Technical Marman V band exhaust connections Wow, leak free v bands

I came across these exhaust clamps that claim to be leak free and now I’m second guessing my choice to use the regular flat flange v band exhaust joints.

Anyone used these?

https://m.ebay.com/itm/MARMAN-FLANG...735754?hash=item3d3259914a:g:5yEAAOSw44BYD6LR

 

We used Marman clamps at Chrysler engineering for all our dyno hookups. They worked fine.

 

I have no experience with those you are asking about, but as far as V-bands go, these ones are great.

https://www.deedsengineering.com/shop/v-bands/v-band-clamp-kit/

They are not flat faced, the have a step on the face for easy alignment, and the also have a step inside that works as a tubing stop. Stick it on the tube till it stops and weld it on.

 

I don't think they are any better than the flat faced ones in fact he talks about them in the video. ( In the video he shows a used one with a lip like that, it was leaking )
I'm a believer, so much so that after experiencing the pain in the ass assembling my flat faced V band clamps and the fear of them leaking, I am going to order up 4, weld them in and have my exhaust system re coated with ceramic.

 

I’ve never had any trouble with regular v-bands clamps leaking, but I do like the way these fit together.

I’ve typically used the ones with no step but let the leading piece of pipe stick out of the flange about 1/8” and the opposite side has the pipe recessed the same. Helps with alignment and sealing.

 

Yes, when installed like this I've never had one leak. I started using them 20 years ago. I also use a Flex Bellow joint to stop torque Twist transfer into the Exhaust system. And this is what they look like. They come in all pipe sizes.
The Wizzard

 

The Sprint Car guys like them also because of the adjustability & for the quick replacement of the headers after a crash. That way there is no need to weld the headers & mufflers as a one piece unit. Yes, the state of CA does require race cars to be muffled.

 

So, I tested my flat faced V band exhaust connections even though I haven't run actual exhaust through them yet.
With the bands tightened as much as possible without breaking them, I shone a light into the pipes and turned the lights in the shop out.
Light shining out through the bands opening.

Then another test, tape the ends with a little duct tape and put a little air pressure in.
A small bit and it was obvious the flat faced v band connections are garbage.

They leaked a lot, not just a little.


So I ordered up 4 Marman joints and will put them in for a leak free exhaust system.
Then another trip to the ceramic coating shop.

 

Sorry to hear that Blue One. I have a question, When you installed the V-Band rings did you let some pipe overlap the joint? Meaning is there 1/4" of pipe past the flat face of one piece and on the adjoining ring equal amount behind the flat face of joining ring causing an overlap at the face of the rings? Also do the two rings meet flat and flush to each other?
The Wizzard

 

Those bellows would work great with fenderwell headers, I will have to keep them in mind.

 

I've the flat face V-band on my 46 Olds project for a clean simple look and to provide ground clearance with nothing below frame. I'll use a silicon film when it comes time for final assembly.

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I'm sure that we used the same type exhaust clamp on a number of WWII reciprocating aircraft engines when I worked for an aircraft salvage company at Cimarron Field outside Yukon, OK back in the early '60s. We had about 1500 Allison 1710 ci V-12 engines in crates that we rebuilt to power mud pumps in the oil field. We also had several different types of radials. My job was to take them to the test block, hook everything up and run the engines in for 4 hours. Even with earmuffs, they were extremely loud. If they were still running after that time, they got shipped to the oil patch. When they blew up, we got to build them again.

 

No, I didn’t do that as I was told they would seal up and not leak.
So much for that.

And yes I’ve had them apart several times trying to be sure they are lined up and flush- flat, tightening them up first and then the hangers next.

I only wish I had known about the Marman joints to begin with.
Before ceramic coating and all that.
Live and learn.

Better and easier to fix it now rather than later, nothing is more irritating than exhaust leaks and burning up the paint on surrounding parts.

Good luck with trying to use silicone or anything else to seal them.
Apparently not much will work to stop the leaks.

I’d just replace it with a Marman joint and be done with it.
They aren’t much bigger than any other v band clamp.

I’m sure you did as he mentioned in the video that these style of joints have been around for a very long time and are also used in things like irrigation systems.

 

Use the V band all the time on Cummins Diesel stuff , leak free and removable as needed


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If you are referring to the standard flat flange V bands they are not leak free.
They always leak to one degree or another.

 

Pist-N-Broke: Are those available in stainless and if so, what company?

- EM

 

Something to be aware with on those flexible braided bellows joints.
They are fitted on a great many vehicles as OEM equipment.
They will eventually break down and fail in the internal flexible ribbed bellows which is hidden under the stainless braid which stays intact.
There was a news story in my area just recently where the failure of one of those type of joints led to the carbon monoxide poisoning deaths of a young couple.
Apparently it's common and happens more often than you know.
If you look it up you may find news stories on it.

 

Yes they are. Go to S.P.D. Exhaust then to accessories and to Bellows. Or go to www.spdexhaust.com
This Co makes very high quality products however not many of them come with instructions and not all home builders are qualified to install them.
The Wizzard

 

We use the Marman style on our Volvo cabovers with the Volvo engine, they're pretty good, but the female side flange does occasionally break.

The Cummins style v-bands do leak sometimes and you can get them to seal again if you loosen the clamp and rotate it. It also helps to tap it with a hammer as you tighten it so it'll bite harder.

We have another style that's basically a joint, ball and socket style, pre-assembled and you can make any angle you want, it'll leak cold, but as soon as there is some heat it's a really good sealing joint.

 

Here's the story on the leaking flex joint deaths.
https://globalnews.ca/news/3940804/edmonton-mechanic-urges-drivers-to-check-for-exhaust-leaks/

 

I do not disagree that some are junk but I think it depends on the manufacturer. I have one on my OT Nissan truck and its 18 years old with 340,000 miles on it. The entire exhaust is original and except for a leak in another part of the system due to the bolts rusting away its been leak free. I have to deal with the mandated emissions check every two years also. I wish I could tell you what brand they used back then but I have no idea.

 

My 4 replacement Marman joints have been shipped to me.
I'm all set up with fire blankets to cover all the pretty and shiny bits
The saga can continue.

 

Agree with "Deathrowdave", my cummins is coming up on 13 yrs old and still no leaks. Mine have been apart
several times installing and removing exh brake and manifold replacement, gotta get em aligned right to have
no leaks, NO tolerance for misalignment.

 

I had a little time to watch the above posted Video. Wish I had time to post everything that went through my head as I was watching it. What I will say is that if I had a product to sell I would like to hire him to do my sales pitch. He's good. Full of himself and his product as any good salesman should be. It was entertaining to say the least.
The Wizzard

 

I think that the whole sales pitch thing becomes easier if you have a good product to offer and as far as the full of himself part goes, l didn’t get that impression at all.

It’s easy to present something if you have some experience and knowledge to back it up which having been in the business long enough I believe he has.

It’s almost similar to what I’ve been doing for the past 20 years, teaching.

It’s also easy to be cynical and have random thoughts of mistrust but where does that come from?

But no matter.

I started this thread to bring forward a product that I think will solve a problem I’ve encountered with my build possibly because the V bands I bought were cheap and poor quality to begin with and don't even come close to sealing up like they should.

And, maybe these joints might be interesting to someone else who would want a decent quality exhaust joining system for their project.

That’s the purpose of a technical thread I think.

On top of all that, these are a totally made in the USA product, that should count for something as well.

 

Are these the type you used that leaked?

These are from Dynaflex Products, I got them from a local commercial truck parts house. I used them successfully for years at my custom header/chassis shop, usually on cars that were very low. They slide over the tube. I usually slid the upstream side on until at least 1/2 - 5/8" projected from the flange end, that way it was like one continuous tube with the tube joint offset from the flanged joint. They never leaked for me.
I do like the design of the Marman version you posted, clever.

 

That would be the way to use them for sure, used the way you described they would probably be better than what I used.
I was told to just let the flat machined faces of the flanges do the sealing that they would seal fine, which they do not.

What I used looks like this.


The Marman joints will be a big improvement.

 

Oh yeah, face to face with no gasket is definitely not going to seal well. Pretty nice parts though, too bad.

 

What's the largest size available? Building an OT engine, and like the design.

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https://gbemandrel.com/
Ask them.