust has about 1100 hours on it.

My nickel is to replace the exhaust.

gunny

What kind of plane is it on.
I weld exhaust all the time. I just had a 185 collector repaired for half the price of a new one. Atlee dodge welded a whole new flanged end on it. Atlee dodge and a bunch of other shops can usually do repairs for allot less then new. Most of my repaired parts seem to last just as long as new parts before requiring repair. If it is only a crack i will just weld it myself, or you could take it to a welding shop and get a crack welded. You should be able to tell once you remove the exhaust if it is even work repairing. Thin heat damaged pipes without much "meat" remaining are probably better suited for the metal recycler, or old cessna 180/185 style exhaust with all the clamps on the collectors i just trash as well. Better to upgrade to something with slip joints.

Years ago, my dad was flying our Pacer when the exhaust broke in the same spot you describe, I believe on the copilot side, rear cylinder. He had it welded up and there haven't been any problems with it since then, probably 500+ hours.

That's good to hear. This is on a Lyc. O-320 in a PA-22. And yes it is on cyl #3.

Same setup, our 320-150 has been running real strong and just keeps going, but I REALLY hate working on the exhaust. I've had to pull it a few times to replace the rivets connecting the fresh air intake to the heater muff. After lots of fiddling and bloody knuckles to get the muffler out, I found a placard on the muffler itself that states to remove and inspect every 25 hours. Yeah right! It would be really nice to have a new exhaust system that is fully under the engine, not snaking around the back, between the engine mount and firewall.

My point is, your crack probably has a simple fix, but if you decide to look at new exhaust systems, I would move away from stock.

It is a pretty common problem.

I had the same issue. Unfortunately, I found it after getting gassed on a cross country...the heater baffles had cracked in a couple spots too, and then we discovered the less important crack.

It is easy to fix if it is done right. The first guy charged us 380 bucks for 4 small welds that had to be re-fixed just several hours later. A new unit was only 50 bucks more at the time. The second guy was a race car chassis welder and re-did it properly for less than 50 bucks and we then had it yellow tagged from a guy he worked with. No problems for the next couple hundred hours till a flange cracked.

I'd get it to someone who welds exhausts regularly. Atlee Dodge, Acorn, Aerospace Welding, etc. And, have someone pressure check the rest of your exhaust system at the same time if it hasn't been done recently. You do NOT want CO poisoning.

MTV

Thanks MTV. Yeah I get it tested every 50 hours per an AD, and have a CO meter as well. Not how I want to go. Going to run it by my mechanic soon so he can take a look.

coloradokevbot,
The exhaust system that you are wanting is the Sutton Exhaust System - directly under the engine - STCd for the Pacer - and it eliminates the AD.

The exhaust system that you are wanting is the Sutton Exhaust System - directly under the engine - STCd for the Pacer - and it eliminates the AD.

I agree wholeheartedly about the Sutton exhaust, but STC'd on a Pacer? I don't think so... Took me quite awhile to get a field approval to put one on my Pacer.

As far as welding exhaust, go for it, usually works great. Failures I have seen are when welds have been made on material which is too far gone. Exhaust tubing gets old and eventually transforms into some other material, almost like ceramic. We would see it a lot on #7 segments on the Beaver all the time.

Halestorm,
My mistake. You are right. The Sutton exhaust is STCd for the PA-12 and the PA18, not the Pacer. I did put one on my Pacer though, and I didn't have trouble getting it approved at the time. I thought it was g great conversion.

I was also gonna mention the Sutton exhaust. I know three guys who've had it field approved for their Pacers & it apparently wasn't all that big a deal.

Be advised that when some of these exhaust specialty outfits do a "repair", it's often a brand new part. But they call it a repair because they have a CRS license to do repairs, but not the PMA to manufacture new parts.

hotrod180 wrote:Be advised that when some of these exhaust specialty outfits do a "repair", it's often a brand new part. But they call it a repair because they have a CRS license to do repairs, but not the PMA to manufacture new parts.

Correct, and the beauty of that is that you effectively get a brand new part, but pay a LOT less than a new part from a manufacturer.

If it's a simple crack, it can be welded by an competent welder. As noted by others, though, if the metal is old, you may be better off to send it to one of the specialty welding outfits, and have them make it "like new".

MTV