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Urgent Heater Muff/Exhaust Heads Up!

I've had 2 Robbins heat muffs on my -6 since day one (2000). I had trouble getting them to clamp the pipe tightly until I oversized the tie rod holes slightly. That allows the end cap halves to move past each other a little more and clamp the pipe. 1800 hours and no wear on the pipe.
 
Add me to the list. I found this damage to the aft shroud during my 50 hour oil change. The force was enough to snap one of the steel rods! Planning to order Robbins end caps tomorrow.
 

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Thanks Bill for starting this great thread! I'm just about to install my exhaust system and didn't know about the head muff issue. Just ordered replacement end plates from Rick.
 
I had some exhaust material rubbed off as well, just swapped them for Rick's aftermarket part, those clamps are not going anywhere, far superior, 10/10!
 
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I appreciated the heads up on this.

Checked mine last week and all seems well. I will add this to my inspection routine however. 380+ hours.
 
Is anyone aware of this being an issue with Vetterman supplied heat mufffs that have been supplied in the last six months?
 
My Robin Wings carb heat muff has been going strong since 1997. The end caps are loose after 3,400 hours so I phoned Rick to buy new ones. He no longer has the website but does support over the phone for RV aircraft. If you need carb heat or cabin heat muff, I highly recommend Robin's Wings. I have not seen a better made product. I have seen some cost more money and some cost less money but never any that were better quality.
 
I discovered a problem with one of the heat muffs on my -14A today. Actually, the heat muff was only part of the problem, which also involved the exhaust system. As a data point, the airplane has 700 hours on it.

I thought that both muffs fit tightly enough on the exhaust pipe when I installed them. They are held in place by bendable tabs. Today I noticed that the tabs on the inside diameter of one of the end plates on a muff had worn off. The resulting sharp edge had cut a groove into the exhaust pipe around a portion of its circumference.

I did not measure the depth of the cut but it is very definitely noticeable. I just ordered replacement end plates for both muffs and will pull the assembly apart tomorrow to have a better look at it. There may be damage to the exhaust pipe under the other three end plates but I only noticed this one in the limited time I had.

This is an area you may want to pay attention to as it is not very noticeable and could create some exhaust pipe damage before you see it. And clearly, an exhaust pipe leak into a heater muff is not a good situation.

I don't now how tightly the end plates are supposed to grasp the exhaust pipe, but certainly I intend to bend the tabs sufficiently to tighten up that joint when I install the new parts. It would be be an improvement if the end plates were designed such that they could be attached rigidly to the exhaust pipe with a hose clamp instead of via a friction fit based on how you bend the tabs.

Mine failed as well, I decided to remove them.
 
3 more RV-14's found with significant material worn from the exhaust pipe with the stock clamps ... basically, every 14 I've seen with the cowl off ... this is going to be a very common issue ...

I urge everyone to check theirs and get the revised or aftermarket replacements asap!

(probably needs to be an SB)
 
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I figured I'd pile on here.

I've been watching mine now for the past 200 hours and could tell the stock setup was not going to last so I proactively purchased the Robbins ends. Over the past few months I've noticed the stock muffs slightly loose which I had attributed to "breaking in" or maybe I hadn't bent the tabs far enough inward.

I had the cowling off today for an oil change and noticed they were a little looser than had been so decided to go ahead and swap them out. The stock ends on one muff were completely broken in the area around the rod/nut. After the easy swap to the Robbins, I can already tell they are much more robust and will last!

If anyone does have interest in ordering the Robbins muffs, you have to email him as there is no website. Unfortunately I can't find the email address, but I'm sure someone on here has it.
 
We have noted a lack of longevity of the heat muff end ribs and it is currently being looked at by engineering.
More info when I have it.

In the mean time, be sure to do a thorough exhaust system inspection during each condition inspection in accordance with AC43.13 Appendix D.

Scott,
Was there an outcome from the investigation with engineering?

Thanks.
 
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I checked mine when I first heard of the problem earlier this year but found no wear.

At the last annual however, two months ago, I found that the circular ends of the forward muff had cracked and needed to be replaced. I ordered new parts, including enough to do the rear muff.

The parts were backordered at the time, but they shipped about a month ago. When I rebuilt the muffs, I found no wear on the exhaust. It is on my list of items to check whenever the lower cowl is off.

450 hours on the old ones with no wear. We'll see how the new ones hold up.
 
I am installing the sleeves and I made a slider in one of the holes so that when I tightened them with the clamp it fits more
 
Joined the club

87 hrs TTSN Thunderbolt IO-390. Found doing annual. Aft muff assembly end broken Replaced end caps with Robbins product (great quality). Rest of the annual was good!
 

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Just make Rick Robbins the supplier to Vans for the end plates.

This is the correct answer. The Vans muffs are mis-engineered and should not be installed. Mine failed under 100 hours. I believe he used to be the supplier before they were brought in house.
 
First off, A very happy retirement to Scott, aka rvbuilder2002.
The reply from Vans support is that engineering is working on an upgraded part. Nothing as yet though. I ordered my replacement end caps from Rick Robbins today, shipped today. Has them on the shelf.
 
Any update?

This thread has been quiet for about a year - any update on better end plates for the cabin heat exchanger? Mine are still ok, but would prefer to have spares just in case.
 
This thread has been quiet for about a year - any update on better end plates for the cabin heat exchanger? Mine are still ok, but would prefer to have spares just in case.

I do not know with absolute certainty, but with all of the different things that have been going on in the past year I think engineering made the decision to just purchase parts from Rick and include them in the kit, but you will need to check with someone at Vans to confirm that is correct.
 
This thread has been quiet for about a year - any update on better end plates for the cabin heat exchanger? Mine are still ok, but would prefer to have spares just in case.

The TURBO heat muffs sold by spruce are made in Las Vegas by a guy named Dave. They are robust and fit great with outstanding customer service. Internally they have aluminum rods wrapped in a copper spiral. They really produce a lot of heat. They come with airflow reducers that you can swap out to slow the speed of the airflow though them.
 
The TURBO heat muffs sold by spruce are made in Las Vegas by a guy named Dave. They are robust and fit great with outstanding customer service. Internally they have aluminum rods wrapped in a copper spiral. They really produce a lot of heat. They come with airflow reducers that you can swap out to slow the speed of the airflow though them.

That does look nice. My heat muff is working ok, but I had read in this thread that the ends often fail, or get loose. Seems that you can buy new ends, but they are only for RV-14 builders. I've also read that Van's is considering a new end that's more robust, and will hold the heat muff tighter.

https://store.vansaircraft.com/ex-00013k-l-set.html

While I might need to just buy a new one for $200, I'd rather buy just the ends and use the rest of that money for 2 hours of gasoline. :D
 
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