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Author Topic: Exhaust joints  (Read 846 times)

Jordan

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Exhaust joints
« on: January 28, 2019, 02:00:22 AM »
The exhaust system is made up of sections of pipe and a muffler.
They are slip fit to each other, with ends expanded where necessary so one pipe end fits into the other.
I find that there is unacceptable leakage at all joints when the engine is running.
I'd love to have a totally sealed system, without having to weld the various pipes/muffler to each other.
Could there be some solution?

BruceM

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Re: Exhaust joints
« Reply #1 on: January 28, 2019, 03:29:06 AM »
I had the same issue.  I used the highest temperature silicone I could find at the time- the copper doped high temp stuff, Permatex I think.  Took it apart and gooped the joints. That did the job.

ajaffa1

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Re: Exhaust joints
« Reply #2 on: January 28, 2019, 07:04:08 AM »
Hi Jordan, I have tried a few different methods depending on the size of the gap. Larger gaps I fill with fire cement, smaller gaps with high temp silicon. I have also had some success with exhaust repair bandages available from your local auto center. When using fire cement, please wear rubber gloves as it is very nasty stuff and will dissolve the skin on your hands. You need to let it dry out before firing it by running your engine.

Bob

Jordan

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Re: Exhaust joints
« Reply #3 on: January 28, 2019, 07:44:47 AM »
Speaking of silicone, I wonder if the hoses that are made of this stuff and sold as "go fast" accessories for aftermarket turbocharged cars possibly suitable?
They'd need to cope with the change in size of a few millimeters as the jointed pipes' diameters vary.
I sent an enquiry to a supplier about this.

ajaffa1

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Re: Exhaust joints
« Reply #4 on: January 28, 2019, 08:15:13 AM »
Hi Jordan, I`ll be very interested to hear what they come back with.

Bob

dax021

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Re: Exhaust joints
« Reply #5 on: January 28, 2019, 09:10:45 AM »
I had the same issue.  I used the highest temperature silicone I could find at the time- the copper doped high temp stuff, Permatex I think.  Took it apart and gooped the joints. That did the job.

That's what I did.  The Cu silicone gasket sealer works perfectly and have had no leaks for more than 2 yrs.  You could also put an exhaust clamp around the joint and fasten tightly.  Unless your pipe is 3mm (1/8") wall thickness, this will crimp it on.

Jordan

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Re: Exhaust joints
« Reply #6 on: January 30, 2019, 09:43:10 AM »
It's been a couple of days, and no word from the silicone hose suppliers.
Must have been too technical a question for a sales person.
I'll go with the Permatex Cu-silicone stuff in a tube.
Thanks folks.

glort

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Re: Exhaust joints
« Reply #7 on: January 30, 2019, 09:58:52 AM »

Back when I had hair and a 10" smaller waistline, I used to muck around with model boats.
Of course me being me, while everyone else was running 3.5CC engines, Mine had a 50CC motor. Wasn't real fast as I could never get a big or aggressive enough prop for it but the thing sure had some grunt when towing a rescue float setup and dragging dead ones back in.

We all used Silicone tube for joining the exhaust and it held up fine on my Petrol engine before the water cooling dump.
That silicone was a white/ opaque colour ( if it indicates type at all) and quite thin and pliable.

I don't think the exhaust on listers would be too hot unless they were really overworked so I can't see why the silicone go fast tubing would be a problem... if it is real silicone and not 10% silicone and 90% some cheap rubber base.

vegoil

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Re: Exhaust joints
« Reply #8 on: January 30, 2019, 01:13:08 PM »
Just to give an indication of temperature My CS 8/1 Runs about 220*C 6" from the manifold and 130*C 4 foot from the manifold. I bought a tube of exhaust sealant from a exhaust and tyre garage works good (no leaks). give them the size difference of the pipes and they will keep you rite.

Cheers

John
« Last Edit: January 30, 2019, 04:56:08 PM by vegoil »

38ac

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Re: Exhaust joints
« Reply #9 on: January 30, 2019, 02:56:22 PM »
There are aslo stainless steel band clamps that surround the joint and seal tighly. Used on large trucks so a truck parts place is where you look for them. A bit spendy but solid reliable fix.
Collector and horder of about anything diesel

Jordan

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Re: Exhaust joints
« Reply #10 on: January 30, 2019, 10:54:05 PM »
I got a piece of silicone hose from a friend.
It has some textile insertion material in it.
I found it very resistant to both stretching and to being compressed down to a smaller ID.
So that's ruled out for my exhaust system, where it would need to cope with differing diameters at the joint.
Unless I can find some with the needed sizes built in, but I'm wasting too much time already...
« Last Edit: January 31, 2019, 12:58:53 AM by Jordan »

glort

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Re: Exhaust joints
« Reply #11 on: January 31, 2019, 01:53:09 AM »

Most car part shops sell silicone reducers, pipe stepped from one size to another.
if your pipe is standard sizes you should be able to get what you need.

Jordan

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Re: Exhaust joints
« Reply #12 on: February 08, 2019, 11:20:24 PM »
I assembled the slip joints with some Permatex copper/silicone that BruceM and others suggested.
Cleaned the surfaces with Acetone, put a bead on the inner surface, 2 beads an inch apart on the outer surface - boy, it's thick stuff, needed some squeezing out of the tube even with a 5mm hole in the nozzle. Then the joints were slipped together.
Left it overnight, started engine.
It's nice to breathe fresh air in the shed.

Johndoh

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Re: Exhaust joints
« Reply #13 on: February 09, 2019, 04:14:17 PM »
My missus has silicone baking trays for flans and such like so it can take a fair bit of heat
It is better to light a candle than to curse the darkness

veggie

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Re: Exhaust joints
« Reply #14 on: March 01, 2019, 03:02:09 PM »

I used  the stretchy Silicone exhaust tape on my Listeroid exhaust joints and it works great to close off any tiny leaks.
The problem is at the first joint in my system is only 1 ft. from the cylinder head.
That joint reaches 500f under heavy load and it cooks the silicone.
Turns it from Red to Brown and starts to curl and peal off.

So be aware that the silicone tape has limits. Otherwise it's great stuff.

veggie
- 6/1 GM90 Listeroid - Delco 33si Alternator
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