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Stainless Steel exhausts


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My full stainless system (as described in the advert) is showing signs of age, any one know how long they last as mine is nearly rusted through in places :(

post-10430-1218028160_thumb.jpgpost-10430-1218028204_thumb.jpg

The last thing I need is for that to drop off :rolleyes:

spelling edit (dicklexea) :D

Sorry fella, but that is NOT stainless if its rotting like that....

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nope, just a stainless can and even that looks thin carp.... My friend makes stainless systems and offers them with a lifetime guarantee (as long as you have the car, as long as he lives or as long as you live) lol

That sounds a bit fishy :D

I'll get my coat ........

Mo

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Looks like another lie that was told in the advert, this landy is turning out to be the worst deal that I've ever had.

The thing is, it wouldn't be half the fun if everything went right ;) If we ever meet I'll show you my book of receipts, it's frightening, particularly to the wife :D

Mo

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There is stainless and stainless. You can get cheap rubbish stainless which rusts if you leave it out in the rain (£1 shop knife and fork set) right up to marine grade 316 stainless like my outboard motor tilt rams are made of, which won't rust even if permanently immersed in salt water, and various other grades in between.

Guess which end of the scale exhaust pipes are likely to be made of :rolleyes: but I'd guess a 316 grade exhaust pipe would probably need a second mortgage :o

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Not all stainless stays shiny, silencers are usually made of shiny-grade but I've got a stainless system in the garden ( :P ) that has surface rust all down it. I'd put money on the flanges being mild and the pipe being unshiny stainless, unless it's going really crispy.

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I'd put money on the flanges being mild and the pipe being unshiny stainless, unless it's going really crispy.

You're spot on Fridge. I bought a stainless system for my V8 90 some 14 years ago from Double S. Lifetime guarantee they said, well as long as I own the vehicle anyway! After about 10 years the flanges on the centre box, and the pipes each side of it, had crumbled away. How long do they think people keep Landrovers?

I called Double S to see if I could get some replacement flanges to weld onto the old pipes as they were fine. They offered to replace the parts concerned FOC, as long as I sent them the old pipes back to inspect first. What a pain to have to remove the whole system, I wanted to weld new parts on in-situ. Never mind the hassle of being left with no exhaust for a week!

As luck would have it a friend was passing through Devon a short while later and offered to pop in to them. He ended up speaking to the MD who was incredibly helpful and send him away with all the new flanges I needed.

His discussions while there revealed that they use mild steel flanges on their stainless pipes and silencers! What a surprise :o

BTW Landowner my system looked a fair bit worse than your pictures. How old is your system? Wonder if it was made by the same company...

Michael

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Same here.

Put a Double S system on my 90 in 1992.

A couple of years ago the flanges / clamps all rusted away.

They said the same to me - send the system back for inspection.

In the end I got them to post me some new flanges which I put on in situ.

Paul

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The thing is, it wouldn't be half the fun if everything went right ;) If we ever meet I'll show you my book of receipts, it's frightening, particularly to the wife :D

Mo

Not too worried about small faults but this landy has got the lot.

The gearbox has developed a noise in first, the transfer box is shot, both prop uj s were held together with rust and lubricated with dirty water, the front diff is fooked, there is a large hole in the floor under the drivers carpet, I could go on and on.

This is a land rover bought from an enthuisiast who assured me that it was all right as I didn't want to be doing any major repairs as I'm disabled, I can do most jobs but not major mechanicals.

So I bought it at top price and it's a dog and I'm broke

Rant over.

I will fix it eventually but I could have bought a much newer one in better condition for the money, great thing hindsight. :lol:

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The gearbox has developed a noise in first, the transfer box is shot, both prop uj s were held together with rust and lubricated with dirty water, the front diff is fooked, there is a large hole in the floor under the drivers carpet, I could go on and on.

That's only 7 things - you have a quality motor there :lol:

Most people tend to stay in double figures.

Les.

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Good quality stainless is 18/8 - 18% chrome 8% nickel non-magnetic material

Cheaper stainless is about 11/2 - 11% Cr 2% Ni but magnetic not as good as 18/8 but better than plain old mild steel

Mild steel has only traces of Cr and Ni left in there at the mill. Magnetic and rusts.

Stainless exhausts can be bad news depending on the exact type of material and the welding, it can be more brittle and fail easier than Mild Steel. :(

Get underneath your LR armed with a magnet and place on your exhaust system, if the magnet hits you in the eye it's good quality 18/8 stainless, however, if it stays put........................

Dave

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This is taken from an American welding forum I read.

Here is the link to the orginal thread; http://weldingweb.com/showthread.php?t=20984&page=2

Stainless steels go through some changes when heated up to temps between 800-1600°F. Being this is a part of turbocharger, I'm going to assume that it gets at least this hot. If you used a low carbon grade of tubing and filler, you should be alright. The changes I referred to are in part driven by the presence of carbon in the steel. No carbon = no changes.

The bad news, and the thing I don't like about using Stainless in exhaust systems upstream from the catalytic converter(where temps are very high), is that the exhaust gas stream is full of carbon(CO, CO2, and a soup of partially burned hydrocarbons). There's also a lot of water vapor. If the steel spends a prolonged period of time in the critical temperature range, the carbon in the exhaust gas will slowly move into the steel. This in turn will degrade it's corrosion resistance. Combine this with heat and water vapor and you'll see corrosion of the stainless.

Generally speaking this corrosion is widespread and progresses slowly from the inside out; so that most people are satisfied with the lifespan of the components. But weld them incorrectly, and you can see much more rapid failures. Everything you've done looks good to me, so I don't see you having any problems. I'm assuming from what you've said that you don't have any sugaring on the back sides of the welds. This would be the best indicator that you could have durability troubles with the weldments.

If you do see cracking, and you didn't go looking for low carbon tubing or filler, try switching to low carbon grades. I'm confident you'll have better luck with these.

There's a whole lot of other factors that influence how fast this corrosion can occur. Better grades of stainless hold out longer(300 series are good), but a lot of the OEM and mass produced aftermarket stainless exhaust components are 409SS; which is a poor man's grade of stainless. It's cheap, because it's got barely enough chromium in it to be called stainless steel.

The 304 you're using is much better than 409. But if you need more longevity you could look at using 316SS, or on of the better Ferritic grades like 436SS or 446SS. These grades are better for high temp corrosion, but will be much more expensive. I don't know if these are available in the right size tubing either...

The other factor that's important is that if you heat the stainless up above 1600°F, but don't melt it, you can actually reverse some of the degradation. This is dragging on, so I'll skip the explanation for why. What's important to know is that holding temps between 800-1600°F for extended periods of time, and introducing carbon, will hurt the material. How much damage and how long to failure is a function of time, temp, and carbon availability.

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You can get 316 stainless A frames for RIBs etc (used to mount nav lights on at the stern) which are usually 2 inch or 3 inch tube so I guess the tube is available in the right sort of sizes ... but an A frame with maybe six or eight feet of tube in is usually the wrong side of five hundred quid and that doesn't have any silencers in so I'd hate to think what a complete exhaust would run at :blink:

Interesting info on the corrosion :)

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I mate of mine builds exhaust systems for the minis he also builds, he uses 316L grade. The tube he uses is a common size for the dairy Industry so is not too expensive, you can by loads of different Dia and Degrees of Bend, I have some on order to build a system that exits just behind the NS door on my 90, thought the wheel arch panel.

Here is a link to a Co that supplies stock bends and lengths as well as custom requirements.

http://www.ojzengineering.co.uk/page.php?page=100

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It sounds like you guys need to meet

http://www.powerflow.uk.com/about.html

A few years back i had an exhaust off them top quality i must say.

Also a friend of mine replaced all his hoses in his engine bay including turbo pipes with stainless pipe instead of hoses, it did look smart.

If i rember corectly i would say expect a bill of £400.

I used the dealer in Nottingham Big City Tyres

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