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MG MGA - New SS exhaust giving me fits!

Purchased the Tourist Trophy stainless exhaust from Moss.....I have used this same exhaust on two other MG's, without a problem...Always loved it....
Anyway, I also purchased the ss exhaust clamps (correct size)....
Where the middle pipe connects on both ends, I cannot stop the exhaust from leaking....
The connections are all the way into the front and rear (muffler end) pipes....
My first question, is : Should the clamps be over the splits in the pipe, or should they be on the unsplit portion of the pipe?
Second: How tight should I make the clamps?...If they are just firm, there are more leaks...Torqueing down, the leaks seem to slow, but still not stop.
I thought about using muffler cement inside the connections, but don't know how effective this stuff is on stainless.
Thanks for any help.
Edward Wesson 60MGA

Edward. I fitted the Moss T T stainless exhaust a couple of years back & have had no problems.

What type of exhaust clamps are you using? Looking at my invoices I used Mikalor heavy duty stainless steel hose clamps, also would have used some exhaust assembly paste. Because these hose clamps are not the U bolt type Iím pretty sure that I positioned them over the splits, but I would need to check this.

R A Evans

Are the clamps really the issue? Or is it a case of pipe diameter variation with 2 systems from different manufacturers?

Steve Gyles

It's the same Moss TT system that I have used twice before....The clamps are the ones suppied by Moss, at $4.75 each, and made specifically for stainless exhaust systems...I have no way of knowing if the pipes are made by more than one MFG. company, but they were a pretty snug fit on both ends. These are pretty high quality units, and I would really be surprised if the problem is with pipe diameter.

How is the clamp bolt oriented on your clamps?...These are single bolt clamps, more like a hose clamp, with a plain band, and a sliding bolt cover.

Does anyone know how much torque there should be on the clamps....Should I be using "crushing" force? Will the clamps fail with too much torque?

Edward Wesson 60MGA

Ed, take the pipes to a muffler shop, they will have an expander roll to enlarge the inner pipes foe a closer fit.
Art Pearse

I agree with Edward, these TT exhausts are very high quality units; the fit between the inner & outer is very snug, in fact I do remember having to open up the outer split pipe slightly to allow it to slide in.

Edward, the clamp supplied to you by moss sounds like it is similar to what I fitted (single bolt, band type) also made in Spain (Mikalor). Visit their website, they have max torque values. For 47-51mm hose clamps the max torque is 16Nm.

Suggest that you dissemble everything, clean up & re assemble with exhaust paste. Also it may be worth checking the whole exhaust system is not under any stress that may have been caused by uneven tightening of the support brackets.

R A Evans

I'm with Art on this. A long time ago I had a Stainless exhaust from Moss and one pipe was much smaller in its outer diameter compared to the inner diameter of the pipe it was supposed to slip into. I contacted Moss & the manufacturer who offered to take it back and investigate etc, but that was too protracted. I went to an exhaust shop and they expanded the smaller ID pipe. Worked fine.

C Manley

Thanks again for all the suggestions....
We live in a very rural area, where there are no muffler shops locally....It would be a real "process" to take the car to a shop somewhere....
But, I have to say, that I could barely get the pipes to fit into each other...I seriously doubt that they could be put back together after expanding.
I'm going to check the torque on the clamps....
If that is o.k., then I'm taking the two pipes loose, and sliding them apart, and adding muffler sealer....
I may install a second clamp on each end.
Edward Wesson 60MGA

Edward, I have checked the position of my band type clamp on the exhaust pipe. I was correct in that the clamp sits over the slots Ö.. see attached picture.

If you decide on separating your pipes then because you have used the band type clamps it should not give you any trouble. I remember many years back I had a lot of grief when trying to separate a muffler that had been attached with the conventional U type.


R A Evans

Thanks for the photo....
I reattached everything , and used muffler cement in the joints, before clamping them (with the band clamps)....I'm waiting until tomorrow to see if the cement works...
If I ever have to take the pipes off, I can do it in one unit (which is the way I took the old one off).
I did buy standard "U" clamps, but have not used them, yet...
I looked at the old pipe, and the "U" clamp at the muffler, was put behind the slots, and you can see that the whole circumferance of the tube was collaped with the pressure, so maybe using that type clamp , there is a different location.
I will post my results tomorrow.
Edward Wesson 60MGA

Well, I used muffler cement in the joints, and re-tightened the clamps....Started the car today (after allowing cement to harden), and I don't see any more leaks. I bought standard "U" clamps, and will use them behind the band clamps, if they begin leaking.
I left a message at Moss, to call me, and they did (after waiting a day and a half), and tell me what I should do....
Basic answer was use muffler cement, and torque the crap out of the clamps...
Also said that if they leak a little, it's not a big deal...Wow, I didn't expect that from the technical dept at Moss...!
Edward Wesson 60MGA

Here's a photo of the finished , and now working exhaust....I may be imagining it , but without the extreme bend in the previous , hoked up, system, I think the car is accelerating much better....Wonder if it has a little more power with the cleaner exhaust?

Edward Wesson 60MGA

What advantage does the TT exhaust have compared with a standard stainless system.

You have indicated it may have less back pressure, does it sound any better than a standard system and does it use the normal manifold?

J Bray

A friend of mine fitted a ss exhaust and thought that the sound was 'tinnier' than his earlier mild steel exhaust. I cannot think why this should be and it may have been a very subjective response by him. Mine has always been ss so I'm not in a position to judge.
J H Cole

Personally , I think it sounds great!...It is more mellow and less intrusive than my Monza-style exhaust.
The PO had obviously had a real hack job on the old exhaust pipe, and there was an extreme bend in the pipe that reduced the diameter , more than 34%!...
I didn't realize how big the bend was, until I had the old exhaust off the car, and measured the difference in diameter....It went from 1 3/4" down to 1 1/8". This was an attempt by the exhaust mechanic to prevent heat from reaching the bottom of the floor...They , evidently, never heard of a heat shield!
Power difference is amazing....
I used this same system on my TD, and B, and , though the difference wasn't this dramatic, it was a definite improvement in performance.
I have no way of knowing how this compares with some other SS exhaust systems, since I have had no experience with them.
Edward Wesson 60MGA

A friend of mine had a 73 MGB. He installed a SS exhaust system (this was twenty years ago). When we went for a ride, I thought the resonance from the exhaust system was annoying, in that you couldn't get it out of your ear, much like a mesguito buzzing around your head. It was tinnier, more like a brrrring, than a brrrreeer.
Take a hammer and rap a piece of SS metal, then do the same on the conventional exhaust system. Notice the difference?
Ray Ammeter

Maybe a 20 year old exhaust system sounds different than a new one...But I like the sound of this one....Probably a different manufacturer and design , as well. (Not sure that TT was even in business 20 years ago).
Frankly I thought the Monza exhaust note was annoying, especially during acceleration.

Edward Wesson 60MGA

This thread was discussed between 15/09/2013 and 22/09/2013

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